'— w—I—‘rv

 

«ti-twin ’s‘" -

.‘vvmu

?
‘ '3

c “ ’
.‘ngv-I

'S‘

v

i
.
.
x
‘:
,
it
x

41%.

 

my
1

 

,;-A M. ..- _

 

3212::- .'

     

.
E

i

s

x‘, s
19‘ .;
7: E
R

!

 

$4
7

fl?
. 1'5 at

)\

-.,. k¢~

W...
:‘mm

fi'fik'?‘

 

. 75:1:

.73»

“v-

3 2-21

.‘ iii}:
11,“ ;;,
.

 

Q!

33:34:21;

'2va M
. ‘1

   

L

..

..... ¢¢u¢
“'. ,.
.1

.“,4pru

.«u
.«wv-

.u.~w

. a.-

M4»
9.4
§ _.

in

“* taut:
w...
:3
”I
.54
.. ._ _
'22:? .1.
1M '
4.. ‘
m

.4

 

. A~ru-—~ ”Cr.

”nu-i»
-.a
.31.

‘ u“;
Shui
.‘J'v-‘J

.— a.

L-‘Em

   

' u.’
“£335“

a...

{.13.

.ot-
m >.--o-~

:w

, ...
29"." 1-0
..-..
Av-
..

‘

.a-«
o.-

0..

"3ch

flfil’
v: -
.n

c

n
F

3 "9m,
‘zfifigm
2’ 2353
,f, A

 

733:7”:
“fr“

 

{-1.

t
V

‘ §1
. - g»:
idii'iamafi

.u...

4-

i

M.
< x:
“a...
.4}
’

 

. 1 i I has . 3‘ h‘ If , '5‘
'V ’ ‘ - ' . k we ,
v‘iig. :ii‘ :93; . g} '35 *ézfixYVR-ig‘gg “3!.
as w: m
a 1 W5 ‘) “:1?)
31 3 “.53; »
1: ‘~ 3:;

“(J

CH UNIVERSITY LIBRARIE

llillllilll‘llilmuman

3 1293 01405 3304

 

 

 

 

 

 

 

 

 

 

 

ll

This is to certify that the

thesis entitled

FORENSIC SCIENCE IN THE HIGH SCHOOL CLASSROOM

presented by

Karen H. Pawloski

has been accepted towards fulfillment
of the requirements for

M. S - degree in BialaginaLScience

 

\

G

V
I / Major profeJH

Date_M_§LCll__2.L_19.9_6__

0-7639 MS U is an Affirmative Action/Equal Opportunity Institution

 

LIBRARY

Mlchigan State
Unlverslty

 

 

 

PLACE IN RETURN BOX to roman thb chockout from your record.
TO AVOID FINES Mum on or before data duo.

DATE DUE DATE DUE DATE DUE

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

:1
fifll—j

 

MSU II An Afflnmtlvo Actlon/Ecpd Opportunuy Institute»:

 

 

FORENSIC SCIENCE IN THE HIGH SCHOOL CLASSROOM
By

Karen H. Pawloski

THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

MASTER OF SCIENCE
Department of Science Education

1996

ABSTRACT
FORENSIC SCIENCE IN THE HIGH SCHOOL CLASSROOM
By

Karen H. Pawloski

The high school science curriculum is in need of science courses which
promote application of scientific concepts. In this thesis 1 have set about to design
such a course based on forensic science and at the same time promote responsibility
and higher level thinking among students. Included within the framework of the
course is an emphasis on improving technical skills, the ability to work in groups
and problem solving skills. I have integrated "real life" problems into the content.

Assessment is through written work and oral presentations.

Dedicated to Dave, Sara and Jeffrey

iii

ACKNOWLEDGEMENTS

The decision to develop this course, based on forensic science, was an easy
one. Implementation was much more difficult Several people kept me going,
however, and without them I am not sure whether I would ever have finished.

The first is the staff and administration of my school district. They trusted
me to develop this class without reservation. They gave me the funding necessary
and encouraged me to continue. Second, Dr. Merle Heidemann always had a word
of encouragement even when I was ready to quit. Dr. Jay Siegel, also, gently
pushed and prodded me to continue. The "all points bulletin" on the intemet was
an eye opener for me. Dr. Marty Hetherington willingly helped me whenever I
needed it including giving up lunch hours to meet with my students. Finally, I
would like to thank my husband and my children. They have done everything
within their power to encourage me to initiate and complete the document.

THANKS TO ALL OF YOU.

iv

TABLE OF CONTENTS

LIST OF TABLES .................................................................................................... vii
LIST OF FIGURES ................................................................................................... viii
INTRODUCTION - PEDAGOGY .............................................................................. 1
INTRODUCTION - SCIENCE BACKGROUND ..................................................... 6
IMPLEMENTATION ................................................................................................ l 7
EVALUATION .......................................................................................................... 44
DISCUSSIONS AND CONCLUSIONS - COURSE CONTENT - ........................ 52
HISTORICAL PERSPECTIVE
DISCUSSIONS AND CONCLUSIONS - COURSE CONTENT - ....................... 56
THE BEST AND THE WORST
DISCUSSIONS ANDCONCLUSIONS - COURSE CONTENT - ........................ 58
THE STUDENTS
APPENDIX A - BACKGROUND LECTURE INFORMATION ........................... 60
Section I: The Crime Scene ........................................................................... 60
Section II: The Microscope ............................................................................ 64
Section III: Chromatography ......................................................................... 65
Section IV: Spectrophotometry ..................................................................... 67
Section V: Electrophoresis ............................................................................. 68
Section VI: Hair and Fiber Evidence ............................................................. 69
Section VII: Documents and Handwriting Analysis ..................................... 73
Section VIII: Fingerprints .............................................................................. 74
Section 1X: Drugs ........................................................................................... 79

V

Section X: Toxicology ................................................................................... 81

Section XI: Blood ............... ‘ ............................................................................ 82
Section XII: Deoxyribonucleic Acid - DNA ................................................. 83
APPENDIX B - LABORATORY ACTIVITIES ...................................................... 85
Section 1: Paper Chromatography ................................................................. 85
Section 1]: Practice in the Use of the Microscope ......................................... 91
Section III: Examination of Hair By Light Microscopy ............................... 98
Section IV: Analysis of Fibers ..................................................................... 102
Section V: Carpet Sample Lab .................................................................... 107
Section VI: Determination of Lipstick Dyes Using TLC ........................... 108
Section VII: The Analysis of Questioned Documents. ............................... 112
Section VIII: Analyis of Inks By Thin Layer Chromatography ................. 114
Section IX: Visualization and Examination of Fingerprints ....................... 118
Section X: Shoeprints .................................................................................. 122
Section XI: Urine Analysis Using Paper Chromatography ........................ 124
Section XII: Ouchterlony Diffusion ............................................................ 128
Section XIII: Determination of the Peak Absorbance of a ........................ I32

Substance Using Visible Spectrophotometry

Section XIV: Identification of Salicylates in Blood by Spectroscopy ....... 135

Section XV: The Alcohol Breathalyzer Test: A Laboratory ...................... 141
Simulation

Section XVI: Agarose Gel Electrophoresis ................................................. 146

Section XVII: DNA Electrophoresis ........................................................... 151

BIBLIOGRAPHY .................................................................................................... 156

vi

LIST OF TABLES

Table 1 - Percent change of a variety Of tOpics ......................................................... 47
Table 2 - Before and afier comparison ...................................................................... 48
Table 3 - Percent change ............................................................................................ 49

vii

LIST OF FIGURES

Figure l - Scale patterns ............................................................................................. 70
Figure 2 - Medullas ..................................................................................................... 70
Figure 3 - Cross sections ............................................................................................ 71
Figure 4 - Root patterns .............................................................................................. 71
Figure 5 - Fingerprint Types ...................................................................................... 76

viii

INTRODUCTION
PEDAGOGY

In 1932 a baby was kidnapped from a home in Hopewell, New Jersey. The child
was that of Charles and Anne Lindbergh. Two months later the body of the child was
found half buried in the woods. The public was shocked and the parents were devastated.
Key evidence found at the home included a makeshift ladder which had been made of a
variety of woods. Following two years of investigation and analysis a suspect was arrested
and later convicted. The key investigator was a wood technologist. His most usefiil
investigative tool was a microscope (Saferstein 169). This is science at its best.

The world is intrigued and fascinated by crimes and their investigations. From the
Lindbergh case of 1932, John F. Kennedy's assassination in 1962, the Manson murders in
1969 to the Nicole Simpson and Ronald Goldman murders of 1994 the public has followed
high profile cases with utmost interest. The average person has been exposed to science
simply by listening to radio, watching television or reading the papers.

Discussions of bullet trajectories, blood types, stab wounds, writing samples and DNA
have filled lunch rooms, coffee shops and workplaces. Human interest in science has been
piqued by crimes and their solutions (or lack of ). It is because of this interest that I have
chosen to develop and evaluate a course on scientific application for my students (high
school seniors) with its basis in forensic science.

WWW published "A Nation At
Risk" in April 1983. This commission had been established by then Secretary of

Education, T.H. Bell in August, 1981 (United States: The National Commission on
Excellence in Education I). This resulted from "the widespread public perception that
something is seriously amiss in our education system." (United States: The National
Commission on Excellence in Education I). The goal of the commission was to assess
both college and high school teaching and learning and to compare American schools with
schools in other countries. The document began with, "Our Nation is at risk." and within

the first paragraph,

We report to the American people that while we can take justifiable pride in what
our schools and colleges have historically accomplished and contributed to the United
States and the well being of its people, the educational foundations of our society are being
eroded by a rising tide of mediocrity that threatens our very future as a Nation and a
people. (United States: The National Commission on Excellence in Education 5).

In addition, a list of "Indicators of The Risk" was derived. These included inadequate
performance on academic testing by American students when compared with other
industrialized nations, 13% illiteracy of 17 year olds in the United States, declining SAT

scores and...

Many 17-year-olds do not possess the "higher order" intellectual skills we should
expect of them. Nearly 40 percent cannot draw inferences from written material;
only one-fifth can write a persuasive essay; and only one-third can solve a
mathematics problem requiring several steps. (United States: The National
Commission on Excellence in Education 9).

As expected, the Nation was in an uproar and changes in education began.
Promoting students beyond the knowledge and recall level of Bloom's Taxonomy
became a priority. The overall goal of the educators, politicians and parents was to

promote higher order thinking skills in all levels of education.

The ability to read and understand content area materials is one of the areas which
needed and still needs to be improved. Currently, high school students in Michigan score
poorly in this area on current assessment tests. It is the opinion of many experts that
improving reading for understanding will promote reasoning skills, higher order thinking

and problem solving.

Using what they have read or heard as a catalyst for thinking about ideas, issues,
and problems suggested in their reading requires that students engage in many

skills listed in thinking taxonomies. They will need to evaluate evidence, draw
conclusions, make inferences, develop a line of thought, etc. Students need to
engage in such situations frequently, if we are going to help them develop the
reasoning capabilities" (Beck 678).

Suggestions for improving reading and reasoning abilities include promoting background
knowledge to the reader and focusing on problem solving (Beck 667-679). This needs to
occur throughout the curriculum.

Improvement in the ability to write also has been established as extremely
important. Journal writing has been shown to be a usefirl tool in promoting thoughtful
writing and reflection and therefore promoting higher order thinking skills. Journal topics
which begin with, "What if ...?", "This concept reminds me of ...?", or "In lab, I tried to
figure out?..." can be used to stimulate thinking (Lozauskas and Barell 44). As stated in
the article, Reflecfmc Reading, by Dorothy Lozauskas and John Barell

Although it does take some time to read the journals, we gain insight into our
students' general thought processes, their understanding or misconceptions
about significant concepts and scientific processes, and even questions they
were too embarrassed to bring up in class. The result is an enhancement

of the teaching and learning processes (Lozauskas and Barell 44).

Besides promoting thinking, journal writing teaches the student to convey information in
writing. -

In addition to reading and writing as vehicles to promote higher order thinking
skills, other strategies have been proposed. A very important tool is the ability to think and
work as a team. Cooperative learning is a strategy which has been developed as a response
to this.

Promoters of cooperative learning base the process on the idea that advanced
learners can help less advanced learners and vice versa. By working in groups the students
each have the ability to participate and, given proper structure, will participate. By
formulating individual ideas and debating them as a team a higher level of problem solving
can occur. This promotes higher order thinking for all of the students and encourages team
work.

In science higher order thinking requires manipulation of variables and reasoning
based on these manipulations. Yager and Penick ( l 987) suggested there is strong evidence
that many science teachers continue to present science primarily by lecture and question
and answer techniques (Y ager and Penick 51). There is a definite need in science
education to bring about a change in this by making a move towards more "hands on"
manipulations in the classroom.

My goal when designing this unit was to take all of the above needs and
suggestions and incorporate them into a science cuniculum, specifically a semester long
course. In addition I wanted to base the course on a topic which would promote learning
science in an enjoyable, applicable and yet challenging manner. For these reasons I chose

forensic science as the topic for this course.

Topics within the Forensic Science framework incorporate Biology, Chemistry and
Physics. Therefore I chose to design this course for students who had completed most, if
not all, of the above classes. The majority of students who take the course are in the top
25% of their class, but this is not required. I do not use a textbook. Lectures are rare but
are used when necessary. The majority of the information learned by the students is
through their own individual research, presentations by other students and laboratory
exercises. Objective testing is not used. Subjective and oral testing are incorporated for
evaluation. Students also demonstrate their knowledge through journal writing, research
papers, analysis of unknowns, role play and class discussions. Participation is expected and
evaluated.

This course taught in a rural school district located approximately 25 miles
southwest of Lansing. I have taught it seven times, from Spring of 1993 to Fall of 1995.
Students come from a variety of backgrounds. Some live and work on farms while others
have parents who are professors and doctors that commute to the city to work. Class sizes
range from 18 - 28 students. The administration is very supportive of this innovative and

unique course.

INTRODUCTION
SCIENCE BACKGROUND

Several commonly used forensic techniques can be used to Show how "scientific
tools" can be used for solving crimes. These techniques include microsc0py,
chromatography, spectrophotometry and electrophoresis. Many types of physical evidence
can be analyzed in the high school laboratory using these and other investigative
techniques. I will briefly review each technique/equipment used in the unit. Further
information can be found in Appendix A.

The microscope is considered the most important tool of the forensic scientist.
There are many applications of the microscope within the forensic science framework for
the high school laboratory. These include hair analysis, fiber analysis and document
analysis. Many high school students do not have a strong background in the use of the
microscope. Since much of forensic science is analyzed at the microscopic level this
section of the course is very important. See Appendix A - Section II for further information
on the microscope.

Chromatography, is a technique which can be used extensively in the high school
laboratory, however, many students never get a chance to use it in a meaningful situation.
I have used both paper chromatography and thin layer chromatography for analysis of inks,
lipstick dyes and drugs. See Appendix A - Section III for more information on

chromatography.

Spectrophotometry is another technique which is easily incorporated into the high
school curriculum and which has many forensic applications. Blood salicylate simulations
along with blood alcohol simulations both can be performed in the high school laboratory.
See Appendix A - Section IV for more information on spectrophotometry.

Electrophoresis is an especially exciting technique which has great utility in
forensic science. The students develop an appreciation of the complexity of DNA
fingerprinting while completing the electrophoresis lab. In addition, these activities
illustrate the integration of biology and chemistry. There are two electrophoresis labs in
this unit. The first utilizes dyes as models of DNA and allows the student to gain pipetting
experience before completing the second lab which uses DNA samples.

Many types of forensic evidence can be discussed and/or analyzed in the high
school classroom. I usually divide the types of evidence into two categories, class and
individual. See Appendix A - Section I for a detailed description of these classifications of
forensic science.

Class evidence is that type which can be associated with a group but not an
individual source. Examples include hair evidence, fiber evidence, blood and body fluids,
DNA and toxicology (drug analysis). Individual evidence is that which can be associated
with a specific source and includes fingerprints, shoeprint casts and questioned document
analysis.

Hair is an excellent type of evidence to use in conjunction with the microscope.
Not only does the student learn how to use the microscope and identify species of hair but
also learns the importance of careful sketching and detailed notetaking. I am especially
critical when grading this activity to ensure that the student understands the importance of

keeping a detailed and thorough notebook.

Textile evidence evaluation is another activity which has many applications in the
high school lab. The students continue to use the microscope yet begins to learn other
techniques. These include burning fibers and evaluating residue, odor and the effect of
vapors on litmus paper of the burned fibers. The fiber activities introduce the student to the
idea that it may require several types of lab tests to identify a fiber or evaluate any specific
piece of forensic evidence.

Blood and body fluids can and should be discussed in the forensic curriculum.
There are many applications of blood and body fluids analysis including ABO typing,
toxicology and DNA evaluation. An understanding of the ABO blood typing system is
useful for anyone whether interested in forensics or not because of the many applications
of the ABO blood type in all human lives. Lab activities using blood cannot be performed
in the high school lab due to blood product restrictions but there are many simulations
available. Body fluid simulations are also available for toxicology and drug evidence
discussions. All forensic units should include a detailed discussion of DNA and DNA
fingerprinting. If possible an electrophoresis lab of DNA should be included in this
section. I have incorporated DNA discussions and labs into this course and because high
school students, in general, have previously learned about DNA 1 have incorporate an
advanced molecular discussion.

There are several categories of individual evidence which I have incorporated
into this course. The students especially enjoy analyzing their own individual physical
characteristics. This is the area of the course they find to be the most "fun". Examples
include fingerprinting, making shoeprint casts and analyzing handwriting.

Fingerprinting analysis involves a minimal amount of preparation for the teacher

and promotes several days of firn and learning for the students. This activity has several

parts. These include inking a set of 10 fingerprints, determining their FBI classification,
dusting and lifting a print and making a 10 point print comparison. See Appendix B -
Section IX for the fingerprinting lab. The activity does not require many materials and
exposes the student to the individuality of the fingerprint.

That second type of individual evidence that is easily analyzed in the high school
lab is shoeprint casts. Again, there is a minimal amount of required materials and this lab
allows us to "escape" the classroom and go outside for a class period. The students also
end up with a "make and take" project.

The third type of individual evidence is document and handwriting analysis. These
labs require advanced preparation by the teacher (See Appendix B - Section V1] for the
document examination lab) but are enjoyable for the students. In addition, the labs provide
the students with another example of the difference between class and individual evidence.

Other types of evidence which I discuss in the classroom but which I have not
established labs for are Forensic Entomology, Forensic Anthropology, arson and glass and
soil analysis. I do feel, however, that all of the above have high school lab applications and
would provide future direction for continued improvement of this course.

Besides techniques and evidence, a thorough discussion of the crime scene should
be a part of all forensic lab units. Students need to have an understanding of all that is
involved in the collection and preparation of evidence to fully understand its application in

crime solving.

IO

STUDENT EXPECTATIONS
TECHNIQUES
Microscope
The students are expected to:
1. be able to properly use the microscope.
2. determine the overall magnification of each objective.
3. make detailed sketches of all microscopic observations.
4. discuss the difference between compound and stereomicroscopes.
Spectrophotometer
The student is expected to:

1. properly use and explain the use of the spectrophotometer.
2. read and record the absorbance of a sample.

3. determine the concentrations of serial dilutions.

4. use absorbance data to create a graph of absorbance vs. concentration.
5. use their graph to determine the concentration of an unknown.

6. explain how the spectrophotometer can be used to determine salicylic

acid concentrations and ethyl alcohol concentrations.

ll

Chromatography
The students are expected to:
I. explain the process of chromatography (stationary vs. mobile).
2. use paper chromatography to analyze water soluble pen inks.
3. use thin layer chromatography to analyze ball point ink dyes and
lipstick dyes.
4. perform and explain Rfcalculations and their use.
Electrophoresis
The students are expected to:
I. explain the electrophoresis apparatus and procedure.
2. perform electrophoresis on a variety of dyes and interpret gels.

3. perform electr0phoresis on a DNA sample and interpret gels.

12

STUDENT EXPECTATIONS
ANALYSIS OF FORENSIC EVIDENCE WITH LAB ACTIVITIES
Hair
The students are expected to:
I. analyze the morphological characteristic of hair from various animal
sources.

2. determine the animal source of an unknown hair.

Textile Fibers
The students are expected to:
I. analyze the characteristics of natural fibers.
2. analyze the characteristics of synthetic fibers.
3. compare and contrast natural and synthetic fibers.

4. use a variety of techniques to determine an unknown fiber type.

Blood and Body Fluids
The students are expected to:
1. Perform a simulated ouchterlony procedure to detennine whether
a stain is or is not human blood.
2. Perform a simulated urine analysis to determine the types of drugs
present in a sample.

3. Use electrophoresis to perform DNA fingerprinting.

l3

Lipstick Dyes
The students are expected to:
I. explain the chemical make-up of lipstick.

2. use chromatography to determine if One of several lipsticks matches that

of a suspect.
Ink Dyes
The students are expected to:
l. Analyze water based dyes using paper chromatography to determine
the identity of the pen used to write a threatening note.
2. Analyze ball point ink dyes using thin layer chromatography to
determine the identity of pen used to write a threatening note.
Fingerprints
The students are expected to:
1. ink a set of 10 fingerprints.
2. classify each of the 10 prints in #1 and perform an FBI primary
classification.
3. dust and lift a print.
4. compare a matching inked and lifted print to 10 points.
Shoeprints
The students are expected to:

I. make a plaster cast of their own shoeprint.

2. explain why shoeprints are individual evidence.

l4

Questioned documents
The students are expected to:
1. match the writing on a suspect note to a known exemplar.

