THESIS

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thesis entitled

COMPARISON OF HIGH SCHOOL PHYSICS STUDENTS'
ACHIEVEMENT IN A TRADITIONAL CLASSROOM TO
STUDENTS IN A DISCOVERY BASED CLASSROOM

presented by

Jeffery John Chorny

has been accepted towards fulfillment
of the requirements for

M.S. degree in Physical Science

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Date July 16, 1998

 

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1m WW“

COMPARISON OF HIGH SCHOOL PHYSICS STUDENTS’ ACHIEVEMENT IN
A TRADITIONAL CLASSROOM TO STUDENTS IN A DISCOVERY BASED
CLASSROOM

By

Jeffery John Chomy

A THESIS

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

MASTER OF SCIENCE

Division of Science and Mathematics Education
College of Natural Science

1 998

ABSTRACT

COMPARISON OF HIGH SCHOOL PHYSICS STUDENTS’ ACHIEVEMENT IN
A TRADITIONAL CLASSROOM TO STUDENTS IN A DISCOVERY BASED
CLASSROOM

By

Jeffery John Chomy

The purpose of this study is to compare student achievement in a high school
physics unit on pressure using two different teaching methods. The control
group was taught in a traditional teaching environment where students heard
teacher lecture, saw teacher demonstrations, and were assigned physics
problems from the textbook in an effort to learn the content. The test group
received very little direct teacher instruction. Rather, students worked in small
groups and were given investigative activities to construct their knowledge of the
objectives. The test group recorded their Ieaming in research lab books and the
teacher acted solely as a facilitator. Both groups were expected to master the
same objectives and were given identical tests and quizzes. When comparing
assessments, this study did not reveal extreme differences between the groups,
but some key points can be noted when the data is analyzed. When
assessments were analyzed more thoroughly, the test group showed a little more
thorough understanding of the concepts and were able to apply these concepts

in new situations.

ACKNOWLEDGMENTS

To my wife who had
the patience and
proofreading skills
to assist me with this.
I would not have been able to
complete this without her.
Thanks.

iii

TABLE OF CONTENTS

 

LIST OF TABLES

 

LIST OF FIGURES

 

INTRODUCTION

 

”‘1 Statement of Rationale

 

1 Literature Review

 

\Demographics

 

1. IMPLEMENTATION OF UNIT

 

Objectives

 

EVALUATION

 

. CONCLUSION
APPENDIX A (Control Groups Activities)

 

Appendix A1 (Density Lab)

 

Appendix A2 (Archimedes’s Principle)
APPENDIX B (Test groups Investigations)

 

Appendix Bl (Density)

 

Appendix 82 (Pressure)

 

Appendix BS (Fluid Pressure)

 

Appendix B4 (Archimedes’s Principle)

 

Appendix BS (Bemoulli’s Principle)

APPENDIX C (Assessments)
Appendix Cl (Concept Test)

 

 

Appendix 02 (Quiz 1)

 

Appendix 03 (Problem Test)

 

Appendix C4 (Post Test)
APPENDIX D (DEMONSTRATIONS)

 

BIBLIOGRAPHY

 

3O
33

37
38
4O
42

46
47
48
49

50
53

TABLE 1:
TABLE 2:
TABLE 3:
TABLE 4:
TABLE 5':
TABLE 6:

LIST OF TABLES

 

 

Statistics from the pretest 18
Statistics from the quiz 19
Statistics from concept test after covering objectives-m» 19

 

 

 

Statistics from the problem test 20
Statistics from the post test 21
Students’ opinions 26

LIST OF FIGURES

FIGURE 1: Missed questions by concepts. (Concept Test) 24

 

 

FIGURE 2: Missed problems by concepts. (Problem Test) 24

FIGURE 3: Missed questions and problems by concepts. (Post Test)--- 25

vi

INTRODUCTION

STATEMENT OF PROBLEM AND RATIONALE FOR STUDY

l have been teaching physics for five years and have attended several hours of
workshops and seminars on how we as educators should be using inquiry based
Ieaming. I wanted to know if there is a difference in student comprehension
when comparing cooperative discovery based Ieaming to traditional teaching
methods. I decided to test this notion in an introductory physics course on
pressure. Before the study, my classroom was set up as an interactive lecture. I
used demonstrations and laboratories to enhance the objectives. l involved my
students in lectures and/or demonstrations. I used real life scenarios because I

believed that if one can make the concept relevant, students remember it.