2. perform a tracing and a forgery on a friends signature.

15

STUDENT EXPECTATIONS
ANALYSIS OF FORENSIC EVIDENCE WITHOUT LAB ACTIVITIES

Forensic entomology
The students are expected to:
I. explain the use of entomology in solving crimes.
2. give an example of entomology use in crime solving.
Forensic anthropology
The students are expected to:
I. explain the use of anthropology (bone structure) in solving crimes.
2. give an example of anthropology use in crime solving.
Arson
The students are expect to:
I. explain the chemistry of fire.
2. discuss various types of arson accelerants.
3. explain how accelerant analysis can be used in solving a crime.
4. explain how arson investigators determine the cause of a fire.
Glass and soil evidence
The students are expected to:
I. explain why glass and soil evidence are both class evidence.

2. explain why William Kennedy Smith was acquitted of rape charges.

l6

STUDENT EXPECTATIONS
OTHER ACTIVITIES RELATED TO FORENSIC SCIENCE

The Crime Scene
The students are expected to:
1. develop a thorough understanding of all parts of the crime scene
including preserve and protect, and maintaining a chain
of custody.
2. participate in a crime scene role play activity. (See Appendix A -

Section I for more details).

Case Readings
The students are expected to:
I. participate in the reading and analysis of the Lindberg Kidnapping
case.
2. participate in the reading and analysis of the Wayne Williams

C386.

IMPLEMENTATION

The decision to teach this unit as a semester course in our science curriculum was a
fairly easy one to make given the enthusiasm and support on the part of the many people
involved. First and foremost I questioned my Chemistry 1 students about their opinions for
a new upper level science course. The basic concern of the students was that it not be
"another lecture course", that they could learn science by application and that they could
have fim. Second, I talked to the other staff members in the department and they were
100% supportive of an applied type of class and finally, the faculty at Michigan State
University were willing to help in any way.

The labs and activities which I have incorporated are a combination of activities
fiom a variety of sources. Some remain as they were written in their respective lab
manuals. Many have been adapted from a variety of lab manuals for specific use in my
classroom and a few I have designed myself. Specifically, the activities which I designed
include the suspect note investigation of the Paper Chromatography lab, Crime Scene A
and Crime Scene B of the Microscope Lab, the crime scene investigation in the
Examination of Hair by Light Microscopy lab, the Carpet Sample Lab, the crime scene in
the Lipstick Chromatography lab, the Determination of the Peak Absorbance of a
Substance Using Visible Spectrophotometry lab, and the Crime Scene Role Play activity.
Activities which I did not design but revised for use in my classroom include the Practice

in the Use of the Microscope lab, Examination of Hair by Light Microscopy, Analysis of

17

18

Fibers, Determination of Lipstick Dyes Using TLC, Analysis of Inks by Thin Layer
Chromatography, Identification of Salicylates in Blood by Spectroscopy, The Alcohol
Breathalyzer Test: A Laboratory Simulation, and the DNA Electrophoresis lab. I will be
discussing each of them in the order that I use them in my classroom.

In addition, I have incorporated many methods in my unit including lectures,
projects, audio-visual aides, current event topics, case readings and role play activities.
Basic class requirements per nine week (two nine week marking periods per semester)

marking period are listed below:

Attendance and participation 200 points
Notebook 200 points
Project 200 points
Lab exercises and unknown solutions 200 points
Crime scene role play 100 points

(second marking period only)
Total 900 points
First marking period has approximately 800 points.

Each students is required to keep notebooks of all class activities. Included in this
notebook are lecture notes, handouts, case reading analysis, current event discussions and
lab activities. The notebook must be in chronological order and detailed. I tell the students
to pretend that they are "real" forensic scientists and could be called to the witness stand at
any time. Their notebook may be their only recollection of the evidence involved and
therefore should be as complete as possible.

Attendance and participation is another important aspect of the course. I feel that

in order to successfully understand and complete the many classroom activities the student

19

must be in class and participating. Copying of other students lab sheets is not acceptable.

The student must complete a project each marking period. For the first nine weeks
this is a group project. The second nine weeks‘ project is individual. The group project
usually involves writing a research paper, developing a visual aide and making a
presentation to the class. Examples of research topics have included evidence investigation
(fibers, DNA, blood typing) and case readings and analysis (Manson murders and the
John Wayne Gacy trial). No two groups can use the same topic and therefore each group
learns from the presentations of other groups. In general, the students do a thorough job on
their projects. I have seen some very unique and creative presentations.

Individual projects are usually designed by the students themselves. Current event
topics have been a favorite choice. In this instance students must follow current event
situations involving crime and criminal evidence and write an overview of the situations.
Other choices have been critiques of suspense or thriller novels and writing their own
crime story.

The fourth area students are graded on is their laboratory write-ups and unknown
investigations and evaluations. They must justify their conclusion regarding their unknown
with their laboratory procedures.

Lastly, they are graded on their participation in the crime scene role play activity
during the second marking period. We begin this activity after the students have
completed a majority of the labs.

For the final exam I usually put the students on the witness stand with their
notebooks. I randomly ask them questions regarding the semester work which they should
be able to answer correctly if they have done a good job on their notebooks. They are

graded on their responses.

20

COURSE OUTLINE

1. Lecture topics
A. The Crime Scene
1. outline
2. guest speaker
a. crime van
b. forensic entomology
c. forensic anthropology
d. interrogation
3. crime scene role play
B. Hair morphology and analysis
C. Fiber morphology and analysis
D. Document examination
E. Fingerprint exarrrination
F. Toxicology
G. Blood and Body Fluids
H. DNA

21

II. Group Discussions/ Work
A. Current Events
1. Topics brought up daily and evidence discussed
2. Individual project - second nine weeks
B. Review of past cases
I. Lindbergh kidnapping case
2. Wayne Williams murder trial
3. John Kennedy assassination
III. Laboratory Exercises
A. Paper chromatography
1. Water soluble ink analysis
2. Toxicology
B. Hair Analysis
C. Fiber Analysis
D. Thin Layer Chromatography
1. Lipstick Analysis
2. Ink Analysis
E. Document Examination
F. Fingerprint Evaluation
G. Ouchterlony - blood analysis
H. Spectrophotometry
1. Graphing exercise
2. Testing for salicylates in blood

3. Breathalyzer Simulation

22

I. Electrophoresis
1. Dyes
2. DNA
J. Footprints
IV. Audio-Visual
A. 118 Green Street - NOVA program
B. Sherlock Holmes videos
V. Field trip
A. Michigan State University forensic laboratories
B. Michigan State University glass blowing laboratories
C. Michigan State University Museum
VI. Guest speakers
A. Detective
B. Arson investigator
C. Michigan State University forensic scientist
D. DARE officer
VII. Evaluations
A. Lab unknowns
B. Detailed Journal
C. Projects
1. Group - first nine weeks
2. Individual - second nine weeks
D. Attendance and daily participation

E. Crime scene role play

23

F. Final exam
1. Simulated jury trial

2. Individual expert questions

24

LABORATORY EXERCISES

BARERCHRQMAIQGRARHY

Paper chromatography is an excellent lab to use at the very beginning of the
semester. I have adapted it for use in my classroom from a high school chemistry
laboratory manual. See Appendix B - Section I for a detailed write-up. It serves several
functions. First, because the students are required to use it to solve a crime, it piques their
interest in regards to the rest of the semester. Second, chromatography has a strong
application to biochemistry and forensic science and it requires the students to begin
thinking at the molecular level. Third, the students are always amazed at the results.

This lab is based on the fact that black, water soluble inks are made up of different
combinations of colored ink dyes. Different companies use different combinations and
therefore by analyzing a series of "known" ink pens with chromatographic methods a
student can identify the pen that an "unknown" ink mark was made by.

The students not only have to carefully follow directions in the lab but they also
have to figure out a way to analyze the unknown ink. This ink is written on a piece of
notebook paper. The students have to determine how to transfer that ink to filter paper in
order to chromatograph it. Finally, one of the "known" pens is a permanent marker which
is insoluble in water. This requires them to evaluate why the one dot didn't move but the

others did.

25

Overall, the lab is outstanding. It relates to real "forensic" work. It includes critical
thinking and evaluation. 1 usually begin discussing the techniques of chromatography after
this lab is completed and refer back to it. The lab can be completed in two 50 minute class

periods.

W

The microscope is used extensively in forensic science and many people believe it
to be the most valuable tool. The students, therefore, need to have a thorough
understanding of it's make-up and use. This lab requires the student to learn and use both a
compound microscope and a stereo microscope. I have adapted this lab for my classroom
fi‘om a forensic science lab manual. See Appendix B - Section II for the lab write-up.

The students are required to look at and sketch a letter from the newspaper using
both types of microscopes. They then make a comparison between the two images. Upon
completion of this they are given two crimes to solve. One requires the analysis of paper
matches found at a crime scene. The other involves a college student who is accused of
cheating on a test. The students analyze the ink samples on the test. Each student is given
their own unknown to solve. They must have a thorough understanding of the lab
procedures in order to identify their unknown. Students are evaluated on their final’
unknown determination and on their lab write up. This lab is very effective because of it's
ability to introduce the students to the microscope and incorporate the critical thinking

aspect of crime solving. The lab can be completed in two 50 minute lab periods.

W

26

This lab is a combination of several hair identification labs. I have incorporated
those procedures which seem to work the best into one lab. The students are required to
analyze and evaluate four types of animal hair, human, dog, cat and horse. This analysis
includes both gross and microscopic examination of the hair. In addition, the students are
given trace hair evidence which was taken from a crime scene and are asked to determine
its origin.

The students are always amazed at their ability to detennine the species from which
their hair sample came. They also enjoy seeing all of the "junk" (hairspray, gel, etc.) that is
clinging to their own hair. I especially like this lab because it requires the student to use the
microscope, note details/Critically observe what they are seeing and prepare detailed
sketches. The average high school student does not get a lot of experience doing this. This
lab can be completed in four 50 minute lab periods. See Appendix B - Section III for a

detailed write-up.
ANALYSISDEEIBERS

As with the hair analysis lab, the fiber lab is a combination of parts of several labs.
It continues to give the student experience using the microscope and utilizes other technical
skills as well. Besides microscopic evaluation, the students analyze the effect heating the
fibers has on litmus paper, the residue left from burning the fibers and the solubility of the
fibers in different solvents. The students are required to evaluate the difference between

natural and man-made fibers based on all of the above characteristizations.

27

This lab requires a great deal of reinforcement and/or encouragement by the
teacher. It takes one to two weeks to complete and sometimes can get monotonous for the
student. The students do Ieam a great deal from this lab, however. In addition, it helps the
student to see an connection between chemistry and biology. Though this is not a favorite
lab for the students they do comment on the amount of knowledge they gain from it.

See Appendix B - Section IV for the lab write-up.

W

At the conclusion of the hair and fiber labs each student is given a carpet sample to
investigate. Imbedded in the carpet are several hair or fiber samples of one type. The
student must find the samples and analyze them according to the procedures in the
previous two labs. They must determine the type of hair or fiber they have and give a
detailed explanation of their analysis.

This activity incorporates both the hair and fiber labs. The students each have their
own unknown so they must rely on their own knowledge to solve the problem. This
activity can be completed in one 50 minute lab period. See Appendix B - V for the lab

write-up.

28

WW
CHROMATOGRABHX

This lab is an introduction to a more technical type of chromatography used by the
forensic scientist. The day of this lab the students enter the classroom and find a message
scrawled across the window which was written using red lipstick. I tell them that I have
confiscated the lipsticks from three teachers who I suspect wrote the note. They are
required to analyze the known lipsticks and the lipstick from the window using thin layer
chromatography.

This lab is an excellent teaching tool for several reasons. First, it allows for a
discussion of lipstick components. Many students find it disgusting to learn that they are
putting metals mixed with animal lipids onto their lips when they apply lipstick. Second,
because the solvent used has an especially bad Odor we perform the chromatography in the
fume hood. The students always enjoy "working in the hood". Finally, with the
determination of Rfvalues for the resulting bands a true relationship between mathematics
and science is established. This lab can be completed in two 50 minute lab periods.

See Appendix B - Section VT for the lab write-up.

29

Throughout the first marking period I periodically collect writing samples from the
students. The samples are dictated to them. Sometimes I dictate fast, sometimes slow and
sometimes I ask them to try to disguise their handwriting. I then select one of the samples
from each student to be a questioned document. I also select four other samples per
questioned document, one of which was written by the same writer as the questioned
document and three which have similar writing but are not exact. Each student gets one of
these sets and no student gets their own writing for their questioned document. The student
must determine which of the four samples was written by the same person as their
questioned document. They must match the two documents with ten points based on the
characteristics which were talked about in lecture.

The students usually enjoy this activity. They are always surprised that even
though they tried to disguise their writing some characteristics still come through. The set
up for the lab requires a lot of time but it is an effective way of showing the individual
nature of handwriting. This lab requires three 50 minute lab periods to complete.

See Appendix B - Section VII for the lab write-up.

30

W

This lab is used in conjunction with the Questioned Document lab. Analyzing the
inks are an important part of questioned document evaluation. The lab is very similar to
the water soluble ink lab but utilizes organic solvents and the techniques of thin layer
chromatography.

As with water soluble inks, ball point inks have their own unique components. The
band patterns which result from this procedure are more complex than the lipstick analysis
chromatography. The lab is solved by a comparison of Rfvalues. See Appendix B.

The students again get the experience of working in the fume hood and of
incorporating mathematical concepts into science. The lab is easy to follow and complete
and I feel it is effective in portraying the unique components of different pen types.

This lab requires two 50 minute lab periods to complete. See Appendix B - Section V1] for

the lab write-up.

WW

Fingerprints are everywhere. Students have seen and read about fingerprint
evidence over and over. Rarely, however, do they have a biological and physical
understanding of fingerprints.

This lab requires them to do several activities with their own and each others

fingerprints. They first must ink and roll a partners set of ten prints on an FBI card. They

31

then must classify all of their own prints as to print type. From this determination they can
then determine their FBI primary classification. In addition, they are required to dust and
lift a print. Finally, they must identify their own thumb print from a sheet of approximately
25 (their classmates) thumb prints. They must match this print to an inked print with 12
points.

Many students say this is their favorite lab. All of the evidence is theirs and they
are amazed at how unique they are. They learn a lot about comparison techniques and the
detail involved in some forms of science. This lab requires three to four 50 minute lab

periods. See Appendix B - Section IX for the lab write-up.

SHQEERINIS

The shoeprint lab is another way to demonstrate individual evidence. The lab
involves taking the students outside and making plaster casts of their shoeprints. The casts
are then brought inside and I demonstrate making ink impressions with one of the prints.
The students determine that even if they have the identical type of shoe as another student
their shoeprint is different.

I do not have each student ink their own cast. This simply gets too messy. In
addition many of the students want to take their print home. This would be impossible if
the cast was inked. This lab can be completed in one to two 50 minute lab periods.

See Appendix B - Section X for the lab write-up.

32

W

Drug analysis in a high school classroom is impossible so 1 use this simulation
instead. This lab involves paper chromatography and food coloring. It is very similar to
the other paper chromatography lab we do except that we use paper chromatography paper
instead of filter paper. The food coloring portrays urine samples with drugs in them. The
students analyze the different colors which represent various drugs and base their
conclusion on the results. This lab can be performed in one hour. A possible improvement
to this lab would be to use over-the-counter drug preparations instead of food coloring. See

Appendix B - Section XI for the lab write-up.

W

Blood products are often found at the crime scene but the analysis of blood is not
allowed in the high school laboratory. This technique involves the chemical simulation of
human blood and human blood antiserum. The lab includes the making of ouchterlony
media, preparing and loading the wells and observing precipitin reactions. It fits into a
blood and body fluids discussion. After this activity I usually discuss A-B—O blood typing
procedures. Overall, the lab is a good experience for the students. The results sometimes
are vague and difficult to interpret, however. One possible solution would be to use horse
blood and buy anti-horse serum. The test could then be run using real blood. This lab can
be completed in two 50 minute lab periods. See Appendix B - Section XII for the lab

write-up.

33

l {ulkalOkO ' at a: 01-;\ In . ' I

This lab is performed before any other labs are done with the Spec 20. The
students are required to prepare a series of dilutions using methylene blue stain. They then
determine their % transmittance and absorbance of each dilution at varying wavelengths.
After plotting this data they are able to see that there is a common absorbance peak
between each concentration. This is the maximum absorbance.

The major drawback of this lab is the time is takes to complete. At least three days
should be allowed for completion. The tubes must be covered with parafilrn and wrapped
in foil if left overnight. The results are very good however and the students begin to
understand how wavelength values are determined. See Appendix B - Section XIII for the

lab write-up.

I. \II alOk0 :. I; It s 3 00.3 ' It. 0'

The use of a spectrophotometer at the high school level is unique for many
students. Several of my former students have returned from college and told me that they .
were the only ones in their college chemistry class who knew how to use this instrument.
The drawback of Spec 20 labs for me is the school does not own them. The only way for
me to do the labs is to rent and transport the machines.

Students identify blood salicylate levels in a simulated blood sample. The lab

requires the students to make a series of ferric nitrate/salicylic acid dilutions, determine the

34

concentrations of each dilution, test them for percent transmittance, prepare a calibration
curve and determine the concentration of an unknown salicylic acid sample. After
successful completion of this procedure they are given a crime scene situation and must use
their information from the first section to complete the second.

The students learn how to correctly plot data and then use this data in this lab
exercise. The lab works well. It takes approximately two 50 minute lab periods to

complete. See Appendix B - Section XIV for the lab write-up.

.
C
D
.
C
.
I.
'0
D
C
I
(I
D

I
'I
C
'-
I
.
r.
.

SC;

The students find this exercise, which also uses the Spec 20, to be especially
interesting because of the widespread use of the breathalyzer test. The students make a
series of ethyl alcohol/potassium dichromate dilutions of known concentration, plot their
data and then determine the concentration of an unknown ethyl alcohol sample.

The procedure is very simple to follow and the results are consistent. Potassium
dichromate is a suspected carcinogen and the students need to know to use caution when
working with the chemicals. The concentration of the chemicals they work with are low
(compared to techniques used in their previous chemistry labs) and there is a greater
chance of experimental error with this lab due to this. This lab takes approximately two 50

minute lab periods to complete. See Appendix B - Section XV for lab write-up.

35

W

This lab is a great introductory lab to electrophoresis because of the low cost of the
dyes used. It gives the students practice using micropipettes which is helpful when we do
the DNA electrophoresis lab.

The students are required to make their own gels, fill the wells and electrophorese
the dyes. In addition they are given a mixture of dyes as an unknown and they are required
to separate these using electrophoresis. From the electrophoresis results they can determine
the components of the unknown dye mixture.

This is an excellent laboratory exercise. The results are always consistent. The
students develop an appreciation for the fact that molecules can be either positively or
negatively and that they can separate mixtures based on this property. The lab usually takes
two 50 minute lab periods to complete. See Appendix B - Section XVI for the lab

write-up.

DNAELECTRQBHQRESIS

With the high profile use of DNA fingerprinting in crime solving today an
understanding of the process is useful for all of us. At this point in the class the students
have developed an understanding of correct experimental procedures and are ready to

work with a complicated and expensive molecule like DNA. Again, they prepare their

36

own gels, load the wells with the sample and electrophorese them. In addition, they must
stain and de-stain the gels in order to visualize the DNA fragments.

The lab is very simple to follow, can be completed in two lab periods and gives the
student a basic understanding of DNA fingerprinting. See Appendix B - Section XVII for

a detailed lab write-up.

37

OTHER ACTIVITIES
' SEEAKERS

1 usually have three to four speakers come into my classroom each semester. This
allows the student to see individuals who are currently working in forensic related fields.
Types of careers presented include detectives, DARE officers, arson investigators and
forensic scientists.

The Livingston County Sheriffs Department has several detectives who are willing
to speak to my classes. The detectives usually bring the crime van to the school so that the
students have an Opportunity to observe pieces of equipment and other items which are
taken to crimes scenes. In addition the detectives will talk about criminal cases, evidence
and areas of investigation. I usually ask them to talk about the areas of evidence which we
do not cover in class like forensic anthropology, forensic entomology and autopsies. A
discussion of what happens in an interrogation room is also a topic of interest for the
students.

The DARE ( Drug Awareness Reinforcement Education ) officers also are
commonly seen in our schools and are willing to talk to the students. They will usually
discuss the drugs of choice in the area for students their age and the dangers of these drugs.
They will also discuss what the area police departments are doing to combat the drugs and
some of the current drug laws. Many times they will drive a very expensive automobile to
the school and explain to the students that it was confiscated in a drug raid and now

belongs to the department.

38

Arson investigation is another area of interest for my students and there is
an investigator in Livingston County who will speak to the students. This individual does
an excellent job of teaching the students that fire and arson are chemistry. In addition he
discusses how fire investigators can determine the origin of a fire by burn patterns on the
floors, walls and ceilings. He also shows them how light bulbs can be especially helpful in
detennining fire origins because of the many components which burn at very different
temperatures. Students find this discussion very interesting and informative.

Dr. Jay Siegel, professor of forensics at Michigan State University is willing to
speak to the students, also. The students rarely have had any exposure to college
professors and therefore find this lecture to be especially interesting. He is able to portray
to the students the fact that professors are real peOple. Dr. Siegel speaks to the students as
adults and this is very much appreciated by them. He gives many examples of forensic
science use in crime scene analysis. The students gain a lot of insight into forensic science

from this presentation.

39

EIELDJ'RIES

I always try to take the students on a field trip to Michigan State University. The
faculty are very willing to give presentations and help with this in any way. Areas which I
have found to be especially interesting are tours of the chemistry and forensic laboratories,
tours of the glassblowing laboratories, greenhouse tours and museum tours.

Dr. Siegel will usually give the forensic science and chemistry lab tours. He shows
them the many advanced pieces of equipment used in the forensic lab. They probably
would not have this opportunity if not for the willingness of Dr. Siegel to help. In
addition, the students get to see what a college laboratory and lecture hall look like. For
many of them this is the first time they have ever been in a college classroom.

The glassblowing laboratory is usually the second stop on our visit. The students
get to participate in the art of glassblowing. They are very enthusiastic about this tour and
talk about this for weeks.

The day usually ends with a visit to either the greenhouses or the museum. Both
toms are outstanding. The diversity of plants which can be found in the greenhouse is
always a point of discussion after the tour. Several students have commented on their
intent to go into botany after this tour. The museum is also a very interesting tour. We
usually get the opportunity to visit the "behind the scene" libraries where many of the
research animals are kept. The students enjoy seeing drawer after drawer of preserved
animals. Occasionally the students also get to observe the Dennestids lab. This has a great
application to forensics anthropology and again is a great area of discussion after the field

trip.

40

W5

Many of the crime videos available are simply too graphic to be used in a high
school classroom. However, two that I have found to be useful are W by
NOVA and Sherlock Holmes videos.

The video W (NOVA) is a great representation of the microscopic
world. The students develop a respect for the microorganisms around us from this movie.

I usually will show this during the hair and fiber laboratories.

Sherlock Holmes videos can be shown anytime. Some of them tend to be more
explicit than others and should be screened before showing. The videos, however, do have
a great deal of evidence. Most of this evidence can be seen with the naked eye but only the
creative expert thinks to use it. The students begin to develop the idea that much of science
is actually a creative thought process and that higher level thinking can help them evaluate

many situations.

41

CASEREADINGS

I usually have the students read at least three case readings. The choices I use are
the Lindbergh kidnapping case, the Wayne Williams murder case, and the John F.
Kennedy assassination. The students have usually only heard of the latter case but do
develop an interest in the former cases once they read them.

I like to use the Lindbergh case reading because of the extensive use of the
microscope in examining the evidence. After reading this case the student learns how
valuable a tool the microscope is. They also find it very interesting that a person can be
such an expert in a subject that the majority of the population knows very little about.
Besides talking about the crime I use this case to talk about how important it is to become
an expert in the career they choose to undertake.

The Wayne Williams case reading is very long and sometimes difficult to
understand. However, it does show the student how class evidence can be used in
conjunction with other evidence to convict an individual.

The John F. Kennedy case reading allows the student to evaluate what they feel
really happened. With so many conflicting stories surfacing about this assassination the

students get the opportunity to look at the evidence and develop their own conclusion.

42

ROLELELAY

CRIME SCENE

One of the favorite activities of the class is the crime scene role play. The class is
divided into two parts, group A and group B. Group A designs a crime for Group B to
solve and vice versa. The crime must be well thought out with at least three pieces of
evidence involved. Every individual in the group must have a part in the crime even if it is
a minor one. All members must have a thorough understanding of their own part, their
own crime and the other members' parts.

After the initial design phase one of the groups is chosen to set up their crime
scene. While they are doing this the other group must prepare to solve the crime. Each
member of the solving group must have a role. Roles include first officer at the scene,
chief investigator, detective, note taker, sketch artist, photographer, news paper reporter,
interrogator and forensic scientist. They must know the requirements of their part and be
able to perform the part well.

During implementation I watch each member of the role play carefully. The
students are graded on their set-up and their performance. For example, if Detective A
forgets to bring his crime scene kit (tweezers, gloves, evidence bags etc.) to the crime
scene, he will have points taken off his total score. Also, if suspect C forgets that she was
actually at the neighbors house during the crime not in the neighborhood bar she will have

points taken off her total score. The students are expected to have a thorough

43

understanding of their part in the role play and be prepared to cany it out correctly. After
this case is solved the two groups reverse roles and the second crime is set-up and solved.
This activity is outstanding. The students really have to become critical thinkers to
solve the crime. They get frustrated with each other and usually have to go back to square
one and start over. Team work becomes very important to them and they get disgusted
when one member does not do their share. I feel this activity is as beneficial to them as the

labs are.

EVALUATION

The material presented in this unit is different fi'om the material presented in any
other class we offer at our school as it includes many activities that are subjectively
evaluated. Therefore, pre and post testing is not very usefirl. I have given
pretests before and the students usually indicate that they do not have any or very little
knowledge of the topics we discuss. Student interviews and discussions, however, seem to
be an effective form of evaluation.

There are several different aspects of the class that the students have indicated as
being "what they liked most". These include being able to work at their own pace, being
able to socialize with other students while doing school work, less amount or time spent in
lecture, doing lots of labs, learning material that they can apply to real life situations and
specific areas that interested them.

For many of the lab activities I give the lecture presentations, a pre-laboratory
discussion, and a time line for completion. The students then can work at their own pace.
Students know that if they waste a lab day that they either have to work at twice the pace
the next day or come in after school to make up the lost time. If they get done before the
due date then they can use the time to work on their nine weeks project. This is the only
time that they are given in class to work on the project. The students appreciate this sense
of trust. Some of them learn that they need a more structured environment and ask to be

given more deadlines, but the majority of them get the work done when it needs to be done.

44

45

This type of environment promotes a lot of socialization among the students. They
really become a cohesive unit. The class is only offered to seniors and therefore this may
be one of their last chances they get to spend time with other students. I, also, enjoy being
able to interact with students in a less formal atmosphere.

The minimal amount of lecture is also appreciated by the students. My goal with
lecture is to introduce as much material as I can while using a minimal amount of class
time. In many instances I give them written material instead of lecture. Those who have
questions can meet with me individually. The majority of the students are high achievers
and they make sure they get the information they need to get the job done.

Students appreciate the fact that they are being taught a science that they can see
has a direct application to their lives or at least lives they see in the media. Many of the
comments I hear deal with the fact that they could understand the material because they
heard about it everyday in the news. They enjoyed knowing just a little bit more than the
average citizen.

Students also enjoy doing labs. They do, however, have their definite likes and
dislikes. Fingerprinting tends to be a favorite. They magnify their print and locate many of
the points of comparison. In addition, viewing the fingerprint under the stereo microscope
brings about a lot of enthusiasm. "Wow, you can actually see the oils on there!" The fiber
lab tends to be one of the least favorite. Many factors contribute to this. The lab takes
about two weeks to complete and therefore gets monotonous. The fibers have a lot of
unique smells which tend to turn the stomachs of a few and the difficulty in manipulating

the fibers gets frustrating.

46

Some of the comments from the Fall 1995 semester interviews include:

"Chemistry H allows students to see how science works in real life making the
educational experience much more exciting."

"I feel I have learned more in this class than any other."

"I like doing the labs because as we do it we are learning and don't even know it."

"It was a great semester. It is fun and you learn."

"We learned alot of important things and we also had firn."

"I liked it and I did actually learn something."

"I enjoyed the openness between the teacher and students."

"I learned plenty and I'm sure other people will too."

"Chemistry II encourages group work, open thought and discussion and has much
to offer in the ways of forensic science."

In addition to class discussion I asked the students to evaluate their knowledge on a
variety of topics. They were instructed to address this both before taking and after
completing the class. They graded their knowledge on a scale of l - 5 with 1 being they
knew nothing about the subject and 5 being they knew a lot about the subject.

Twenty three students completed the questionnaire. The average results are as follows.

47

Table 1
Percent change of a variety of studied topics.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BEFORE TOPIC , AFTER % CHANGE
2.78 light microscopy 4.48 61%
1.43 stereo microscopy ; 3.48 143%
1.96 chromatography (general) f 4.34 166%
1.78 paper chromatography ' 4.34 144%
1.61 thin layer chromatography a 4.09 g 156%
1.48 water based ink dyes l 4.09 176%
1.48 ball point ink dyes f 4.26 188%
1.48 lipstick dyes i 4.26 188%
2.13 crime scene procedures J 4.71 120%
2.35 arson ! 4.01 70%
2.57 DNA evidence l 4.04 61%
2.57 blood and body fluids i 4.31 67%
1.57 hair evidence ' 4.39 180%
1.43 fiber evidence 4.22 194%
2.52 drug categorization i 4.09 62%
2.74 drug laws T 4.13 51%
2.31 fingerprinting l 4.78 108%
1.31 forensic entomology l 3.31 154%
1.31 forensic anthropology T 3.04 134%
1.51 document evaluation 5 4.17 178%

 

 

 

 

 

The table above shows how students rated their knowledge on a variety of topics before and
after completing the unit. The scale used is 1 = very little knowledge, 5 = a lot of knowledge

The data was obtained and compiled during the Fall 1995 semester.

48

Table 2
Before and after comparison

 

BEFORE

AFTER

 

forensic entomology

forensic anthropology

 

forensic anthropology

forensic entomology

 

stereo microscopy

stereo microscopy

 

fibereddence

arson

 

water based ink dyes

DNA evidence

 

ball point ink dyes

thin layer chromatography

 

lipstick dyes

water based ink dyes

 

document evaluation

drug categorization

 

hair evidence

document evaluation

 

thin layer chromatography

drug laws

 

paper chromatography

fiberewdence

 

chromatography (general)

ball point ink dyes

 

crime scene procedures

lipstick dyes

 

 

fingerprinting blood and body fluids
arson chromatography_(_general)

 

drug categorization

paper chromatography

 

blood and body fluids

hair evidence

 

 

DNA evidence light microscopy
drug laws crime scene procedures

 

 

fight microscopy

 

fingerprintingr

 

 

Table 2 lists the categories in order of least knowledge to most knowledge about the tOpics
both before and after the unit. For example before the semester the students rated their

‘ knowledge lowest in the category of forensic entomology and highest in light microscopy.
After the semester they rated their knowledge lowest in forensic anthrOpology and highest

in fingerprinting. The data from Table l was used to make this table.

Table 3
Percent change

Table 3 shows the percent change in knowledge after the completion of the unit listed in

order from least to most change. The data from Table l was used to make this table.

49

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TOPIC % CHANGE
drug laws 51%
DNA eu’dence 61%
light microscopy 61%
drug categorization 62%
blood and body fluids 67% ]
arson 70% T
fingerpri nti ng 108% |
crime scene procedures , 120% l
forensic anthropology I 134% l
stereo microscopy l 143% i
paper chromatography 1 144%
forensic entomology ‘ 154% '
thin layer chromatography 156%
chromatography (general) 166%
water based ink dyes 176%
document evidence 178% .5
hair evidence 180% I
lipstick dyes 188%
ball point dyes . 188%
fiber evidence 1 194%

 

 

50

From this analysis 1 determined that the students feel that they come to the class
with their greatest knowledge in light microscopy, drug laws and DNA evidence.

The students do use the light microscope in other required science courses and they feel
confident with this knowledge. In addition, I feel that the increased drug awareness
programs in our school gives them exposure to the current drug laws. The class (Fall
1995) which was surveyed coincided with the conclusion of the OJ. Simpson murder trial.
The students had a lot of exposure to DNA due to the trial publicity.

The three categories in which the students have the least knowledge both before
and after taking the class are forensic entomology, forensic anthropology, and stereo
microscopy. The only exposure they get regarding forensic entomology and forensic
anthropology is from the detective who speaks to the class. The stereo microscope is used
for only one lab and could explain this lack of confidence with it.

In terms of percent change the students felt they learned the most from fiber
evidence, ball point dye analysis and lipstick dye analysis. These were ranked by them
very low as to pre-class knowledge. The lowest percent change occurred with light
microscopy, DNA evidence and drug laws. Again this coincided with the three areas they
felt most confident in when coming to class.

Comments that I have heard from alumni who have gone onto college include:

"I was the only one in my Chemistry lab who knew how to use the Spec 20."

(Spring 1993)

"We had to do thin layer chromatography in our chemistry lab. Not many other
students knew how." (Spring 1994)

"My college professor wants more information on your class. He thinks its great

and is envious that you get to teach such a fun class." (Spring 1993)

51

"I've signed up for criminalistics as a career. Thanks for all you did." (Fall 1995)

DISCUSSIONS AND CONCLUSIONS
COURSE CONTENT
HISTORICAL PERSPECTIVE

As expected, the course has changed in many ways over the four years (seven
semesters) that I have been teaching it. New labs have been added and other labs have
been eliminated. In addition, writing assignments have been incorporated and lecture
topics increased.

The first time I taught the course was in the Spring of 1993. This was prior to my
thesis research which was in the summer of 1993. Therefore, I had not had the opportunity
to thoroughly investigate the topic. Dr. Siegel had given me several topics and a good start
but the semester was far from where it is today. Lab activities that first semester included
hair and fiber analysis (though they only included microscopic examination), shoeprints,
blood analysis for salicylate content (SPEC 20), fingerprinting, chromatography, and DNA
labs. The labs took about twice as long as they currently do to complete due to my
inexperience. Lecture topics were more limited also. I spent more time discussing the
crime scene and less time discussing physical evidence. Arson, questioned documents,
forensic entomology and forensic anthropology were not discussed. The students during
that first semester did not have to complete any writing assignments besided their
notebooks. In some ways, the students learned more, this semester, simply because they
were learning while I was learning. They would help me figure out ways to make a lab

better (covering the Spec 20 tubes with foil if they needed to be stored overnight) or to

52

53

decide that this activity just isn't going to work (hair penning). In addition, they gave me
ideas as to areas of forensic science which they found to be most exciting (fingerprinting).

The summer following this first semester was my research summer. I got the
chance to redesign the course. Changes were made in every aspect of the course. Labs,
lecture topics and writing assignments were expanded.

I have found that high school students do not get enough experience writing
research papers for non-English classes. Therefore, I incorporated a research paper into the
course. The students are required to write a three to five page research paper on a type of
evidence using at least three sources. Upon completion they are required to do a class
presentation about their type of evidence. This activity has been a positive addition to the
course. The students are able to incorporate their own talents into the project and then
"teach" the topic to their peers. I have had students make videotapes and posters and role
plays as part of their presentations. Other students have contacted experts in their topic
areas and brought them in to speak to the class. This activity has promoted responsibility
and creativity.

Other writing activities that I have tried have not been as successful. One group of
students was asked to write a murder mystery. They were required to incorporate a
minimum of three pieces of physical evidence and other guidelines were given. However,
it was difficult to get a good project out of all of them. Some students just don't have the
talent to be creative writers. Another writing activity included reading a mystery novel and
writing a paper about the evidence used in the novel to solve the mystery. The students, in
general, liked this activity but it was difficult to find mysteries which did not include a lot
of sexual and violent material. The last type of writing assignment which I am still using

but which needs redesigning is a current events project. The students are required to find

54

ten current event articles related to crime and physical evidence and write a one page
evaluation of each. The activity, hOwever, is not structured enough and many students wait
until the last week to find all ten. They usually do not do a good job when they
procrastinate like this. I am continuing to work on this activity and plan to use it again.

Lab activities which have been added and/or changed are many. I have tried
several different hair analysis labs and have found some to be successfirl and others not so
successful. In general, microscopic examination of hair strands and hair casts work well.
However, some techniques just don't work. One hair lab called for the student to "perm"
hair strands and evaluate what perm solution does to the hair strand. The lab itself worked
but we were left wondering what the real purpose was. I haven't used the lab again. Fiber
labs, like hair labs, are fairly simple to incorporate and there are a lot of activities dealing
with fibers. Over the years, I have tried water retention activities, analysis of knit structure
and fiber content labs but eliminated them due to time constraints. Document analysis labs
were added the second year and have been a positive addition to the course. I plan to keep
adding and changing the labs as new ideas become available.

Lecture topics are continually increasing and changing also. This last semester was
the first time I lectured on forensic entomology, forensic anthropology and drug
categorizaiton. In addition I've had an arson investigator as a guest speaker during the last
three semesters.

The class content has improved since the Spring of 1993. This content
improvement is positively reflected in the students knowledge (evaluated during class
discussions), lab journal and writing activities. Discussions at the conclusion of the course
include more detailed scientific debates and less personal feelings. The Students develop

an appreciation of the fact that the forensic scientist must remain impartial at all times.

55

They are aware that the evidence must be sufficient to prove guilt and that their personal
bias cannot play a role in the solution. This type of mental growth is not developed in

many traditional courses.

DISCUSSIONS AND CONCLUSIONS
COURSE CONTENT
THE BEST AND THE WORST

Overall, I believe that the class has been very beneficial for my students. The
relaxed atmosphere taught them that they can enjoy working at their own pace and the
consequences of procrastination. In addition, they've learned that working as a team means
equal work for all and if one member is ineffective the whole project is jeopardized. They
have learned to deal with the above situation in a responsible and polite manner.

The crime scene role play is probably the most effective part of the unit in terms of
applying what they have learned. This would include their knowledge of preserving and
protecting the scene, performing a thorough search and maintaining a chain of custody. In
addition, they use their knowledge of physical evidence to investigate the evidence they
obtain. lt portrays to them the real life situation of the "unknown", also. The crime solvers
go into the crime scene having absolutely no knowledge of the scenario and must
investigate, analyze and interrogate until they come up with an answer. They must control
their emotions no matter how frustrated they get. Finally they must work together and use
the tools they have obtained in class and their higher level thinking skills to solve the
crime.

The most applicable lab exercises for them are the micrOSCOpe labs, the thin layer

chromatography labs, the spectrophotometry labs and the electrophoresis labs. All of the

56

57

above will be used by the student in college science classes. A strong knowledge of their
use will be beneficial for the student.

Least effective labs, in terms of their vague results, were the lipstick
chromatography and the ouchterlony lab. The students seem to have trouble understanding
the results of the lab and evaluating their uses.

The primary area, in the course, which I would like to see improved include class
length. If the class became a year long course instead of a semester I would be able to
teach many more topics including paint chip analysis, serial number restoration and glass
and soil analysis. I would like to be able to incorporate a unit on the ethics involved with
all of the technological advances, especially DNA fingerprinting.

Overall, I have truly enjoyed teaching this course. Seniors are a very enjoyable
group of students to work with. They have wonderful senses of humor. They also have

the maturity to be dusted with the less formal atmosphere of the course.

DISCUSSIONS AND CONCLUSIONS
COURSE CONTENT
THE STUDENTS

The majority of the students who take this course do so for one of four reasons.
The first (about 20% of the students) is because they have an interest in the law and/or
crime and are interested in learning more about criminal evidence. This student is not
necessarily the top academic student in his/her class. The second reason (about 40% of the
students) is because the student enjoys all forms of science and wants to take any and all
science courses offered. This student usually is academically a good student. The third
reason (about 30% of the students) is because they have had me as a teacher and want to
take another course which I teach. The fourth reason (about 10% of the students) is
because they have heard that the class does not have a book and there are not many tests
and it is their senior year after all . This student is usually a challenge. All students
however come out of the class with an increased level of knowledge and responsibility.

Forensic science topics are usually interesting and intriguing and it is easy to get
most of the students involved in discussions. I try to teach each topic- by bringing in a
crime where the particular type of evidence is used. Students have commented that they
learn material in this course because I "sneak" it in.

Lab activities are a little more difficult to get all students involved in. I have to be
alert all the time to keep all students on task. The relaxed atmosphere of the course

promotes student responsibility. Some students are not ready for this responsibility and

58

59

need extra reinforcement. As the semester progresses, however, they usually progress also.
I am very critical of their lab write-ups initially and many students have to re-do sketches,
questions, and entire labs until they are acceptable by me. They learn quickly to take their
time and do a good job initially and they will be more successful. Lab journals and lab
questions are much more detailed at the end of the semester than at the beginning.

Overall, I see student growth in many areas throughout the semester. The students
learn that it is alright to disagree and debate ideas with their peers. They develop an
understanding of the scientific detail that is required not only in forensics but in research in
general. They learn also that "less structure" means "more responsibility". Many of the
students who take the course are college bound and this experience is a good preparation
for them.

In general, throughout a semester, I see an increase in laboratory skills, thinking
skills and student responsibility. The students learn many of these skills not by lecture but

by promoting their own thinking and therefore understanding.