I wanted to know if the technique of, cooperative discovery gased Jeaming is
indeedfflegtwe The questions I asked myself were: Should school districts
make drastic changes from traditional to discovery Ieaming? What kind of
changes should be made? How will this affect the students comprehension? In
a comparative study which group, traditional or inquiry based, will actually Ieam
and apply the objectives? Is cooperative Ieaming an effective technique for
Ieaming? Because I wanted these questions answered, I developed and

executed a study of inquiry based Ieaming.

Inquiry based Ieaming requires active students and their use of higher order
thinking‘skills. Michigan Essential Goals and Objectives for Sea}; Education,
as well as my local district’s goals, stress higher order thinking skills. Students in

the inquiry based test group not only had to comprehend the objectives, but also

plan, judge, examine, construct, set up and argue their Ieaming with group
members. Students in the test group had to analyze, evaluate, and synthesize
the new information and apply this knowledge to real life situations. Students in
the control group simply were taught the objective on the knowledge and

comprehensive levels of understanding.

I chose to base this study on the unit on pressure because it involves some
exciting labs and demonstrations and typically students have several
misconceptions on this topic. Therefore, I thought a quality comparison could be
made between the control and test group. In the test group, students explore
their misconceptions using hands-on activities. The best discovery is when a
student figures out his or her own misconception and makes the correction. In
my previous experience, I found that many times students go back to their
original misconception despite intensive instruction. My goal was for students to
discover their misconceptions about pressure, make the corrections in their

scientific knowledge, and retain this information.

To construct the test group activities many materials were used and adapted.

The physics textbook W95 by Joseph Boyle was
the source for the objectives in the study. Students in the control group strictly
used the textbook Ehysics by Douglas C. Giancoli. Students in the test group

did activities designed by the researcher who based them on the sources

W by AI Guenther and
BMW by James Cunningham

and Norman Herr. Several activity ideas were derived from the these textbooks.

 

In designing the investigations for the comparative study, several hours were
spent researching , designing, and testing the activities using Michigan State
University’s facilities. Several hands on activities were gathered and modified.

These include:

Can Crusher Balloon in a Vacuum
Marshmallow in a Vacuum Siphons

Measuring Densities Pressure Versus Depth
Bemoulli’s Principle Garbage Bag

See Appendix B and D for full description of activities
Additional work developing questions for assessment and evaluation was also
done at Michigan State during the summer of 1997. These activities will be

explained in more detail in the Implementation section.

LITERATURE REVIEW

Based on my experience, business and industry seem to condemn public
schools for producing students lacking required skills. They need students who
can think on their own yet can work with others effectively in a group. The
discovery Ieaming approach of teaching is possibly a step toward meeting their

needs. Discovery Ieaming' Is an example of a constructIVIst approach to

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Ieaming. Constructivism IS a learrI-by-doing approach. “The theory' Is that the
m}; we acquire on our own is easier to remember than the knowledge we
get from others" (Friedman, 1997). Constructivism has its roots in the humanistic
philosophy of education which centers on human interests and values
(Slavin,1988). In constructivism, the teacher guides students on their
educational journey. This type of pedagogy used in this study, is a cooperative
discovery approach (Miller, 1990). The famous Swiss psychologist Jean Piaget

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was theleader of the constructivist movement. He said, “T he basic idea of

3

constructivism is that knowledge must be constructed by the learner; it cannot be

supplied by the teacher” (Holzer,1997).

Many other historical philosophers had an impact on education that support the

discovery approach to teaching. For example, Jean Jacques Rousseau believed

 

 

in student centered curriculum, which ultimately results In deepened Student

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understandlng (Lawrence 1970). John Dewey also called for more active
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student involvement' In Ieaming. He supported problem or thematic based
Ieaming where the content was not selected by adults alone (Travers and
Rebore, 1987). Later, Jerome Bruner echoed Dewey’s thoughts and further said
that subject matter could be changed to fit the child's individual needs by making

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their own IanIry (19.66)

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The discovery Ieaming approach involves the following process:

-Problem posing (an hypothesis is not true or false; more of an open
ended question)

-Generating observations

-Confirminngisconfirrning Hypothesis

Reaffirming Hypotheses

-Explaining or proving a Hypothesis

(Bishay, 1998)

The above steps were the bases of the format that I used to develop
lessons/investigations for the test group as will be discussed in the

Implementation section.