APPENDICES

APPENDIX A
BACKGROUND LECTURE INFORMATION
Section I : The Crime Scene
Section II: The Microscope
Section III: Chromatography
Section IV: Spectrophotometry
Section V: Electrophoresis
Section VI: Hair and Fiber Evidence
Section VII: Documents and Handwriting Analysis
Section VIII: Fingerprints
Section IX: Drugs
Section X: Toxicology
Section XI: Blood

Section XII: Deoxyribonucleic Acid - DNA

THE CRIME SCENE

In teaching a forensic unit it is not only important to teach the scientific components
of evidence and instrumentation but to include a complete explanation of the crime scene.
"Forensic science begins at the crime scene. If the investigator cannot recognize physical
evidence or cannot properly preserve it for laboratory examination, no amount of
sophisticated laboratory instrumentation or technical expertise can salvage the situation"
(Saferstein 29). Retrieval of evidence from a crime scene, though not necessarily difficult
needs to be done in a systematic and appropriate manner in order to preserve and protect all
of the evidence.

The first ofi‘icer to arrive at the crime scene has three main responsibilities. First the
officer need to provide medical assistance for the injured person(s) and/or arrest the
perpetrator. Secondly, the officer must eliminate any unauthorized individuals from the
scene. Lastly, the officer must barricade and/or guard the area if necessary.

After the initial Preserve and Protect phase of the crime scene is complete the
investigation begins. Investigators will only have a limited amount of time to survey the
crime scene and therefore recording the scene becomes very important. Three general
processes are involved in recording the scene. The first, photography, must take place
before any of the evidence is moved or removed fiom the scene, with the exception of the
injured parties. All physical evidence needs to be photographed. If the size of the object is
significant a ruler may be placed next to it. Videotapes are acceptable. Upon completion

of photography, a rough sketch of the scene needs to be done. Objects need to be shown in

60

61

the sketch by distance from two locations. Distances should be measured not guessed.
North-South direction should be shown on the sketch. A final sketch will then need to be
completed at the laboratory. The third record of the scene is the notes. Notes are taken
throughout crime scene investigations. These are a detailed description of the
investigation. Included in the notes must be a description of the scene, evidence and
disposition of the evidence. "The note taker has to keep in mind that this written record
may be the only source of information for refreshing one's memory months, perhaps years,
after a crime has been processed. The notes must be sufficiently detailed to anticipate this
need" (Saferstein 32). After the initial recording of the crime scene is completed a
systematic search for evidence must begin.

A thorough and systematic search is necessary to ensure that all evidence is located.
Four types of searches could be used and the specific type is determined based on the size
and location of the scene. Items and methods used are determined by the investigators.
For example, a typical murder scene would include a search for a weapon, possible trace
evidence such as hairs, fibers or blood and any other items which might have resulted from
a contact between the victim and the assailant. Failure to perform a thorough search could
result in charges of "cover-up". The investigation can continue beyond the crime scene,
also. Evidence obtained at an autopsy is also important in crime scene investigations.
Autopsy evidence might include fingernail scrapings, blood, hair samples from the body
and recovered bullets. In addition to recovering evidence controls should be obtained also.

Packaging crime scene evidence is also extremely important. Care must be taken to
prevent loss, breakage, spoilage, evaporation or contamination. Every item must be
packaged in it's own container and properly labeled. The investigator must be aware of the

proper container needed for each type of evidence. For example, blood stained material

62

will mold if stored in an airtight container and should be placed in a paper bag. Charred
debris, however, must be stored in an airtight container to prevent evaporation of petroleum
residues. After packaging, the evidence must be submitted to the laboratory and proper
chain of custody must be followed.

Maintaining a chain of custody is extremely important for presentation in court.

Adherence to standard procedures in recording the location of evidence, marking
it for identification and properly completing evidence submission forms for
laboratory analysis are the best guarantee that the evidence will withstand inquiries
of what happened to it from the time of its finding to its presentation in court
(Saferstein 38).

In many cases all individuals involved in handling evidence are asked to testify in court. It
is therefore extremely important that a chain of custody is maintained.

Upon receipt of physical evidence the process of identification must begin. The
expert must follow the identification procedures which have been established for that
particular type of substance. Testing needs to be sufficient to exclude all other possibilities
of identification. Control comparisons need to be complete in an attempt to determine a
common origin.

Evidence can then be divided into two categories, class or individual. Class
evidence is evidence which can be matched to a specific group but not to a type. ABO
blood typing is an example of this. A blood specimen which types out as "AB" could
belong to 43% of the population (Saferstein 324). This is sufficient to exclude the other
57% of the population but it does not pinpoint one individual. Individual evidence is that
evidence which can be matched directly to a source. Fingerprints belong to this category

of evidence. "The French scientist Victor Balthazard has mathematically determined that

63

the probability of two individuals having the same fingerprints is one out of I x 10 6O "

(Saferstein 365). Therefore, Forensic Science considers fingerprints individual evidence.
Both types of evidence are important in the solution of crimes. Class evidence, however

needs to be used in conjunction with eye witness accounts and other evidence.

THE MICROSCOPE

The microscope is probably the most valuable tool for the forensic scientist. As
shown in the Lindbergh case the microscope can be the main instrument used in an
investigation. From the simplest microscope, the magnifying glass, to the powerful
scanning electron microscope the usefulness is extraordinary. The compound microscope
is one that is commonly found in high school laboratories with magnifications ranging
from 40X to 450x. The stereomicroscope is also commonly used in high schools. This
instrument gives a three dimensional image with lower magnification. The comparison
microscope can be found in forensic laboratories and is extremely useful in comparing two
pieces of evidence or a piece of evidence and a control. This microscope basically is two
separate compound microsc0pes which are connected by an optical bar and has one
binocular eyepiece. The experimenter is able to view both stages at the same time in an
attempt to compare and possibly match evidence. The fourth type of microscope used in
forensics is the polarizing microscope. Glass and soil are two substances commonly
analyzed with this microsc0pe. The fifth type, only used in advanced laboratOries, is the
Scanning Electron Microscope. Instead of using light as an imaging source the microscope

utilizes electron emission. The SEM image has a high magnification and resolution.

64

CHROMATOGRAPHY

The second important type of forensic analysis is chromatography. There are
several types of chromatography. The basis behind all types however is the same. "The
theory of chromatography has as its basis the observation that chemical substances have a
tendency to partially escape into the surrounding environment when dissolved in a liquid or
when absorbed on a solid surface" (Saferstein 106). In general, chromatography is said to
have a stationary phase and a moving phase. Sample components which have a chemical
preference for the stationary phase will not travel as far on a chromatogram as those that
prefer the moving phase. The two types of chromatography used in the high school
classroom are paper chromatography and thin layer chromatography. Paper
chromatography utilizes paper as its stationary phase (Modern Chemistry Laboratory
Experiments 43) and usually water as one choice of solvent. In thin layer chromatography
a glass plate usually is coated with silica gel or aluminum oxide as its stationary phase. A
solvent (moving phase) is drawn through this granular phase by means of capillary action.
"Those components with the greatest affinity for the moving phase will travel up the plate
at a faster speed as compared to those that have greater affinity for the stationary phase"
(Saferstein 113). Upon completion of the chromatography the plate is visualized. This
sometimes requires the use of ultraviolet light. An Rf measurement is then taken of all of
the bands. More advanced types of chromatography are used in forensic laboratories.
These include Gas Chromatography (GC) and High Performance Liquid Chromatography

(HPLC). Gas chromatography uses gas as its moving phase. This gas flows over a thin

66

film of liquid which is the stationary phase. In HPLC the "moving phase is a liquid which
is pumped under pressure through a column filled with fine solid particles" (Saferstein

l 12). This process is different from GC in that it can be performed at room temperature.
Therefore, heat sensitive substances can be analyzed without destruction. Organic
explosives and some types of drugs are commonly analyzed using HPLC. The major

drawback with chromatography techniques is that the analysis is not conclusive.

SPECTROPHOTOMETRY

Spectrophotometry is another form of analysis used in evidence identification. This
technique utilizes the absorption of light by a substance as its basis. Substances can be
categorized by the light they absorb. The spectrophotometer measures this absorption. As
light is passed through the sample, the spectrophotometer detects and records the overall
light absorption by the substance at a given wavelength. The typical spectrophotometer
used in a high school utilizes an ordinary tungsten light bulb as its light source. More
advanced laboratories use ultraviolet, infrared or mass spectrophotometers. Ultraviolet
spectrophotometers measure the absorbance of ultraviolet light. Infrared spectroscopy
measures infiared absorption and is much more SOphisticated than ultraviolet due to the
complexity of infrared light. The infiared spectrum of a substance is considered a
"fingerprint" of that substance. The mass spectrophotometer is used in conjunction with
the GC as a means of producing a specific identification. The mass spectrophotometer
fragments and then masses the components of the sample which emerge from the GC. No

two substances have the same fragmentation pattern.

67

ELECTROPHORESIS

Electrophoresis is another useful procedure used in evidence identification. This
process is similar to thin layer chromatography except that electricity is used to separate the
substance components. The stationary phase is usually a gel like substance which has
wells in it. The samples are placed in the wells and an electric current applied to the gel.
Components with an electric charge will migrate in the gel. This procedure is used

extensively with blood and blood component identification.

68

HAIR AND FIBER EVIDENCE

Hair and fibers are Often left at crime scenes. "Every time we enter a room, we
deposit a bit of ourselves. When we leave, we take something with us" (Nichols 22).
This causes even the most perfect crime to have flaws. Hair and textile fibers are left by
even the best criminal. Both types of evidence fall into the category of class evidence. It is
possible to determine a group of individuals to whom the evidence might belong to but
rarely one specific item or individual. An exception to this might be a large piece of fabric
which was torn out of a piece of clothing and which can be matched back to that item.
There are many characteristics of both that make them useful in criminal investigations.

Hair is a protein substance which grows out of an organ known as a hair follicle.
"The average, normal human body has approximately 250,000 hairs. These hairs are
normally shed at the rate of 250 per 24-hour period" (Miller and Brown 83). There are
three major parts to the shaft of the hair, the cuticle, cortex and medulla. The cuticle is the
outermost or external part of the hair. It is composed of a series of overlapping scales. The
microscopic appearance of these hairs is called a scale pattern. Scale patterns are very
useful in determining the species of animal that the hair is from. See Figure 1. Inside the
cuticle is a region called the cortex. The cortex contains the pigment granules of the hair
shaft. These granules and their distribution are useful in determining the racial origin of a
human hair. The central portion of the hair shaft is known as the medulla. There are four
general categories of medullas: they are fragmented, interrupted, continuous or stacked.

The type of medulla present in a hair Shaft helps to determine the species of animal which

69

70

the hair belonged to. See Figure 2. Other characteristics of the hair which are useful in
identification include color, length, diameter, cross section (See Figure 3), root patterns
(See Figure 4) and medullary index. The medullary index is the ratio of the medulla

diameter to the shaft diameter.

 

 

 

 

 

 

 

 

a”.

rear

H

‘

‘30!

“’12
I... ._ .._ *}— rncuemanv mus-am
— _ - 4 INTEHIU'TEO "‘UH‘N'
r fi

CONTI’OUOU‘ {MUHA'II

a ma... ..... ..

 

M..‘..“i"“'l"__ sucxto IANIMAL)

 

Figure 1: Scale patterns. Figure 2: Medullas

Miller, LS. and A.M. Brown. (I 990). Criminal Exidenne Labnmtntx Manual All

Intrndnclinn In the Crime Lnbnmtntx Emmi Editinn. Ohio. Anderson
Publishing Company.

71

®®C€~D

O'LONG C!CAI-;uugo “ENIICDu

®®©

nouno OVAL (YE-SNA'FD

/" fl,— )
/ ’
'—'_""‘ "I ’ Slug—snap“) RCO? INUMANI
-_—____-—_—___..——-—-""—'—"' .

" ”NI-Suns: Root iAmuau

 

Figure 3: Cross sections Figure: Root patterns

Miller, LS. and A.M. Brown. (1990). Criminal Exideace Laboratory Manual An

Introduction to the Crime Lahomtotx Second Edition. Ohio. Anderson
Publishing Company.

72

Textile fibers, like hair (sometimes they are hair), are commonly found at crime
scenes. Fibers can be divided into two categories, natural and man-made. "There are three
basic natural fibers from which clothing and material are made: (1) silk, (2) wool, and (3)
cotton" (Miller and Brown 169). There are two types of man-made fibers, regenerated and
synthetic. Regenerated fibers are which are produced from the cellulose components of
natural raw materials. Examples include rayon and acetate. Synthetic fibers are those
which are manufactured totally from synthetic materials. Examples are nylon and
polyester. Fiber characteristics which are useful in identification include microscopic
appearance (color, diameter and cross section), effect on litmus, residue and odor from

burning, birefiingence and solubility.

DOCUMENTS AND HANDWRITING ANALYSIS

Documents and handwriting are another type of evidence sometimes left at crime
scenes. Questioned documents can be either class or individual evidence depending on the
situation. Any document with handwritten or typed markings on it and whose authenticity
is in doubt are considered questioned documents. Many items fall under this broad
definition. Letters, checks, lottery tickets and wills are examples. Other items which might
be considered "questioned documents" are walls, windows and doors. Analysis of
documents includes detennining chemical make-up such as fiber content and ink analysis.
In addition attempts to alter a document must be recognized by the document examiner.
Handwriting comparisons are another type of analysis the document examiner performs.
Unconscious writing can never be duplicated between two individuals. Characteristics
which make handwriting samples different include line quality (the skill of writing),
spacing of words and letters, letter size, penlifts and separations, connecting strokes,
beginning and ending strokes, unusual letter formations, shading, slant, baseline habits,
embellishments and placement of diacritics (Miller and Brown 201). Comparisons must
include both those characteristics which are the same between two writing samples and an
explanation of any characteristics which are different. A suflicient number of comparisons
must be made between a known and questioned document to exclude the possibility that
the document originated from any other source. Therefore handwriting is considered an

individual type of evidence.

73

FINGERPRINTS

Fingerprint evidence is especially interesting to discuss in the high school
classroom because of the widespread use in crime related television shows and movies. "In
the United States, the first systematic and official use of fingerprints for personal
identification was adopted by the New York City Civil Service Commission in 1901"
(Saferstein 365). Fingerprint evidence is now widely used and accepted as individual
evidence.

There are three fundamental principles of fingerprinting. The first states that a
fingerprint is individual evidence. In a 90 year period no two fingerprints have been found
to be identical. The second principle states that a fingerprint will not change during an
individuals lifetime. Attempts at scarring the skin to obliterate a print have been shown to
be unsuccessful. The third principle states that fingerprints result from skin ridges on the
surface of the palms of the hands and soles of the feet. On these ridges are pores. Sweat
and oils are released from the skin through these pores. Whenever an individual touches
an object traces of these oils are left behind as a "latent" fingerprint . These prints can then
be dusted with a fine powder, lifted with clear tape and deposited onto a contrasting
material. Once successfully lifted a classification can begin.

Classification of a print requires analysis of the ridge characteristics of the print.
Three general categories of fingerprint types exist: loops, whorls and arches. Loops are the
most common type of print. "A loop must have one or more ridges entering from one side

of the print; recurving, and exiting from the same side" (Saferstein 369). See Figure 5.

74

75

There are two types of loops, an ulnar loop and a radial loop. Ulnar IOOps open towards
the little finger while radial loops open towards the thumb. The second type of fingerprint
is the whorl. There are four categories of whorls; plain, central pocket, double loop and
accidental. Plain and central pocket whorls each contain one ridge which makes a
complete circuit. "If an imaginary line is drawn between the two deltas (See Figure 7)
contained within these two patterns, and if the line touches any one of the spiral ridges, the
pattern is a plain whorl. If no such ridge is touched, the pattern is a central pocket loop"
(Saferstein 371). A double loop is simply "two loops combined into one fingerprint" and
an accidental whorl "either contains two or more patterns (not including the plain arch) or
is a pattern not covered by other categories" (Saferstein 371). The last type, arches, are
characterized by ridges entering one side of the print and exiting the other. Two categories
of arches exist. Plain arches rise smoothly in the center while tented arches have a distinct
spike in the center (Saferstein 371). See Figure 5. "Sixty to 65 percent of the population

has loops, 30 to 35 percent has whorls and about 5 percent has arches" (Saferstein 369).

76

                  

\0 ' ‘
rum ARCH reurzo “cu ULNAR L00?

 

DOUBLE LOOP LATERAL POCKET LOOP

 

Figure 5: Fingerprint types.

Miller, LS. and A.M. Brown. (1990). Criminal Evidence Laboratonr Manual An

Introduction to the Crime Laboratorx Second Edition. Ohio. Anderson
Publishing Company.

77

After initial determination of a print type a more detailed analysis can begin. There
are several points of comparison which can be made between two prints. Included in these
points are "ridge endings, bifurcations, islands, dots, bridges, spurs, enclosures, double

bifurcations, deltas and bifurcations" (Miller and Brown 31).

Criminal courts will accept a minimum of twelve identical "characters" or
"points" as a positive match in latent print identification and comparison with
known inked prints. When twelve identical characters are located and properly
marked, the identity of the suspect cannot be refuted (Miller and Brown 31).

Besides comparison of individual points a classification of a complete set often prints has
been established. '

The first fingerprint classification system, known as the Henry system, was
developed in 1901 by Scotland Yard. This system, however, has been replaced in the
United States by the FBI system because of the need for an expanded system. This new
system is used to determine the primary classification of a set of prints. The presence of a
whorl on a given finger is the determination of the numerical value for that finger. Once
this value is determined it is placed in the fiactions below.

R. Thumb R. Middle R. Little L. Index L. Ring
A whorl in fraction 1 gets a value of 16; fraction 2, a yalue of 8; fraction 3, a value of 4;
fraction 4, a value of 2; and fraction 5, a value of I. All individuals then add 1/1 to their

ratio. If a whorl is not present on a given print then that finger gets a value of 0.

78

For example, Sue O. has whorls present on her left thumb, right thumb and right middle.
Her classification would look like this:

(I
l

+0+4+Q+0+l 5
+8+0+0+0+

6 25

To use this system a complete set of prints needs to be obtained and rarely are all 10 prints
left at a crime scene. Another system has been developed to deal with this problem.
Automated Fingerprint Identification Systems (AFIS) are computer scanning
devises which "digitally encode fingerprints so that they can be subject to high speed
computer processing" (Saferstein 373). This system has allowed an integration of
fingerprints across the nation. Individuals who are arrested for a crime are fingerprinted
and these prints are entered into the AFIS system. If this individual has left prints at a
crime scene somewhere else in the United States the system will indicate this. The major
advantage of the system is the time it saves investigators. Much less time is being spent
developing suspect lists and more time spent investigating suspects generated by the AFIS

computer system.

DRUGS

Drugs and their analysis play a large part in many criminal investigations. "In the
United States, the epidemic proportions of illegal drug use has produced a situation that
finds more than 75 percent of the evidence being evaluated in crime laboratories to be drug
related" (Saferstein 216-217). Drugs fall into two major categories, illegal and legal.
There are four categories of commonly abused drugs; depressants, stimulants, narcotics
and hallucinogens. Narcotics are those drugs which relieve pain by acting on the Central
Nervous System. Examples of narcotics are morphine and heroine. Depressants, in
general, slow down and impair normal body functions. Alcohol and barbiturates are both
depressants. Stimulants are drugs which produce a feeling of alertness followed by a
decrease in fatigue and appetite. Cocaine and amphetamines are both stimulants.
Hallucinogens are drugs that cause changes in normal thought processes. Examples of
hallucinogens are marijuana and LSD. In order to have uniform drug laws throughout the
United States, the federal government has established the Uniform Controlled Substances
Act. "The federal law establishes five schedules of classification for controlled substances
on the basis of a drug's potential for abuse, potential for physical and psychological
dependence, and medical value" (Saferstein 234) . Schedule I drugs have a high potential
for abuse and have no currently accepted medical use. Included in this schedule are heroin
and marijuana. A schedule 11 drug is one which has a high potential for abuse but does
have a current medical use. Schedule II drugs include PCP and amphetamines. Schedule

III drugs have a lower potential for abuse and have a currently accepted medical use.

79

80

Codeine falls into this category. Schedule IV drugs have a low potential for abuse and
have a current medical use. Darvon and Valium are both schedule IV drugs. Schedule V
drugs have low potential for abuse. The criminal penalties for sale and possession of drugs
is related to their placement in the schedule. The lower the schedule the higher the penalty.
Several types of testing exist for identifying drugs but because of the evidence few can be

used in a high school laboratory.

TOXICOLOGY

Forensic toxicology is another type of investigation that is closely related to drug
analysis. Toxicology involves the detection of drugs and poisons in blood or body fluids,
tissues or organs. Alcohol is a major category of drug that the toxicologist looks for. The
toxicologist, however, is also responsible for identification of other drugs and poisons.
Once identification of the drug is complete the toxicologist may then be called upon to

assess its influence on the behavior of the individual involved.

81

BLOOD

Blood samples have other applications at the crime scene also. Upon obtaining a
blood stain a forensic serologist must determine whether or not the source of the blood is
human. If so, an initial blood typing will be done. Common tests include A-B-O typing
and Rh factor typing. The basis for both tests is that a red blood cell contains on its surface
a protein structure called an antigen. An individual with type A blood has "A" antigens on
the surface of their red blood cells, individuals with type B blood have "B" antigens on
their red blood cell surface, and individuals with type 0 blood have neither antigen on the
surface of their red blood cells. For every antigen there is a specific antibody. If the
antibody for B type blood is given to an individual with type B blood agglutination will
occur. This massive clumping of red blood cells in the human body could cause death due
to the inability of the red blood cell to do its primary job of transporting oxygen and carbon
dioxide. The procedure of typing blood is simply a process of placing the unknown blood
sample into samples of known antibodies and watching for agglutination. Rh typing
follows the same principle. An Rh positive person has the Rh antigen while the Rh
negative person does not. The entire process of blood typing is used as class evidence and
is most usefirl in eliminating suspects. A typical distribution of blood types in the United

States is 43% type 0, 42% type A, 12% type B and 3% type AB.

82

DEOXYRIBONUCLEIC ACID - DNA

Deoxyribonucleic acid (DNA) is the name given to the genetic material found in
most cells of living organisms. The coding of certain parts of DNA is unique to every
individual. These unique parts can be used to verify to whom a sample of blood or body
fluid belongs. "Sample evidence taken from a crime scene when matched with a suspect's
DNA fingerprints, can be used to prove innocence or guilt" (Science Kit and Boreal
Laboratories 1). Human genes are the subunits of DNA. The nucleotide base sequence
related to a certain gene determines the characteristics that an individual will have. This
gene coding is similar between all humans. Between these codes for genes, however, are
the random codes that have become important to forensic scientists. "Not all the letter
sequences in DNA code for the production of proteins. Portions of the DNA molecule
contain sequences of letters that are repeated several times" (Saferstein 353). It is these
repeating strands, called restriction fragment length polymorphisms (RFLP'S) that are used
to distinguish one individual from another.

The process of DNA typing follows the following sequence. The DNA is isolated
fiom the blood or body fluid sample. Restriction enzymes are added to the sample. These
enzymes are specific for known or target codes of DNA. The restriction enzymes cut the
RFLP's out of the DNA sample. The RFLP's are then placed into a gel electrophoresis
apparatus. An electric current is applied to the gel. Since DNA is a negatively charged
molecule it will migrate towards the positive pole. The smaller DNA fragments will

migrate further in the gel than the larger fragments. I like to use this analogy with my

83

84

students. Imagine a bowl of jello with cut up peaches in it. Some of the pieces are very
large and some are very tiny. Imagine then that you put a straw into the jello and try to
suck the cut up peaches up to the straw. The smaller pieces will be easier to pull through
the jello than the larger pieces. When electrophoresis is complete a radioactive probe with
a complementary base sequence is attached to the DNA sample. The DNA can now be
seen using X-rays. This "fingerprint" can be used to compare a suspects DNA to DNA
found at a crime scene. Many cases have been solved using DNA fingerprinting. In
addition people have been released from prison because DNA fingerprinting showed them

to be innocent.

APPENDIX B
LABORATORY ACTIVITIES

Section 1: Paper Chromatography
Section 11: Practice in the Use of the Microscope
Section III: Examination of Hair by Light Microscopy
Section IV: Analysis of Fibers
Section V: Carpet Sample Lab
Section VI: Determination of Lipstick Dyes Using TLC
Section VII: The Analysis of Questioned Documents

Section VIII: Analysis of Inks By Thin Layer
Chromatography

Section IX: Visualization and Examination of Fingerprints
Section X: Shoeprints

Section XI: Urine Analysis Using Paper Chromatography
Section XII: Ouchterlony Diffusion

Section XIII: Determination of the Peak Absorbance of a
Substance Using Visible Spectrophotometry

Section XIV: Identification of Salicylates In Blood By
Spectroscopy

Section XV: The Alcohol Breathalyzer Test: A Laboratory
Simulation

Section XVI: Agarose Gel Electrophoresis

Section XVII: DNA Electrophoresis

PAPER CHROMATOGRAPHY

Paper chromatography is a method of separating mixtures by using a piece of absorbent
paper. In this process, the solution to be separated is placed on a piece of dry filter paper.
This is the stationary phase. A solvent (the moving phase) is allowed to travel across the
paper by capillary action. As the solvent front moves, the components of the mixture
separate. The components of the mixture that are most soluble in the solvent and least
attracted to the paper travel the farthest.

In this experiment you will place a small spot of black, water soluble ink near the center of
a piece of filter paper. By means of a wick, water will be drawn to the center of the filter
paper and will then spread outward towards its edge. The colored molecules that make up
the black ink mixture will be distributed by the solvent along a path to the edge of the
paper. Because each different brand of black ink is a unique mixture of colored molecules,
each pattern on the paper or chromatogram is characteristic of the brand of pen used.

Chromatography is an important tool of the forensic chemist in solving crimes. This
method can help identify the brand of pen used to write a ransom note. Using
chromatography, ink manufacturers can quickly determine if a competitor has stolen their
"secret" formula.

OBJECTTVES: At the completion of this laboratory exercise the student will be able to:

1. Perform the technique of paper chromatography.
2. Separate the colors of different inks.
3. Identify an unknown ink using paper chromatography.

CRIME SCENE:

Upon arrival to school today, Mrs. Pawloski found a threatening note attached to her
door,... "Chemistry 11 students, BEWARE, your lives are in danger. You will be sony for
treating me so poorly." After careful evaluation Mrs. Pawloski narrowed her list of
suspects to six. She then confiscated their black ink pens. Your job is to analyze the inks
by paper chromatography and determine who the culprit is.

85

86

MATERIALS:

filter paper, 12 cm

six numbered, water soluble, black ink pens
filter paper wick

petri dish

filter paper with four spots of unknown black ink
sample of ink from threatening note

PROCEDURE 1: Paper chromatography

1. Use a pencil to sketch a circle about the Size of a quarter in the center of the piece of
filter paper. See Figure l.

2. On the circle make a dot with pen #1 and write a number 1 next to it with a pencil.
Using black pen # 2 make a dot and place a number 2 next to it with a pencil. Repeat

with all pens.

 

Figure l

3. Use a pencil to poke a small hole in the center of the filter paper. Insert a piece of filter
paper wick through the hole.

4. Fill the petri dish bottom halfway with water. Set the wick of filter paper into the water.
"Do not allow your black dot prepared paper to become submerged in the water.”

See Figure 2.
/ fa -\ \ (Filter Paper
I ‘ Perl—h. dish

wickfi

 

‘- wocl‘er‘

87

5. When the water is 1 cm from the outside edge of the paper, remove the paper from the
petri dish and allow the chromatogram to dry. Record the colors that have separated
from each of the six different black inks in the data table. You may want to use colored
pencils to record this information.

6. Ask Mrs. Pawloski for a piece of filter paper with four black dots of unknown ink.
Repeat steps 3 through 5.

7. Use your known information to identify your unknown inks. Record this information in
your data table.

88

PROCEDURE II: Identification of the pen used to write the note.
1. Prepare a procedure for identifying the pen which was used to write the scandalous note.
2. Perform the procedure and detemrine which pen was used.
3. If the procedure was successful, write it up, step by step, on page 4 of this lab sheet.
If the procedure didn't work, prepare a different one and perform it. Continue this until
you get a procedure which works. Write up the correct procedure on page 4 of this

lab sheet.

4. Record your pen identification conclusion in the conclusion section of the lab sheet.

DATA:
KNOWN PEN INKS
pen number dot number record of chromatogram
center middle edge
1 l
2 2
3 3
4 4
5 5
6 6
UNKNOWN INKS
pen number dot number record of chromatogram
center middle edge
7 7
8 8
9 9
10 IO
INK FROM TI-IREATENING NOTE
Record of chromatogram

center middle edge

89

CONCLUSION:
1. Which known pen made the dot of the following unknown inks?
7 -
8 _
9 -
IO-

 

 

 

 

2. a. Who did you conclude wrote the threatening note?

b. Why did you conclude this? Be specific.

QUESTIONS:

1. What procedure did you use to identify the ink from the note?

2. Some components of ink are minimally attracted to the stationary phase and are very
soluble in the solvent. Where are these located on the filter paper during chromatography?

3. What can be said about the properties of a component ink that travels only half the
distance to the final. solvent front?

4. Predict the results of forgetting to remove the chromatogram from the water in the petri
dish until the next day.

90

REFERENCES:
Tzirnpoulos, Nicholas D., H.C. Metcalfe, J. Williams, Joseph Castka. (1990). Modem
Chemistry Lahoratorx Expon'ments. Teacher Edition. Texas. Holt, Rinehart, and Winston

Inc.

Revised by Karen Pawloski

PRACTICE IN THE USE OF THE MICROSCOPE

The microscope is one of the most valuable tools of the forensic scientist. She uses it to
study hair, fibers, seeds, soils, metals, paints - anything and everything involved in a crime.
It is believed that engravers used glass globes filled with water as magnifying glasses at
least 3000 years ago. The simplest microscope is called a magnifying glass. Optical
microscopes magnify because light rays reflected from an object bend (refract) as they pass
through one or more lenses.

How big you can make the object depends on the refractive index (bending power) of the
glass in the lens. Hand lenses are 3 to 10X. Since the light rays are spread out when an
object is magnified, the magnified object is not as bright as the original. To make it as
bright as it was originally, additional light must be used.

Suppose that you took a small section of a magnified object and placed a second lens over
it. This magnified section could then be firrther magnified and we would have a compound
microscope. The Dutch Spectacle maker, Zacharias Janssen, is credited with discovering
this principle and making the first compound microscope in 1590. Since then, there have
been many improvements, although the basic concept has remained essentially unchanged.
Magnification up to 400X is possible with ordinary illumination. With a substage
condenser to focus more light on the object and with better lenses, it is possible to go to
lOOOX magnification. About the highest magnification that can be Obtained with a
compound microscope is 2500X.

The quality of a microscope resides in the lenses. Slight imperfections can cause large
distortions in the object that is viewed. In addition, the various colors refi'act at different
angles, so correcting lenses must be added. Expensive microscopes have excellent
correcting lenses, while less expensive microscopes may not even have correcting lenses.

In working with a compound microscope, you will find the following terms useful.

Working distance - the distance between the specimen and the tip of the objective
lens. In general, the higher the magnification, the shorter
the working distance.

Depth of focus - the thickness of the object that is simultaneously in focus. The
higher the power of magnification, the less is the depth of
focus.

Field of view - the area or diameter of the specimen that is in view. The higher
the power of magnification, the less is the field of view.

91

The general structure of the compound microscope is shown in Figure l.

 

 

 

 

 

Figure l: The Microscope

Clifton Meloan, Richard James, Richard Saferstein. (1990). Criminalistics: An Introduction
to Eomsie Science Lab Manual. New Jersey. Prentice Hall.

MATERIALS:
microscope, compound microscope, stereoscopic
medicine dropper lens paper
scissors cover slip
microsc0pe slides newspaper
tea paper match books

unknown ink sample unknown paper match sample

93

PROCEDURE:
PART A:

1. Obtain a compound microscope from the cabinet, and cany it back to you
lab table.

2. With a piece of lens paper, lightly wipe any dust and grease from all exposed
glass surfaces. Never use anything else to do this job.

3. Spend the next few minutes becoming familiar with the names and locations of
the various important parts of the instrument.

Several important rules are to be noted in connection with the foregoing procedures:

a. To find an object, always start your examination with the low power objective,
never with the high. The low power reveals an area on the slide some 20
times greater than the high-power, making it 20 times easier to locate the
desired object.

b. To bring the object into focus, always focus upward, with the coarse adjustment.
(NOTE: Some microscopes focus by moving the stage up and down rather
than the body tube. In such cases the focusing is downward- away from
the moveable parts.) You want to focus upward because when your eye is
at the ocular (eyepiece), it is impossible to determine how far down or up
the tip of the objective has traveled. In focusing down, carelessness may
result in crushing the specimens.

c. When the high power objective is being used, never use the coarse adjustment.

4. Cut the letter "h" fi'om a newspaper. Place it on a clean slide, and with a medicine
dropper, place 1 drop of water on the letter.

5. Wait a moment before covering it with a cover slide.

6. Place the slide on the stage and clamp it down. Move the slide so that the letter is in the
middle of the hole in the stage. Make certain that the low-power objective is in
place. Viewing the stage from the side, use the coarse adjustment wheel to lower
the objective until either the stop is reached or the objective is approximately
2 cm from the cover slip.

94

7. Turn on the substage illuminator on the microscope.

8. Now, looking through the ocular, slowly raise the tube with the coarse adjustment
knob until the letter "h" is in focus. If you cannot see the object, center the
slide more carefully and repeat the whole procedure. The focus may be made
sharper by a slight turn on the fine adjustment knob.

9. Open and close the iris diaphragm by turning the diaphrarn handle, which projects
laterally from the lower portion of the condenser. The iris diaphragm controls
the amount of light reaching the specimen. Adjust it to make the image as sharp
as possible.

10. The image is in focus 3 to 4 mm above the eyepiece. Thus, there is no reason to press
one's eye to the ocular.

l 1. To change to the high power, make sure that you have focused sharply under low
power on the object and centered it in the field. Then carefully swing the high
power objective into place. The high power objective should not strike the slide,
though it will come very close. A few turns of the fine adj ustrnent knob, either
up or down, should suffice to bring the "h" into sharp focus.

12. Draw the "h" shown on high power in your lab notebook. Don't forget to carefully
label your drawing.

PART B: THE STEREOSCOPIC MICROSCOPE:

1. Using the stereoscopic microscope at the front lab station, familiarize yourself with the
parts of the microscope.

2. Place the previously prepared "h" slide onto the microscope stage.

3. Set the magnification knob to the highest power (2X or 3X). Look through the right
eyepiece and adjust the focusing knob until the letter "h" is sharp.

4. Draw the "h" seen using the stereoscopic microscope in your lab notebook.
5. Using the steps outlined above, examine tea using the Stereoscopic microscope.

6. Draw the tea seen using the stereOSCOpic microscope in your lab notebook.

95

7. Examine the tips of your fingers under the stereomicroscope. Locate the ridges that
form a fingerprint. Locate the sweat pores that exist on these ridges.

8. Draw a stereosc0pic image of your fingerprint in your lab notebook.
PART C: COMPARISON OF PAPER MATCHES

From time to time a forensic laboratory may be asked to see whether a tom-out paper
match comes from a partially used book, usually taken from an accused person.

Cursory examination of any matchbook will reveal that it contains two pieces of cardboard
secured in the book with a staple. The individual match body is formed by a series of
partial cuts in this cardboard; thus each layer of matches was originally a single piece of
cardboard.

The obvious first attempt to match a tom-out match to a partially filled match book requires
physically fitting the torn edges of the match to the corresponding portion of the torn book.
Barring success in this attempt, a forensic examiner will then try to compare the suspect
match with matches remaining in the book in order to establish an adjacent relationship.

Such comparison can be conducted under a stereoscopic microscope. The most significant
features to look for in the comparison of paper matches are:

1. Color, width and thickness.

2. Most matches are made from reprocessed cardboard. Examination of the match
edges reveal inclusions consisting of a large variety of colored fibrous
material, aluminum foil, and other contaminants that were involved in the
production of the cardboard. A side-by-side examination of matches
for comparable inclusions is probably the easiest and most significant
feature to look for in match comparisons.

3. Another feature for comparison is the presence of continuous fibers between
adjacent matches. These fibers may exist on upper and lower surfaces
of the matches.

96

CRIME SCENE "A"

A burglary has been committed, and, apparently, in addition to the burglars inside the
building, a lookout was posted. The detective at the scene noticed a few cigarette butts by
the back door, as well as a few paper matches. He picked these up as possible evidence. a
few days later three suspects were apprehended. A search of the clothing in their
apartments yields several books of matches in their pockets. Your job is to see if the match
found at the back door is from any of the books recovered.

Method
1. You will be given one match from the crime scene and the matchbooks.
2. Compare the matches and books for color, width and thickness similarities.

3. Under the highest power of the stereoscopic microscope, hold the edges of the matches
side by side and compare them for any matching characteristics.

4. Determine whether your match could have originated from any of the matchbooks.

CRIME SCENE "B"

A student at a prominent University in Michigan is suspected of cheating on his Chemistry
final exam. The situation actually occurred when the student was returned the graded
exam. The professor who corrected the exam said that the student did not give an answer
for problem #17 and the professor drew a red "X" through the box where the answer
should have been. However upon reviewing the returned test the student said that there
was an answer in the box and it was correct. The answer was written in pencil. Your job is
to determine, using the stereoscopic microscope which was written first, the red ink pen or
the pencil.

DATA:

Make sketches of everything you've looked at using the microscopes in your notebook.
Make sure everything is properly labeled.

97

QUESTIONS:

1. When you examined the "h" under the low power objective of the compound
microscope was the image right side up?

2. What is the total magnification at high power of your compound microscope?

3. When you examined the "h" using the stereoscopic microscope was the image right
side up?

4. What was your conclusion for Crime Scene "A"? Explain your answer. Use diagrams
and sketches.

5. What was your conclusion for Crime Scene "B"? Explain your answer. Use diagrams
and sketches.

REFERENCES:
Clifton Meloan, Richard James, Richard Saferstein. (1990). Criminalisties: An Introdnotion
to Forensic Science Lab Manual. New Jersey. Prentice Hall.

Revised by Karen Pawloski

EXAMINATION OF HAIR BY LIGHT MICROSCOPY

The analysis of single hairs is fairly straightforward, involving almost exclusively a
microscopic morphological examination of the internal structure of the hair. The analysis
of a suspect hair fiom a crime scene involves the determination of whether or not the object
is a hair or a fiber, what species of animal it belongs to if it is a hair and finally, what
degree of association can be made between the crime scene hair and hairs from a known
source.

Although it is not possible to individualize a single hair (or even a whole group of hairs) to
a particular person (or animal), it is possible to associate the unknown hair to an individual
to a very high degree. This is accomplished by a careful morphological examination which
will determine a number of physical characteristics. In comparing known and unknown
hairs, the similarity of these characteristics will determine the degree of association of the
hairs.

In this lab you will examine animal (non—human) and human hairs to determine how one
species can be differentiated from another. You will then be given hairs taken from a
crime scene and asked to evaluate them.

MATERIALS:

compound microscope microscope slides
coverslips human hair

horse hair dog hair

cat hair glycerin
isopropyl alcohol clear nail polish
rubber cement Polaroid fixative
PROCEDURE:

PART A: Visual Examination of Hair
1. Look at the hair. Document the color and length of the hair.
2. Feel the hair. Determine and document its coarseness.

3. Document the shape of the hair strand. For example, is it straight or is it curly?

98

99

PART B: Microscopic Examination of Hair

1. Obtain a strand of human head hair. This can be taken from your head or your partners
head.

2. Place the hair on a microscope slide.

3. Place a drop or two of glycerin on the hair and place a coverslip on top of it. This is
called a wet mount.

4. Place the slide on the stage of the compound microscope and adjust the magnification
to lOOX.

5. Locate the root end of the hair, if it has one. If the hair has been forcibly pulled out you
will see a bulb shaped enlargement.

6. Make a Sketch of what you see in your lab notebook.

7. Scan the length of the hair. Observe the medulla. If one is present, determine the type.
Draw a sketch of the hair shaft in your notebook.

8. Examine the tip of the hair. If the hair has been cut recently you will to a square
appearance to the end. If the hair has Split ends, this is normally due to waving,
bleaching or repeated brushing.

9. Evaluate the medullary index of the hair.

10. Repeat steps 1 - 8 for dog, cat and horse hair. Make carefirl observations to determine
any microscopic differences between the four types of hair you have observed.

PART C: Scale Patterns.
Scale patterns are of little value in human hair comparisons but can aid in
distinguishing animal hairs. You will now examine scale patterns of dog, cat, horse and

human hair.

1. Clean a strand of human hair by pulling it through a fold of tissue moistened with
alcohol to remove grease and oil from the hair surface.

2. Smear Polaroid fixative on a clean microscope Slide.

100

3. Irnbed hair into the fixative.

4. Let dry 5 - 10 minutes.

5. Remove hair from fixative.

6. Examine the scale patterns using the compound microscope.
7. Sketch what you see in your notebook.

8. Using a hair from the same source repeat steps I - 7 using rubber cement as your
mounting medium. '

9. Using a hair from the same source repeat steps 1 - 7 using nail polish as your mounting
medium.

10. Repeat steps I - 9 for horse, cat and dog scale patterns.
PART D: Hair cross sections.

1. Obtain 2 or 3 human head hairs.

2. Thread them 2 - 3 em up the tip of a Pasteur pipet.

3. Pour one or two drops of Norlands 65 into the pipet from the top and allow to run into
the tip.

4. When the tip is full cure the Norlands under long wave UV light for 15 minutes.

5. With a single edge razor blade, chip away the glass of the tip and cut a thin section of
the Norlands and hairs.

6. Mount it in a drop of 1.53 Cargille Refiactive Index oil with a coverslip.
7. Observe under the microsc0pe.
8. Sketch what you see in your notebook.

9. Repeat steps 1 - 8 for horse, cat and dog hair.

10]

PART B: Crime scene

A women is found murdered in her apartment. Upon examination of her clothing the
detectives find several strands of hair. The woman has long blond hair but the strands all
range between 3 and 6 cm in length and are black in color. The woman has two dogs and
three cats. You will be given the hair samples which were retrieved from the clothing.
Determine the species origin of the hair samples.

FOLLOW-UP:

1. Prepare a table comparing the morphological characteristics of human, dog, cat and
horse hair.

2. Explain why hair is considered class evidence.
3. Explain the solution to your crime scene evidence.
REFERENCES:

Clifton Meloan, Richard James, Richard Saferstein. (1990). Criminalisties: An Introduetion
to Eocensie Science Lab Manual. New Jersey. Prentice Hall.

Schlitz, Gary. (1994). Forensic Laboratory Seienee and Detectixe Mystenr Writing. Illinois.
Flinn Scientific, Inc.

Siegel, Jay. Eorensie Seienee Lab Manual. Michigan State University, East Lansing.
Michigan. 1993.

Revised by Karen Pawloski

ANALYSIS OF FIBERS

Fibers can be very important pieces of evidence in incidents that involve personal contact -
such as homicide, assault or sexual offenses. The ultimate value of a fiber depends on the
ability of a criminalist to narrow the origin to few sources or even a single source. In this
lab exercise you will use several techniques to identify different fibers.

MATERIALS:
Fabric samples filter paper
cotton bunsen bumer
linen ring stand
silk test tube clamp
wool red litmus paper
dacron blue litmus paper
nylon test tubes 13 x 100 mm
orlon Norlands 65 oil
acetate 1.53 Cargille Refractive Index Oil
6 M NH4OH 1 large test tube
6 M H2804
6 M HCl
Pasteur pipets
PROCEDURE:

PART A: Microscopic Examination.
1. Place 2-3 cotton fibers on a clean microscope slide.
2. Place 1-2 drops of glycerin onto the fibers.
3. Cover with a coverslip.
4. Observe using a compound microscope.
5. Sketch what you see in your lab notebook

6. Repeat steps 1 -5 for the remainder of the fabrics listed above.

PART B:

PART C:

103

Fiber cross sections

. Obtain 2-3 cotton fibers.
. Thread them 2-3 em up the tip of a Pasteur pipet.

. Pour one or two drops of Norlands 65 into the pipet from the top and allow

to run into the tip.

. When the tip is full cure the Norlands under long wave UV light for 15 minutes.

. With a single edge razor blade, chip away the glass of the tip and cut a thin

section of the Norlands and fiber.

. Mount in a drop of 1.53 Cargille Refractive Index Oil with a coverslip.
. Observe under the microscope.
. Sketch what you see in your lab notebook.

. Repeat Steps l-8 for the remaining fibers.

Effect of heating

. Prepare the apparatus shown on the next page. See Figure l.

a. Carefully insert a strip of cotton fabric into the bottom of a test tube.

b. Insert a strip of both damp red and blue litmus in the top of the tube.
Be careful to ensure that the strips do not touch each other.

e. Cover the test tube with a piece of filter paper.

104

 

 

 

 

 

Figure l: Litmus Set-Up

2. Gently heat the test tube and its contents.

3. Observe the effect of the heating on the litmus papers.

4. Repeat steps 1-4 for the remainder of the fabrics listed on page 1 of this activity.
5. Prepare a chart showing the results of this testing for all of the fabrics.

PART D: Effect of burning on fabric.

1. Pick up a small piece of cotton fabric with a pair of tweezers or forceps.

2. Place in the flame of a bunsen burner.

3. As the fabric burns, evaluate the odor, rate of burning, kind of flame and type of
residue.

4. Repeat for the remainder of fabrics listed on the previous page.

5. Prepare a chart comparing the odor. rate of burning, kind of flame and type of residue
for all of the fabrics.

105

SOLUBILITY:
1. Cut a 1 cm x 8 cm piece of cotton fabric into small pieces.

2. Divide the fabric into 4 sections and place into four small test tubes or four wells on a
spot plate.

3. Using a Pasteur pipet put twenty drops of 6 M NH4OH into the first test tube.

4. Using a Pasteur pipet put twenty drops of 6 M HCl into the second test tube.

5. Using a Pasteur pipet put twenty drops of 6 M H2804 into the third test tube.

6. Using a Pasteur pipet put twenty drops of water into the fourth test tube.

7. Allow to react for at least five minutes.

8. Record the results in your lab notebook.

9. Repeat steps 1-8 for the remaining seven fabrics.

10. Prepare a chart comparing the solubility of the fibers in the four compounds.
DATA: Prepare data tables in your lab notebook as indicated above.
QUESTTONS: '

1. Are synthetic or natural fibers easier to identify?

2. Do synthetic and natural fibers appear the same, microscopically?

3. Why was water one of the chemicals used in the solubility lab?

4. What did we use litmus paper in this lab?

106

REFERENCES:

IheChemrsnyofKeeningCleanJeachetsGuide AModuleinHighSchoolScienee.
(1989). Michigan State University. Lessons 18-22.

Clifton Meloan, Richard James, Richard Saferstein. (1990). Cnminalistics: An Introduction
to Eorensic Science Lab Manual. New Jersey. Prentice Hall.

Schlitz, Gary. (1994). Forensic Laboratory Science and Detective Writing. Illinois. Flinn
Scientific, Inc.

Siegel, Jay. (I993) Forensic Science Lahotatotx Manual. Michigan State University. East
Lansing, Michigan.

Revised by Karen Pawloski

CARPET SAMPLE LAB

The examination of hair and fibers can systematically be completed in the crime lab if the
fibers are given to the scientist. Many times however it is the job of the scientist to
investigate and find the evidence from vacuum bags and carpet samples. In this lab you
will be given a carpet sample which has evidence irnbedded in it. Your job is to find the
evidence, do a cursory analysis of it and then develop a plan to determine the identity of it.
Upon completing the development of the plan you can begin to implement the plan.

Your ultimate goal is to identify the type of hair or fiber you have and document all testing
procedures and conclusions which led to your final evaluation.

References:

Pawloski, Karen. (I996) Forensic Science in the High School Classroom Michigan State
University, East Lansing.

107

DETERMINATION OF LIPSTICK DYES USING TLC

The examination of lipstick stains left on clothing, glass, napkins and cigarettes provide
valuable clues as to the identity of a suspect. Lipsticks are composed of fats, oils, waxes,
colorings, perfumes and flavorings. The color of a lipstick is mainly due to aluminum,
calcium or barium dyes in concentrations between 15% and 20%. By first extracting the
dyes from the stained material the forensic chemist can then separate the dyes by TLC.

CRIME SCENE

The Michigan State Flag is missing from Mrs. Pawloski's room. It appears that some
delinquent has forcefully entered the building last night. A search of the premises revealed
a scrawled note across the window in lipstick, "Michigan and mathematics rule". After
photographing the note the lipstick will be removed using kirnwipes. All three female
mathematics teachers are suspects in this horrendous deed. Mrs. Pawloski has confiscated
the lipstick from the three suspects. Your job is to analyze the three confiscated lipsticks
and the note lipstick and determine which, if any, of the teachers committed this crime.

OBJECTIVES:

The student will separate lipstick dyes using thin layer chromatography.
The student will calculate Rfvalues from their thin layer chromatography plate.

MATERIALS:

beaker, 250 ml methanol

stirring rod isoamyl alcohol

graduated cylinder, 10 ml acetone

pipet, 1 ml distilled water

scissors ammonium hydroxide

test tube rack lipsticks

4 test tubes, 13 x 100 mm evidence on Kimwipes or window
TLC plates metric ruler

forceps filter paper, 12 cm

micropipettes, 25 ul

108

109

PROCEDURE:

1. Obtain a piece of stained Kirnwipe. Using scissors cut a l x 2 cm section into small
pieces.

2. Place the pieces into a small test tube with 5 drops of methanol. (The pieces should
be wet and there should be some liquid in the tube. If not add more methanol.)

3. Now make three stained Kirnwipes using the three suspected lipsticks.

4. Cut out a l x 2 cm section of each marked Kirnwipe and place in a small test tube with 5
drOps of methanol.

5. Prepare a chromatographic plate by notching the ends as shown in Figure 1. This
notching forces the solvent to move through a narrow space, with the result that the
dyes will appear as thin bands of color well separated.

 

   
 

 

 

 

 

Paras-Film
TLC.
TLc L"falter Cr
Plocte p lCLT‘E» L 90L?
' ° ° ' ‘ Solveln‘l’

 

Figure 1 Figure 2

6. Using a micropipette transfer 10 drops of the eluted lipsticks onto the thin plate between
the notches. Be sure to allow each drop to dry thoroughly before adding the next
drop. Make sure you document which drop is which lipstick as shown in the
diagram. You will have a total of 4 separate dots.

*** The lab made be interrupted at this point and finished another day.

7. Prepare the developing solvent. Mix 5 ml of isoamyl alcohol, 5 ml of acetone, 3.2 ml
distilled water and 0.1 ml of ammonium hydroxide in the 250 ml beaker. Stir with
the stirring rod vigorously, but being careful, to ensure mixing.

8. Place a piece of filter paper into the beaker. The filter paper should be leaning against
the wall of the beaker with a small portion submerged in the solvent. The paper
will absorb some of the solvent and make the entire atmosphere of the TLC
chamber like the solvent. Cover the beaker with parafilrn. See Figure 2.

110

9. Hold the spotted plate next to the chamber to be certain that the colored spot is above
the solvent line rather than immersed within.

10. Uncover the chamber and place the TLC plate into it. Replace the parafilrn and allow
to stand undisturbed until the solvent reaches the end of the plate.

1 1. Remove the plate and mark the solvent front by making a notch in the TLC plate.
12. Allow the plates to dry and compare the dyes on each.

13. Measure each band {tom the point of application.

14. Measure the solvent front from the point of application.

15. Calculate the Rfvalues.

Rf :
distance of solvent front from application point

16. Compare the evidence with the three known chromatograms.
DATA:

Draw and label each of the chromatography plates. Show the distance moved and
calculate the Rfvalues.

CONCLUSIONS:

State who is the likely suspect and why.

QUESTTONS:

1. Why did the lipstick extracts move to different places on the TLC plates?
2. Does this evidence unequivically prove the origin of the note?

3. What other types of crimes might utilize this forensic technique in their solution?
Suggest a scenario.

lll

FURTHER INVESTIGATIONS:

Develop a technique for the analysis of other dyes, such as inks or blushes.
REFERENCES:

Clifton Meloan, Richard James, Richard Saferstein. (I990). Criminalistics: An Introduction
to Forensic Science Lab Manual. New Jersey. Prentice Hall.

Rost, Carolyn. (1990). Lab Manual. Michigan State University. East Lansing, Michigan.

Siegel, Jay. (1993). Forensic Science Lab Manual. Michigan State University. East
Lansing, Michigan.

Revised by Karen Pawloski

THE ANALYSIS OF QUESTIONED DOCUMENTS

The analysis of questioned documents (QD) represents one of the few "apprenticeship"
fields left in forensic science. By this, it is meant that this area is learned mainly by
studying with an experienced QD examiner. There is not much in the way of formal
education in this field. Because of the nature of instruction in questioned document
analysis, apprenticeships tend to be long and in some cases may be up to 3 years before the
trainee is permitted to work on cases solo. By the same token, some of the popularity of
this area lies in the opportunities for QB examiners to engage in civil work outside the
criminal field, thus enhancing their income.

The great challenge in questioned document analysis lies in the fact that in aniving at a
decision concerning a case, the examiner has only his/her own knowledge, skill and
experience to draw upon. This contrasts with most other areas of forensic science where
there are analytical instrumental techniques which can be used to aid the examiner in
reaching conclusions. The complete reliance upon one's own skills puts a great burden
upon the examiner.

The purpose of this experiment is to acquaint you with some of the types of QD cases and
analyses which the examiner must confront. Since you are not an expert in this field, the
exercises are fairly straightforward and basic. They include some analysis of handwriting
characteristics, attempts at forgery and analysis of inks.

MATERIALS:

Kit for determining handwriting spacing and slants
Samples of handwriting
TLC apparatus

PROCEDURE:
PART A: Handwriting analysis

During the first class period you were given some dictation which was subsequently
collected from you. This is the material which will now be given back to you for analysis.
You will be furnished with a "questioned document" and a series of exemplars from
different sources. Using the knowledge you have gained from lecture and the slant and
spacing analysis kit, you are to decide which, if any, of the knowns came from the same
source as the unknown. Some of the characteristics of the handwriting you may want to

112

113

look at are slant, intraletter and interword spacings, relative sizes of letters, loop
characteristics, proportional size of letters, and unusual characteristics. Remember there is
not a set number of characteristics which must be determined in order to arrive at a
conclusion. The number is up to the examiner. It is also true, however, that the more
characteristics found, the better the result.

PART B: Forgery

Get a member of your group to fumish you with a copy of his/her signature. Practice
forging the signature until you are proficient in doing so without looking at the real
signature. Then try forging the signature by tracing over it on another sheet of paper.
Compare the forgeries to see if you can determine which ones are traced. Turn in your best
forgery efforts along with the real signature.

PART C: Thin Layer Chromatography of Inks

See next page.

ANALYSIS OF INKS BY THIN LAYER CHROMATOGRAPHY

This experiment will demonstrate a technique used by forensic scientists. The purpose is to
identify colored pigments in pen inks. The need for differentiating inks arises when people
prepare fraudulent documents, send ransom notes or threaten others in written form. For
example, a student may change an answer on another student's paper. Similarly, a person
may attempt to forge an absence note from their parent. Handwriting analysis and the
ability to differentiate inks will often permit the forensic scientist to prepare a document
and perhaps locate the owner of the pen itself.

Modern day inks are actually composed of mixtures of dyes. These dyes can be separated
by TLC. Thin layer chromatography utilizes a thin film of silica gel coated onto a glass of
plastic strip. As in paper chromatography, this thin film is called the stationary phase. A
mixture of the compound to be separated, in this case inks, is placed in a small spot at one
end of the strip, and a liquid, an organic solvent, the mobile phase, is passed over the spot.
The chromatographic developing chamber is a small beaker covered with parafilrn. As the
solvent moves up the strip, it carries the different components within the ink. Because each
compound present has a different Size, shape and electrical field, each compound will
adhere to the stationary phase and dissolve in the mobile phase to a different extent. After
a period of time the flow of the mobile phase is stopped, the strip is dried and the pigment
distance is measured. The distance the pigment moves relative to the distance the mobile
phase moves is called the Rfvalue.

CRIME SCENE

Mary Williams is receiving threatening notes on her locker. Although she is unsure who is
at fault she suspects Terrible Teresa who has been harassing her in Geometry class. Mary
has called in the Forensic Crime Team to help solve the crime. How might we go about
proving who is responsible for this tenible deed? What suggestions might you propose?

114

115

MATERIALS:

3 test tubes, 13 x100 mm
graduated cylinder, 10 ml
scissors

test tube rack

forceps

beaker, 250 ml
micropipettes, 25 ul

TLC plates

parafilrn

PROCEDURE:

methanol
n-butanol
distilled water
isopropanol
pens

written note
metric ruler
filter paper

1. Obtain a piece of the handwritten note. Using scissors cut five words into small pieces.

2. Place the pieces into a small test tube with three drops of methanol. More methanol
may need to be added if the paper pieces soak it all up.

3. Make a heavy pen mark on a piece of paper with each of the three pens provided.

4. Cut out each mark and place in separate small test tubes with three drops of methanol.

5. Prepare a chromatographic plate by notching the ends as shown in the diagram. See
Figure 1. This notching forces the solvent to move through a narrow space, with
the result that the dyes will appear as thin bands of well separated color.

 

TLC.
'Pldrle.

To... 4

 

 

 

Figure 1

 
  

—- 'f-i Her" paper
“TLC. Filed-e.

 

6. Using the micropipette, transfer three drops of the eluted inks onto the thin plates
between the notches. Be sure to allow each drOp to dry thoroughly before adding

the next drop.

*** The lab may be interrupted at this point and held until the next day.

116

7. Prepare the developing solvent. Mix 10 ml of n-butanol, 5 ml of isopropanol and 5 ml
of distilled water in the 250 ml beaker.

8. Place a piece of filter paper against the inside wall of the beaker with it's bottom edge
touching the developing solution. Some of the solution will be absorbed by the
filter paper creating an atmosphere similar to the solvent in the chamber. Cover
the beaker with parafilrn.

9. Hold the spotted plate next to the chamber to be certain that the colored spot is above
the solvent line rather than immersed within.

10. Place the TLC plate in the developing chamber with the silica gel side facing away
from the filter paper. Cover and allow to stand undisturbed until the solvent
reaches the top of the plate.

I 1. Remove them and make a notch to mark the solvent front.

12. Allow the plates to dry and compare the dyes on each.

13. Measure each band from the point of application.

14. Measure the solvent front from the point of application.

15. Calculate the Rfvalues.

Rf=l' E 11 111 1.. .

distance of solvent front from application point

16. Compare the known ink chromatograms with your handwritten note and determine
the origin of the document.

DATA:

Draw and label each of the chromatography plates. Show the distance moved and
calculate the Rfvalues.

CONCLUSIONS:

State which pen was used to write the threatening note.

117

QUESTIONS:

1. Why did the inks move to different places on the TLC plates?

2. Does this evidence unequivically prove the origin of the note? Why or why not?
REFERENCES:

Rost, Carolyn. (1990) Lab Manual. Michigan State University. East Lansing, Michigan.

Clifton Meloan, Richard James and Richard Saferstein. (1990). Criminalistics: An
Introduction to Forensic Science Lab Manual. New Jersey. Prentice Hall.

Siegel, Jay. Forensic Science Lab Manual. Michigan State University, East Lansing,
Michigan 1993.

Revised by Karen Pawloski

VISUALIZATION AND EXAMINATION OF FINGERPRINTS

The science of dactylosc0py, or the study of fiiction ridges is one of the most important
methods of personal identification available to the criminal justice system. Friction ridges
include finger, palm, foot and lip prints, but the most important is, of course, fingerprints.

There are a number of components to dactylosc0py. They include:
1. Visualizing latent (invisible to the naked eye) prints on a variety of surfaces.
2. Transferring a visualized print to a tape or a card.
3. Obtaining known prints by inking.
4. Comparing inked (known) prints with unknown prints, either latent or patent
(visible to the eye without development.)
5. Perform a classification of a set often fingerprints using FBI system.

In this experiment, you will learn about several ways of visualizing latent fingerprints.
You will also compare an inked print with a visualized latent print. Finally, you will
perform an FBI classification on a set of 10 prints.

MATERIALS:

fingerprint powders and brushes
lifting tape and cards

ink pads

magnifying glasses

FBI card

set of unknown fingerprints

PROCEDURE:
PART A:
Have a partner roll your right thumb print onto a white index card. Repeat until

you obtain a non - smudged print. Write your name on the card and turn the card
in to Mrs. Pawloski.

118

119

PART B: Dust and Lift
1. Run your fingers through your hair to increase the amount of oil on your fingers.

2. Deposit some fingerprints on surfaces such as a beaker, glass plate or a piece
of paper.

3. Using a powder that contrasts in color with the object that you are dusting,
lightly dust the print.

4. Examine the dusted print with a magnifier to see if you can clearly see and count
the ridges. This is the basis for comparison of fingerprints.

5. Using lifting tape, lift one of your best dusted prints. Start by putting the tape
down on the left side of the print. Then, using a finger as a roller, push
the tape down across the print in one motion.

6. Lift the tape and transfer it to a contrasting card (black or white side).

7. Tape the print to the card.

PART C: Silver nitrate visualization.

1. Spray or brush an object with a silver nitrate solution (5 g AgNO3 in 100 ml

of distilled water). Since fingerprints contain some sodium chloride,
insoluble silver chloride will form and be deposited along the friction
ridges.

2. Wash the object in water (gently) to remove the excess Silver nitrate and
put in a drawer (complete darkness) to dry.

3. After the object dries, put it in the light. Light will catalyze the decomposition
of silver chloride to from free silver which is black.

4. After the print outlines are black, dip the object into photographic hypo
clearing agent to remove the excess silver chloride and fix the silver
image. Failure to fix the silver will result in its turning the print completely
black.

120

PART D: Fingerprint comparison
Using the same finger that made your best dusted and lifted print, make an
inked impression on a piece of paper. Find at least 12 points of identification
on the two prints and label them with lines and numbers.

PART E: FBI classification

1. Using the FBI fingerprint card given you, make an inked set of prints for you
and your partner.

2. Classify each of your fingerprints as the fingerprint type (ulnar loop, tented arch,
plain whorl, etc.).

3. Using the information from step 2 detemrine your FBI primary classification.
PART F: Unknown detennination

1. Obtain a sheet of fingerprint unknowns from Mrs. Pawloski.

2. Determine which print is your own.

3. Find at least 12 points of comparison between the selected unknown print
and your inked print. Label them with lines and numbers.

DATA:

Submit the following to Mrs. Pawloski:
1. Example of dust and lift - matched to 12 points with a known inked print.

2. FBI card with fingerprint types and FBI primary classification.
3. Matched unknown print.
QUESTTONS:

1. Why is doing an FBI primary classification on a set of prints useful to a
fingerprint examiner?

2. What works better when rolling a set of prints, a little or a lot of ink?
Why?

121

3. Look at the set of unknown prints from our class, what print type is
most common? What is least common?

4. Write the chemical equation for the reaction of silver nitrate with the sodium
chloride on our skin.

REFERENCES:

Siegel, Jay (1993). Forensic Science Lab Manual. Michigan State University. East
Lansing, Michigan.

Revised by Karen Pawloski

SHOEPRINTS

Among the types of evidence which is individualized to a particular source are shoeprints
and tire treads. The print or tread must be left in a material which is capable of "holding" it
after deposition. Certame the most common among these substances is soil. In a typical
case, a shoeprint from a shoe which has some characteristic tread pattern is deposited in
soil. A cast of the print in the soil is made and then compared to the pattern in the shoe. In
this case, older worn shoes are much easier to individualize than are brand new shoes
because the former have undergone random wear and tear which is not expected to be
reproduced exactly on any other shoe sole. If enough of thesecharacteristics can be
captured by the cast, then the shoe can be individualized to the cast and hence, the imprint.

MATERIALS:

quick dry plaster
bucket, water, etc.
twigs or metal screen
camera ‘

PROCEDURE:

1. Depending on the weather, you may be able to make a shoeprint outside in a patch of
dirt, otherwise use the plastic tub of dirt in the laboratory. Using a shoe with a
tread pattern, preferably one that shows some wear and tear, make an impression
by walking through the dirt patch or tub of soil.

2. When you are ready to take the impression, make enough plaster to cover the entire
impression and leave a six inch border all the way around it. Use only enough
water with the plaster to make a thick paste. Pour in the plaster to a depth of
about 1 inch and then lay several twigs or some metal screen on top of the cast.

- It is a good idea to have the twigs extend out from the border so that they can be
used to grasp the cast while carrying it. Then pour another inch or so on top of
the twigs or screen to complete the cast.

3. When the plaster sets (about 30 min), remove the cast and put it in the lab, impression
side up and leave alone for at least 24 hours.

123

4. Gently scrape off all dirt and debris from the impression. You may use water to wash
off the residue but scrape off as much as possible into a trash receptacle first so that
you avoid putting too much dirt down the sink drain.

5. Using printers ink, ink the bottom of the shoe and make an impression on a piece of
blank white paper. Then compare the inked impression and the cast by finding
and marking unique points which help to individualize the shoeprint and the shoe.

6. Photograph the inked impression, the shoe and the cast. The pictures you take which
are labeled with the points of ID, will be your evidence in court of your match.
Find as many points of identification as you can.

DATA:

Turn in your inked impression and your plaster cast.
Turn in your points of comparison.

QUESTIONS:

1. Besides plaster, what other materials could be used to lift a shoeprint impression?
What are their relative advantages and disadvantages?

2. Describe a suitable method for making a shoeprint cast from an impression in the snow.

REFERENCES:

Siegel, Jay. (1993). Forensic Science Lab Manual. Michigan State University. East
Lansing, Michigan.

Revised by Karen Pawloski

URINE ANALYSIS USING PAPER CHROMATOGRAPHY

Chromatography techniques are methods used to physically separate mixtures of gases,
liquids, or dissolved substances. Separation is determined by the molecular size and/or
charge of the individual components in the sample mixture.

All forms of chromatography have two things in common: a stationary (absorbent) phase,
and a mobile phase. The stationary phase is the material on or in, which the separation
takes place. The paper is the Stationary phase in paper chromatography. The solvent is the
mobile phase that dissolves the sample forming a solvent-sample mixture and transports the
sample over the stationary phase to facilitate the separation of the components.

The sample is first placed on the paper at a fixed point. The tip of the paper is then placed
in the solvent, taking care not to immerse the sample itself. The solvent, "carrying" the
sample with it, begins to travel up the paper. As it does, the individual sample components
may travel at different rates and separate. The components that are held less "tightly" by
the stationary phase will travel the fastest.

The distance each component travels from the origin is called the solute front, and the
distance the solvent travels is called the solvent front. The ratio of these measured values is
called the Rf(rate of flow) value. These ratios are determined by the formula:

Rf=disrancesolluetraxeled

distance solvent traveled

In paper chromatography the rate at which individual components move is related to how
easily each component is dissolved by the solvent (mobile phase) being used. Whichever
component is most easily, and most completely, dissolved by the solvent is the component
that will move the farthest in the time allowed. Some other factors that may influence how
fast and far a component moves are: molecular size (with smaller molecules moving faster),
electrical charge, and how great an "attraction" (usually determined by charge) the
component has for the stationary phase. In paper chromatography solubility is the most
important factor and the most soluble component will have the highest Rf value.

The Rfvalue for each component is unique and can be used to identify individual
components when compared to known standards.

125

MATERIALS:

chromatography paper food coloring:

two sheets plain white paper blue

eye protection red

1000 ml beaker yellow
scissors green
pencil (not pen) four capillary tubes
distilled water ruler

tape paper toweling

"the food color simulates urine samples“

PROCEDURE:

1. Add 100 ml of water to the beaker.

2. Cut four pieces of chromatography paper 17.5 cm in length (width should be 2.54 cm).
3. Cut one end of each piece diagonally twice to form a pointed end similar to a stake.

4. Use a pencil to draw a line perpendicular to the length of the chromatography paper;

2.54 cm from the bottom of the tip as shown in Figure 1. This will be the
sample origin.

Slumplc
Origin

 

”Sample. to be.
sapocroc't-Ld

 

 

5. Mark a small dot at the center of this origin line with pencil.

6. Label the top of each of the four pieces of chromatography paper with one of the
apprOpriate food 2 zlors that are to be separated.

7. Use a capillary tube (be sure not to mix the tubes) to transfer a small amount of the food
coloring to the dot. Let the sample dry for 30 seconds and repeat this transfer two
more times.

126

8. Allow the sample to dry for one minute after the final transfer.

9. Repeat steps 7 and 8 for the remaining three colors - each on a separate strip of paper.

10. Gently slide the pointed end of each strip down the interior of the 1000 ml beaker until
the tip comes in contact with the water. Make sure the sample doesn't come in
contact with the water.

I 1. Bend the upper end of the paper over the rim of the beaker and tape if necessary.

12. Allow approximately 15 - 20 minutes for the fool colors to separate. Watch the
progression of the solvent front, and let it move to within 1 or 2 cm of the beaker

um.

13. Remove the chromatography paper from the beaker after the samples have separated
and place it on paper toweling to dry.

14. Use a pencil to draw a perpendicular line representing the farthest distance traveled by
the solvent. This is your solvent front.

15. Tape two paper strips on a 8 1/2 x l 1 inch piece of white paper. Place the tape above
the solvent front and below the origin. Your partner should do the same for the
other two strips.

16. When the samples have dried, use a pencil to draw perpendicular lines through the
middle of the separated components. This is the solute front.

17. Measure the distance from the origin to the solute front for each component.
Measure the distance from the origin to the solvent front for each strip.

18. Wash hands thoroughly with soap and water.

DATA: .

Draw a diagram of each of the four strips showing their band patterns.
QUESTIONS:

1. Calculate the Rfvalues for all separated components.

2. Why is pencil used instead of pen?
3. How many components does each sample have?

127

REFERENCES:

Schlitz, Gary. (1994). Forensic Laboratory Science and Detective Writing. Illinois. Flinn
Scientific, Inc.

Revised by Karen Pawloski

OUCHTERLONY DIFFUSION

Blood is often left at the scene of a crime. The criminalist must be prepared to answer the
following questions when examining blood:

1. Is it blood?

2. Is it human blood?

3. If it is human can we characterize the blood type?

The simulated blood samples we are using today have been characterized as blood. This
was accomplished by treating the stain area with phenophthalein. When blood stains,
phenolphthalein and hydrogen peroxide are mixed, the blood's hemoglobin will form a
deep pink color.

Once the stain has been characterized as blood the researcher must determine if the stain is
human. Today we will use the ouchterlony diffusion method to simulate this type of
identification. This test is based on the fact that when animals (usually rabbits) are injected
with human blood, antibodies are formed that react with the invading human blood. The
investigator can recover these antibodies from the rabbit by bleeding the animal and
isolating the sera. This rabbit serum will contain antibodies that specifically bind to human
antigens. For this reason, the serum is known as human antisertun. In the same manner, by
injecting rabbits with other known animals blood other antisera can be produced.

Today we will utilize the process of gel diffusion, taking advantage of the fact that antigens
and antibodies will move toward each other on a gel plate. Here, the extracted bloodstain
and the human antiserum are placed in separate wells opposite each other on the gel. If the
blood is of human origin, a line of precipitation will form where the antigens and
antibodies meet. This test is extremely sensitive and requires only a small thread of blood
soaked material. Human bloodstains dried as long as 10 - 15 years still provide positive
results. Extracts from mummies 4000 to 5000 years old have given positive reactions.

129

MATERIALS:

small petri dishes - 35 mm l/student pair
soda straws

wax pencils

agarose

NaCl

human antibody ( 0.5 M N82804 )

human antigen ( 0.5 M BaC12 )
simulated blood soaked cloth

same cloth, unstained

pasteur pipets

PROCEDURE:

PART A: Preparation of the ouchterlony media.

I. Dissolve 1.76 grams ofNaCl in 200 ml of distilled water.

2. Dissolve 2.4 grams of agarose in the saline solution. It will be necessary to heat the
agarose solution to cause the agarose to dissolve.

3. Pour enough agarose solution into each petri dish to cover the bottom of the plate
to a depth of about 5 mm.

4. Allow the plates to cool overnight.
PART B: Preparation of the ouchterlony wells.

1. Using the template in Figure 1, as a guide, cut small well with a soda straw in the
agarose.

2. Carefully remove the wells with a Pasteur pipet.

I30

3. Mark 12:00 o'clock with a wax pencil on the dish containing the wells and familiarize
yourself with the standard numbering system provided in Figure 1. Notice
it is not necessary to number the wells on the dish since the mark can be used
as a reference point.

  

PART C: Filling the wells.
1. Fill the center well with three drops of human antibody.

2. Place a 1 cm square of stained cloth in a test tube. Add 5 drops of water and
stir thoroughly.

3. Place a 1 cm square of unstained cloth in a test tube. Add 5 drops of water and
stir thoroughly.

4. Fill well #1 with 3 drops of the questioned stain antigen, well #3 with 3 drops of the
known human antigen and well #5 with 3 drops of the unstained cloth eluate.

5. After you have filled the wells allow the plate to develop for 30 minutes.

PART D: Recording results.

1. Look through the bottom of the plate while holding it up to a bright light.

2. Make a drawing of the plate and the results that you observe. If the reaction is
positive, a precipitin line will have formed between the center well and the
adjacent well. Make a "+" (positive reaction) or "-" (negative reaction) in
the space between the wells.

DATA:

Make a drawing of the plate showing the results.

131

QUESTIONS:

1. Why is it necessary to eluate the unstained cloth?

2. What firrther tests would the criminalist perform with this blood sample?

3. Explain the antigen-antibody response.

TEACHER'S GUIDE:
To prepare the blood soaked cloth, soak a piece of cloth in a l M barium chloride
solution mixed with red food coloring.

REFERENCES:

Clifton Meloan, Richard James, Richard Saferstein. (1990). Criminalistics: an Introduction
to Forensic Science Lab Manual. New Jersey. Prentice Hall.

Rost, Carolyn. (1990). Lab Manual. Michigan State University. East Lansing, Michigan.
Washbum, Sherwood 1.; The evolution of man. Sci. Amer. September: 194 - 208: 1978.

Revised by Karen Pawloski

DETERMINATION OF THE PEAK ABSORBANCE OF A SUBSTANCE USING
VISIBLE SPECTROPHOTOMETRY.

Visible spectrophotometry is the measurement of the amount of light absorbed by a colored
solution, the amount absorbed being proportional to the concentration of the compounds in
the solution. Each colored compound has a select few wavelengths that it will absorb in
preference to other wavelengths. Therefore, by carefully selecting these wavelengths, it is
often possible to measure the amount of one colored compound in the presence of others.

In this lab, you will determine the wavelength that a colored solution will maximally
absorb. To do this you will make a series of dilutions of methylene blue dye and test each
dilution at a range of wavelengths. The absorbance values will then be plotted on a graph
of absorbance versus wavelength and a peak wavelength will be established.

MATERIALS:

7 - Spec 20 cuvettes
distilled water
.025% methylene blue stain
(prepare by serial dilution of . 1% stain)
Spectrophotometer

PROCEDURE:

PREPARATION:

1. Turn on Spectrophotometer to allow time to warm up.

133

2. Serially dilute a 0.025% solution of methylene blue stain into 6 cuvettes as follows:

a. Place 4 ml of .025% methylene blue in the first cuvette.

b. Transfer 2 ml of the .025% methylene blue solution from
the first cuvette to the second cuvette.

c. Add 2 ml of distilled water to the second cuvette.

(1. Mix the solution in the second cuvette thoroughly.

e. Repeat this process from cuvette 2 to 3 and so on
until all six cuvettes have solution in them.

f. Determine the percent of methylene blue in each tube.

3. Prepare a blank by placing 4 ml of distilled water in the seventh cuvette.

TESTING:

I. Set the spec 20 to a wavelength of 340 nm.

2. With the sample chamber empty and the cover closed, use the power switch knob
on the left to set the meter needle to infinity absorbance. (When the chamber
is empty, a shutter blocks all light from the phototube.)

3. Wipe the blank free of fingerprints and moisture with a Kirnwipe. Insert the tube into
the sample holder, close the cover and set the meter to zero absorbance using
the right knob.

4. Repeat steps 2 and 3 until the readings are repeatedly correct. (Without the blank
the instrument should automatically go back to infinity absorbance and with
the blank to zero absorbance.)

5. Wipe cuvette 1 free of fingerprints and insert into the sample holder.

6. Read the absorbance at 340 nm and document.

7. Change the wavelength by 20 to 360 nm.

8. Read the absorbance and document.

9. Repeat steps 7 - 8 (i.e. change by increasing 20) until a wavelength of 700 nm is
reached.

I34

10. Remove cuvette 1 from the sample holder and repeat steps 2 - 4.
11. Repeat steps 5 - 10 for the remaining five cuvettes.
DATA:

1. Prepare a data table of wavelength and absorbance for all six cuvettes.

2. Plot the absorbance (y-axis) vs. wavelength (x-axis) on a graph.
Data for all six tubes can be plotted on one sheet of graph paper.
Different colored pencils can be used to represent each tube.
After plotting the data, connect the dots using snaight lines.

CONCLUSION:

Look at your graph of the data and determine the maximum absorbance for each tube.
You should see a common peak between all six of the tubes.

QUESTIONS:

1. What was your peak absorbance value?

2. Why did you determine this?

3. Suggest sources of error in this experiment.
REFERENCES:

Clifton Meloan, Richard James, Richard Saferstein. (1990). Criminalistics: An Introduction
to Fonensic Science Lab Manual. New Jersey. Prentice Hall.

Pawloski, Karen. (1996). Forensic Science in the High School Classroom. Michigan State
University. East Lansing, Michigan.

IDENTIFICATION OF SALICYLATES IN BLOOD BY SPECTROSCOPY

Visible spectroscopy allows the researcher to measure the amount of light absorbed by a
colored solution, the amount absorbed being proportional to the concentration of the
compounds in the solution. Each colored compound has a select few wavelengths that it
will absorb in preference to other wavelengths. Therefore by carefully selecting the
wavelengths desired, it is often possible to measure the amount of one compound in the
presence of several others.

Salicylates react with ferric salts to produce a violet color, which is proportional to the
concentration of the salicylate. For the detection of the salicylate we will measure light
absorption at 540 nm. Because of the simplicity of this salicylate procedure, the
assumption of salicylate poisoning produces a very strong and easily seen violet color with
the ferric salt reagent.

Our job today involves developing the purple salicylate colors for several known
concentrations, preparing a calibration curve and then determining the concentration of a
salicylate in an unknown. In the second part of the experiment we will determine the level
of salicylate concentration in a blood serum sample.

TURN ON THE SPEC 20 SO THAT IT HAS AMPLE TIME TO WARM UP!

MATERIALS:

Spec 20 ferric nitrate solution, 1%

8 cuvettes nitric acid solution, 0.07M

pipettes, 1.0 ml and 2.0 ml nitric acid solution, 0.039 M

test tube rack salicylic acid solution
(lOmg/dL)

PROCEDURE:

PART I: Basic spectrophotometry and forming a calibration curve.
1. Place six spectrophotometer cuvettes in a small test tube rack. Label.
2. Pipet the amounts of materials into each cuvette as shown in Table 1.1. Calculate the

amount of salicylic acid sample and record the results. Hint: Cuvette 2 has a
salicylate concentration of 0.5 mg/dL.

135

136

3. Set the wavelength dial to 540 nm.

4. With the sample compartment empty, adjust the meter to read 0% T. This is
accomplished by rotating the on-off switch.

TABLE 1: Preparation of Standards

 

100 mg/dL distilled dilute 0.039M
Cuvette l 0.0 2.0 0.0 2.0
Cuvette 2 0.2 1.8 2.0 0.0
Cuvette 3 0.6 1.4 2.0 0.0
Cuvette 4 1.0 1.0 2.0 0.0
Cuvette 5 1.4 0.6 2.0 0.0
Cuvette 6 2.0 0.0 2.0 0.0

 

YOU ARE NOW READY TO TAKE YOUR READINGS

5. Place cuvette 1, the blank in the sample compartment and set the meter at 100% T
(zero absorbance) by adjusting the % T knob.

6. Insert each of the known salicylic acid standards in the sample compartment and
obtain an absorbance reading for each sample.

7. Plot absorbance (A) on the vertical axis of a sheet of graph paper and the concentration
(mg/dL) along the horizontal axis for cuvettes l - 6. Draw the best line through
these points. This is called a calibration curve.

8. Now pipet 2 mL of the unknown solution into a cuvette, and mix with 2 mL of
dilute ferric nitrate. Determine it's absorbance.

137

9. From the calibration curve and the absorbance reading you obtained for the unknown,
determine the concentration of the salicylate in the unknown.

PART 2: Determination of Salicylates in Blood Senrm

CRIME SCENE:

A police officer observes a car moving quite erratically down the highway, and, in fact, it
even crosses over the centerline, forcing another vehicle off of the road. The officer stops
the car, and the driver states that she had a severe headache and had taken some aspirin.
She had trouble removing the safety cap on the bottle while driving, and this had caused
the erratic driving. No aspirin container is found, the driver saying that she threw it away.
The driver denies that she is under the influence of alcohol or other drugs. She is taken to
the hospital, where she voluntarily provides blood for an alcohol and drug test. You now
have a small sample of the blood seriun and are to test it for the presence and/ or
concentration of aspirin.

PROCEDURE:

1. Label two small cuvettes each for both the unknown sample and the lOmg/dL standard.

2. The unknown sample cuvettes will be labeled "test" and "blank," and the standard
sample cuvettes will be labeled "test" and "blank."

3. Into each cuvette, pipet 2.0 mL of distilled water.

4. Into the cuvettes for the unknown sample, pipet 0.2 mL of serum.

5. Into the cuvettes for the standard, pipet 0.2 mL of the 10 mg/dL standard.
6. Into the blank tubes, pipet 2.0 mL of 0.039 M nitric acid.

7. Into the test tubes, pipet 2.0 mL of dilute ferric nitrate solution.

8. Shake all tubes to mix the contents.

9. Let all tubes stand for 5 minutes.

10. Determine the absorbance of each tube using the spectrophotometer. Record the
absorbance on your lab sheet.

138

DATA SHEET
PART A: Basic Spectrophotometry

Concentration of

____salrcylate_(mgldL)____absorbance

Cuvette l

Cuvette 2

Cuvette 3

Cuvette 4

Cuvette 5

Cuvette 6

Absorbance of unknown

Concentration of unknown obtained from graph: mg/dL
Concentration of unknown (obtained from instructor) mg/dL

% error

 

PART B: Salicylates in blood serum

Standard IngZdI, - Absorbance
Standard blank

 

 

Standard 10 mg/dL
Unknown blank

Unknown

 

139

CALCULATIONS:

Use the relationship below to detennine the concentration of salicylate in the unknown
sample.

absorbance of unknown minus absorbance of unknown blank
mg/dL = . x 10
absorbance of standard minus absorbance of standard blank

 

QUESTIONS:

1. Do you suppose that there would normally be salicylate in human blood?

2. Give an example of where this type of procedure might be used elsewhere.

140

TEACHER'S GUIDE:
Materials:
Ferric Nitrate = 1%

Nitric Acid = 0.039 M
5 parts of 0.07 M and 4 parts of distilled water

Nitric Acid = 0.070 M
.29 ml of concentrated acid to 100 ml of water

Salicylic Acid solution:

Dissolve one aspirin per 500 ml of water. Add .15 g of NaOH pellet.
Now take 80 ml of the above and bring to 500 ml. The concentration
of the solution is 10 mg/dL. Test the solution before using with students.

OR

Salicylic stock solution is preferred. Dissolve 0.8 g of sodium salicylate
in a one liter flask. Add a few drops of chloroform as a preservative, then
store in the refiigerator. This solution is equivalent to 50 mg/dL.

Dilute with distilled water for clinical use to 10 mg/dL.

REFERENCES:

Clifton Meloan, Richard James, Richard Saferstein. (1990). Criminalistics: An Introduction
to Forensic Science Lab Manual. New Jersey. Prentice Hall.

Rost, Carolyn. (1990). Lab Manual. Michigan State University. East Lansing, Michigan.

Revised by Karen Pawloski

THE ALCOHOL BREATHALYZER TEST: A LABORATORY SIMULATION

Everyone is familiar with the sight of a motorist pulled to the side of the road by a police
officer. Various physical tests, walking a straight line, touching the tip of the nose with a
forefinger may lead to a suspicion that the driver is under the influence of alcohol. These
dexterity tests alone will not serve as proof in a court of law to establish drunkenness. The
legal proof depends on the results of a breathalyzer test administered to the driver at the
scene. Legally, a person is under the influence when his blood alcohol concentration has
reached a concentration of 0.1 g/ 100mL of blood. The table below summarizes the usual
symptoms associated with various concentrations.

Alcoholconcentrations—__Eficcts

0.05 % None

0.05 - 0.10 % Impaired stereoscopic and night vision

0.10 - 0.15% Euphoria, lack of inhibition, slow
reaction time

0.15 - 0.20% Moderate poisoning, very slow reaction

time, loss of inhibition, disturbances in
balance and coordination

0.20 - 0.25% Severe poisoning, poor balance and
coordination, slow thinking, confusion
0.35 - 0.40% Deep coma, possible death

The chemistry involved in the breathalyzer test is based on the reduction of potassium
dichromate by ethanol in an acidic medium to produce chromium tn'sulfate and acetic
acid. The pertinent balanced equation follows:

3C2H50H + 2K2Cl‘207 + 8H2804 --> 3CH3COOH + 2Cl’2(SO4)3 + 2K2804 +
(yellow) (green) 1 IHZO

In an actual breathalyzer test, the subject must expel 65 mL of ethanol saturated air into a
balloon test chamber containing the dichromate solution. Because of the difficulty working
with gases, we will simulate this using an aqueous solution.

Oxidation of an alcohol to produce a carboxylic acid is a common general reaction studied
in most elementary organic chemistry classes. In this laboratory we will use a

141

142

spectrophotometer to quantify the amount of potassium dichromate which combines with
ethanol to form chromium trisulfate. We will actually be measuring the absence of yellow
from the test tubes.

MATERIALS:

Breathalyzer solution 13 x 100 mm test tubes
0.40% ethanol stock solution graduated cylinder, 10 mL
0.20% ethanol standard parafilm

0.10% ethanol standard Pasteur pipets

0.05% ethanol standard distilled water

unknown ethanol standard spectrophotometer
PROCEDURE:

PART A: Oxidation of ethanol with potassium dichromate
1. Prepare 6 test tubes as follows:
a. Place 2 mL of 0.40% ethanol stock solution into test tube #1. This is your
0.40% standard.
b. Place 2 mL of 0.20% ethanol standard solution into test tube #2.
0. Place 2 mL of 0.10% ethanol standard solution into test tube #3.
(1. Place 2 mL of 0.05% ethanol standard solution into test tube #4.
e. Place 2 mL of distilled water into test tube #5. This is your 0.00% standard.
f. Place 2 mL of your unknown into test tube #6.

** Don't forget to properly label your test tubes.M

2. Place 2 mL of breathalyzer solution into each tube. Cover each tube with parafilm and
invert to mix.

3. Allow the reaction mixture to sit for 15 minutes.
PART B: Reading the absorbance of the samples.

NOTE: The spectrophotometer will need to warm up 15 minutes prior to using it.

143

1. Set the spectrophotometer wavelength to 410 nm.

2. With the sample chamber empty and the cover closed, use the power switch knob on the
lefi to set the meter needle to infinity absorbance. (When the chamber is empty, a
shutter blocks all light from the phototube.)

3. Prepare a blank tube by placing 4 mL of distilled water into a test tube. Wipe the blank
free of fingerprints and moisture with a Kirnwipe. Insert the tube into the sample
holder, close the cover and set the meter to zero absorbance using the right knob.

4. Wipe each sample tube with a Kirnwipe, insert it into the sample chamber and read its
absorbance. Record your data in the appropriate space in the accompanying data
table.

5. Plot absorbance versus concentration on a graph. Draw the best straight line through
your data points. Remember that you may not connect the dots.

6. Find the point on the line which corresponds to the absorbance of your unknown
sample. Read its concentration and report it in your lab write-up.

DATA:

SAMPLE
W

0.00%
0.05%
0.10%
0.20%
0.40%
unknown

QUESTIONS:

1. What sources of error might be present in this procedure? What steps could you take to
correct them?

144

2. Absorbance of a substance is a linear function based on concentration. The formula for
absorbance is called Beer's law ( A = E x b x c ) where E is equal to a constant extinction
coefficient, b is equal to path length of light through the cell and c is equal to molar
concentration. Calculate the extinction coefficient for this reaction.

TEACHER'S GUIDE
MATERIAL PREPARATION:
Breathalyzer solution:
You need 0.123% potassium dichromate in 50% sulfuric acid. To prepare measure .123 g
of potassium dichromate and dissolve it in 100 mL of 50% sulfuric acid.
OR
Measure 1.23 g of potassium dichromate and dissolve it in 100 mL of 50% sulfuric acid.
Take 10 mL of this solution and dilute with 90 mL of 50% sulfuric acid.
Ethanol standards:

To prepare 0.04% ethanol stock solution dilute 0.50 mL of absolute ethanol (95% will
work) diluted to 100 mL with distilled water.

To make the remainder of the standards, do 1 : 1 serial dilutions of the ethanol and water.
Unknown ethanol samples:
Unknown ethanol samples can be made up to any concentration for use. I would

recommend keeping the level to under 0.40%, since concentrations above that are possibly
lethal. The calculation for determining concentration is:

anisohrtionfiesired x desired_%_in_g x _L0_g_solution x LmLethaan
l 100 g solution 1.0 ml solution 0.7907 g

HAZARDS:
Potassium dichromate is a strong oxidizing agent. Concentrated sulfuric acid used at 50%

strength to dilute the dichromate is very corrosive to the skin. In addition, the breathalyzer
solution may stain skin or clothing. The process of dissolving the dichromate in acid is

145

exothermic. The flask will get very hot. Perform the dilution under the firme hood in an
ice bath.

DISPOSAL OF WASTES:

Pour all waste solutions into a large beaker. Add a two fold excess of 50% sodium
thiosulfate and adjust the resultant pH to about 2 or 3 using 3M sulfuric acid. Allow the
mixture to stand for about 1 hour. Neutralize the solution using sulfuric acid or sodium
hydroxide to a pH of 7. Flush the solution down the drain with an excess of water. Dry
any solid residue and dispose of it in an approved manner.

REFERENCES:

Anderson, J .M., Oxidation-Reduction in Blood Analysis: Demonstrating the Reaction in a
Breathalyzer, 1990, J. Chem. Ed, 67:263.

Burke, B.A., Measuring Breath Alcohol Concentrations, JCST, 12/91- 1/92: 176-7.

LaBlanca, D.A., The Chemical Basis of the Breathalyzer: A Critical Analysis, 1990,
J. Chem. Ed., 67L 259-61.

The Alcohol Breathalyzer Test: A Laboratory Simulation, 1989, The Chemistry of Life,
Woodrow Wilson Workshop.

The Alcohol Breathalyzer Test: A Laboratory Simulation, 1992, Cell Molecular Biology,
Towsley Foundation Workshop, Michigan State University.

Timmer, W.C., An Experiment in Forensic Chemistry: The Breathalyzer, 1986, J. Chem.
Ed., 63: 897-8.

Revised by Karen Pawloski

AGAROSE GEL ELECTROPHORESIS USING DYES

The agarose gel is a semi-solid solution that resembles "Jello" and is allowed to solidify in
the gel tray. In short, the students will be loading 7 dyes into small holes made in the gel.
These holes will be referred to as "wells". Afier the dyes are loaded into the wells a power
supply will be connected to opposite ends of the gel. The dyes will immediately begin
migrating through the gel towards a specific electrode.

It is important that students understand the principles involved with the gel electrophoresis.
To put simply, the larger the molecule traveling through the gel, the slower it will travel.
This is exactly how DNA fingerprinting is done. If a gene fragment is smaller than another
fragment, it will run faster and farther through the gel. In this manner DNA fragments can
be separated and compared.

Using the dyes in place of the gene fragments is an excellent way to show the same
principles. The movement of the dyes in this electric field can be used to illustrate the
following:

(1) The migration direction of the dyes can be used to show its overall negative or
positive charge. For example, if the dye migrates towards the positive
electrode (called the anode) the overall net charge of the dye is negative.

(2) To illustrate how some dyes' molecular make-up are somewhat larger than
others by moving slower through the gel.

(3) To show that some dyes can be used as standards to calibrate an agarose gel.
Dyes such as xylene cyanol, bromophenol blue and orange-G are accurate
size markers for small DNA fragments. Remember DNA fragments have
an x-amount of base pairs. The "Base Pair Equivalents" for these dyes are:
orange-G, 70 base pairs; bromophenol blue, 250 base pairs; and xylene
cyanol, 2800 base pairs.

146

147

MATERIALS:

Each team of three will need:

electrophoresis chamber dye samples:

15-50 power supply #1 orange - G

600 mL beaker #2 pyronin - Y

100 mL graduated cylinder #3 phenol red

325 mL of Tris Borate EDTA buffer (TBE) #4 bromophenol blue
300 mL Ehrlenmeyer flask #5 crystal violet

0.5 g agarose (makes 2 gels ) #6 xylene cyanol
heat source ( bunsen burner works fine ) #7 unknown dye mixture
micropipette syringe

PROCEDURE:

PART A: Agarose preparation (makes 2 gels )
1. Tape the ends of the gel tray as described by the teacher.

2. Next tape the comb into place as described by the teacher. Be sure to place the comb
about 1/3 from one end.

3. Place 0.5 g agarose in the 300 mL Ehrlenmeyer flask and then add 55 mL of TBE
buffer.

4. Place the flask on the heat source and bring the solution to a mild boil until all of the
agarose has dissolved.

5. Allow the solution to cool for about 3 - 5 minutes.

6. Using a pasteur pipet, lay a thin bead of agarose where the tape meets the tray and allow
to cool and solidify.

7. Next pour the agarose into the tray to about 1 - 2 mm from the top and allow to cool
until the gel has solidified.

148

PART B: Loading the electrophoresis unit:

1. Carefully remove the comb from the gel. This will leave small holes in the gel. These
small holes are called "wells".

2. Remove the rest of the tape on the ends of the tray.

3. Place the gel tray in the electrophoresis box.

4. Fill the box just to the very top edge of the gel with TBE buffer.

5. Very carefully add the dyes using the micropipette to the wells. Approximately 5
microliters of each will be sufficient. Be sure to draw and label a diagram of the

order of the dyes. The order from the materials list works great.

NOTE: The dyes are more dense than the buffer, so therefore they sink to the bottom of
the wells. Be sure not to overflow the wells.

PART C: Running the electrophoresis.
1. Carefully place the top on the box.

2. Connect the power supply to the electrophoresis top. Be sure not to turn on the power
yet until all leads are connected. Attach the positive electrode (red) to the side of
the tray that has 2/3 of the gel exposed. The negative lead should be attached
to the side of the tray that has only 1/3 of the gel. Turn on the power supply and
adjust it to about 30 volts.

3. Closely watch for the initial migration of the dyes to be sure all of the connections are
satisfactory. The colored dyes should move out of the well and into the agarose
gel.

4. Immediate observations can be made about the net overall charge of the dyes but the
power should be left on until the dye mixture (#7) separates into 3 distinct colors.

149

DATA AND ANALYSIS:

Record your observations in the chart below.

DYE SPEED OF MOVEMENT NET OVERALL CHANGE
#1 orange-g

#2 bromophenol
blue

#3 pyronin-Y

#4 crystal violet
#5 phenol red

#6 xylene cyanol

#7 dye mixture

DISCUSSION AND QUESTIONS:

1. What dyes were positive and which electrode did they migrate towards?

2. Compare the size of gene fragments in terms of the speed that they might travel through
the agarose gel.

3. What were the three unknown dyes in the dye mixture?

4. Of the three dyes that were used as standards, which one of them is probably the biggest
molecule and how can you tell by looking at your gel?

5. Approximately how many base-pair equivalents would you guess phenol red to be?
(Hint: compare it to your standards).

150

REFERENCES:

Forbush, Chris. (1993) Research Project. Michigan State University. East Lansing,
Michigan.

Revised by Karen Pawloski

DNA ELECTROPHORESIS

Electrophoresis is a separation technique based on the observation that a molecule will
migrate in an electrical field. In the case of DNA, a negatively charged molecule, the
migration will be towards a positive pole. If this process can be retarded somewhat by
forcing the molecules to move through a dense medium differences in charge and size of
the molecules can be seen. Gel electrophoresis, used in this lab exercise, provides the
dense material needed.

In order for differences in sizes of DNA to be seen in electrophoresis, the DNA molecule
needs to be cut in some way. Restriction enzymes are used to make these cuts. Restriction
enzymes are specific for certain sequences of base pairs of DNA. They will only cut if the
exact sequence is present. This produces the wide variance in the DNA electrophoresis of
humans.

In this procedure, we will be casting agarose gels, loading the gels with DNA which has
been previously cut with restriction enzymes, placing the gel into an electrical field,
electrophoresing it, and finally staining and destaining the gel. Though this appears to be
very complex, it is actually a very simple technique which has become the basis for DNA
profiling.

MATERIALS:

electrophoresis chamber power supply

TBE buffer ' rrricropipettes, 15 ul

restriction cut lambda DNA loading dye

1% agarose gel 0.025% methylene blue stain
distilled water ruler

staining trays

151

152

PROCEDURE:
PART A: Bufi'er preparation
1. Prepare the buffer according to the following:
Add: 12.1 g Tris Base
0.68 g Boric Acid
0.29 g EDTA
To: 1 liter of distilled water
2. Mix thoroughly.
PART B: Agarose gel preparation
1. Measure 0.5 g of agarose.
2. Add this to 50 mL of TBE buffer prepared in Part A.
3. Heat the agarose, mixing frequently, until the agarose is completely dissolved.
4. Let the solution cool slightly.
5. While the solution is cooling, tape the ends of the gel tray.

6. Tape the comb into place. This will form the wells for placement of DNA samples.

7. Pour the agarose into the prepared gel tray and allow the gel to cool until solidified. (The
gel tray may be wrapped in Saran wrap and refrigerated overnight, at this point.)

8. Remove the comb, carefully, and remove the tape at the ends of the gel tray.

9. Place the gel and the gel tray into the electrophoresis chamber.

10. Pour the TBE buffer into the gel until the gel is completely covered with buffer. The
buffer should just fill the wells. Too much buffer will reduce the current moving

through the gel.

PART C: Sample preparation and well loading.

1. Place 15 ul of the cut lambda DNA into a centrifuge test tube.

153

2. Add 10 ul of loading dye to the DNA in the test tube.

3. Mix by drawing the DNA/dye mixture up and down into the micropipette.

4. Draw 8 ul of the mixture into the pipette. Carefully place the tip of the pipette into the
well. (Generally, you should not use the wells at the very edge unless this can't be
avoided). Slowly inject the mixture into the cavity. Do not puncture the bottom of
the well. Make sure you keep track of which well contains which substance.

5. Repeat step 4 using a different well.

6. Draw 8 ul of the loading dye (not the DNA mixture). Pipette this into another well.

PART D: Electrophoresing

1. Place cover on gel box.

2. Check to insure that the power supply is off.

3. Connect the red cord to the red terminal on the power supply and the red (anode)
terminal of the gel box. In the same way connect the black cord to the black
terminal on the power supply and the black (cathode) terminal on the gel box.

4. Set the power supply switch to 12 volts.

5. Turn the power supply on.

6. Run the electrophoresis until the bromophenol dye (purple band) of the loading dye
mixture is one centimeter from the end of the gel.

7. Turn the power supply off.
8. Disconnect red and black power cords.

9. Remove the chamber cover and remove the gel tray.

154

PART E: Staining and destaining

1. Carefully slide the gel from the gel tray onto a staining tray. (Styrofoam meat trays
work well for this). The gel can be wrapped in Saran and refrigerated overnight
if needed.

2. Cover the gel with 0.025% methylene blue stain.

3. Allow to stain for 15 minutes.

4. Pour the stain back into stock solution container.

5. Cover the gel with tap water. Allow to dcstain for 2 minutes. Pour water off. Add
clean tap water. Destain for 2 more minutes. Continue this process until DNA

bands become visible. Destaining too long will result in loss of bands.

6. Wrap in Saran and store in the refrigerator overnight. This will further develop the
bands.

7. View on white light table, if available.
8. Measure the distance of the DNA bands from the point of origin.
DATA:

Draw a sketch of your gel showing the DNA bands. Be sure to properly label the gel.

155

QUESTIONS:
1. Explain why some DNA fiagments move farther than others.

2. List several factors which afi‘ect the distance a molecule will move in gel electrophoresis.

TEACHER’S GUIDE:
MATERIALS:

Lambda DNA - this can be ordered from Sigma Chemical Company or through
MSU Biochemistry Stores

Loading Dye - 0.1% bromophenol blue in 50% glycerol

OR
methylene blue stain - 0.025 g diluted in 100 mL of distilled water. A stock solution of
0.1% methylene blue is handy to have in any biology classroom. This is a vital stain and
can be used for many purposes. A serial dilution of this will produce the 0.025% stain
needed for this experiment.
DISPOSAL:
Gels can be disposed of in a landfill. Buffer can be re-used for future electrophoresis
REFERENCES:

Electrophoresis 2: DNA Separation in Agarose Gels, Kemtec Educational Corporation,
1992.

Rost, Carolyn. (1990). Lab Manual. Michigan State University. East Lansing, Michigan.

Revised by Karen Pawloski

BIBLIOGRAPHY

WORKS CITED

Anderson, J.M., Oxidation-Reduction in Blood Analysis: Demonstrating the Reaction in a
Breathalyzer, 1990, .L_Chom._Ed, 67:263.

Beck, Isabel. "Reading and Reasoning." Ibo Reading Rasher. May 1989. V42 N9 676-
682.

Burke, B.A., Measuring Breath Alcohol Concentrations, JCST, 12/91- 1/92:
176-7.

Clifton Meloan, Richard James, Richard Saferstein. (1990). Criminalistics: An Introduction
In Eomnsic Sbiancb Lab Manual. New Jersey. Prentice Hall.

Electrophoresis 2: DNA Separation in Agarose Gels, Kemtec Educational Corporation,
1992.

Forbush, Chris. (1993) Research Project. Michigan State University. East Lansing,
Michigan.

LaBlanca, D.A., The Chemical Basis of the Breathalyzer“. A Critical Analysis, 1990,
J. Chem. Ed., 67L 259-61.

Lozauskas, Dorothy and John Barell. "Reflective Reading." The Science Teacher.
NOV.1992. V59 N8.

Miller, LS. and A.M. Brown. (1990). Criminal Exidence Laboratory Manual An
Introduction to the Crime Laboratory Second Edition. Ohio. Anderson
Publishing Company.

Nichols, Sue. "The Science of Sleuthing." Cit): Limits. Aug. 1995 21-25.

Pawloski, Karen. (1996). Forensic Science in the High School Classroom. Michigan State
University. East Lansing, Michigan.

Rost, Carolyn. (1990). Lab Manual. Michigan State University. East Lansing, Michigan.

156

157

Saferstein, Richard. (1990). Criminalistics; An Introduction to Eorcnsic Science 41h
Edition. New Jersey. Prentice Hall.

Schlitz, Gary. (1994). Forensic Laboratory Science and Detectiye Writing. Illinois. Flinn

Scientific, Inc.
Science Kit and Boreal Laboratories. "DNA Fingerprinting." New York.

Siegel, Jay. (1993). Eorensio Science Lab Manual. Michigan State University. East
Lansing, Michigan.

The Alcohol Breathalyzer Test: A Laboratory Simulation, 1989, The Chemistry of Life,
Woodrow Wilson Workshop.

The Alcohol Breathalyzer Test: A Laboratory Simulation, 1992, Cell Molecular Biology,
Towsley Foundation Workshop, Michigan State University.

’IheChemistryofKeeoingClean, IeachersGuide. AModuleinHighSchoolScience.
(1989). Michigan State University. Lessons 18-22.

Tirnmer, W.C., An Experiment in Forensic Chemistry: The Breathalyzer, 1986, J. Chem.
Ed., 63: 897-8.

Tzimopoulos, Nicholas D., H.C. Metcalfe, J. Williams, Joseph Castka. (1990). Modern
Chemistry Laboratory Experiments. Texas. Holt, Rinehart and Winston, Inc.

United States. The National Commission on Excellence. A Nation at Risk; Ibe
lmoeratiye for Educational Reform. April 1983.

Vander, A., James Sherman, Dorothy Luciano ( 1985). Human Ehysiology: Ihe
Mechanisms of Body Eunction. McGraw Hill, Inc.

Washbum, Sherwood 1.; The evolution of man. Sci. Amer. September". 194 - 208: 1978.

Yager, Robert and John Penick. "Resolving the Crisis in Science Education: Understanding
Before Resolution." Science Education. Jan. 1987. 49-55.

"111111111111111111111115