Current research reported in Caine and Caine on how the human brain operates
supports the use of discovery based Ieaming in classrooms. The brain can

detect patterns and make approximations, remember, self-correct and Ieam from

experience. Many studies show that multiple complex and concrete experiences
are essential for meaningful Ieaming and teaching. The traditional model of
education may be inappropriate because skills and attributes students need tend
not to be addressed, and this model fails to take advantage of the brain’s
capacity to Ieam. To be successful learners and employees, students have to
be problem solvers, decision makers, adept negotiators, and thinkers who are at
home with open-endedness, flexibility and resourcefulness. ”For any skill to be
deeply mastered, students must have substantial opportunity to create their own

meanings and organize skills in their brains in their own ways” (Caine and Caine,

1994)

Slywester writes that memory networks are not engaged unless the students are
emotionally involved (1995). Much of what is taught in school tends to be
perceived by students as random obscure facts. Our task as educators is to help
students to find relationships between the somewhat random, often “trivial" facts
of everyday and school life and help them create memory networks that solidify
those relationships. The best school vehicle for building these relationships is
through conversations, debates, role playing, simulations, songs, games, films,
and novels (Sylwester, 1995). This research on how the brain learns,
remembers and forgets supports the use of cooperative discovery as a mode of
Ieaming, because in this approach students engage in conversation, debates,

and are emotionally involved in their Ieaming.

In reviewing this approach to Ieaming and teaching, I needed to determine if we
were just trying something new for the sake of change. I sought out and
evaluated sources that contradicted the support of cooperative discovery

Ieaming. Geiker (1997), a practicing physicist, defended the

5

lecture/demonstration technique of teaching. He believes that students have too
many misconceptions in physics. If a teacher does not confront the student’s
misconception through lecture, it will never be corrected (Geilker, 1997).

Another article (Birk, 1996) states that the key to lecture seems to be interactive,
where the teacher still does most of the talking, but engages students with
questioning and storytelling. Birk states that this method is particularly effective
in teaching abstract subjects like higher math or physics. Birk restates that
teachers still talk 70% of class time and students listen. She thinks there are
trade-offs between lecture style and discovery Ieaming: “Group Ieaming does
foster certain skills, but what does group Ieaming not teach? And are those skills

important?” (Birk, 1996).

Businesses say they want employees who can work well in cooperative teams.
Education has long heralded the positive benefits of cooperative Ieaming, but
there are mixed opinions about whether cooperative Ieaming is useful and
productive in the work place. For example, Bryant, a writer from the New York
Times states: “Cooperative Ieaming and working sounds great but it’s often
misused or overhyped. Learning takes work, and cooperative Ieaming takes the
work right out of Ieaming. Businesses talk about teamwork, but do not actually
use it in their job in any meaningful way. Some say that teamwork is a feel-good
approach that gets in the way of actually accomplishing something” (Bryant,

1998)

Discovery Ieaming has not taken a strong hold in education for many reasons.
One reason is that the processes and outcomes of inquiry Ieaming are not well
documented and understood. Also, do students really Ieam more effectively

through discovery Ieaming than didactic teaching? Lastly, there is no clear

6

consensus on the goals for discovery Ieaming (Cohen, 1988). Critics worry that
children take longer to 'construct’ their own meaning and may come to incorrect
conclusions without more guidance (Friedman, 1997). The basic question is: Is
discovery based Ieaming worth the extra time compared to more traditional
approaches? Several studies suggest that it is. For example, of 67 studies
pertaining to discovery Ieaming verses traditional Ieaming, 61% showed greater
achievement in a discovery based class. 37% showed no difference in

achievement (Bans-Sanders, 1997).

In every source reviewed, the main goal of discovery based Ieaming was to have
students develop higher order thinking skills. This was one of the main reasons I
wanted to take the extra time to test a cooperative discovery Ieaming approach.

I think that students will gain the necessary skills to be successful in the real
world from this approach. I am, however, skeptical about the extra time needed
to teach using this approach. Is it most efficient in Ieaming physics content and

correcting students' misconceptions?

DEMOGRAPHICS

The school in which this study took place was a suburban high school with a
student body of approximately 960 students. Of the 960, about 90% are
Caucasian. The remaining 10% were a variety of Indian, Afro-American, and
Asian. Most of the students came from a middle to upper class background. Of
the 91 students in the control and test group, 37 were juniors and the 54 were
seniors. Most students did not need this physics class, but took it because it
looks good on a transcript or they were looking for one more science credit. Of

the 91, there were 36 female and 55 male students.

7

All of the students in the study plan on attending college and ultimately receiving
a bachelor’s degree. The majority of students have not chosen their careers.
There are approximately four students who plan to pursue engineering. The

rest plan on going into fields related to medicine, or are undecided.

The Physics course is an elective class and few of the students were highly
motivated to Ieam the subject. By my estimate, there were approximately 26
students throughout the test and control group who were actually interested in
physics. The remaining students did show an interest in different concepts
throughout the year. This indifferent attitude makes teaching this course
challenging. The course is not required for graduation from high school, but is

important for students going to college in science or engineering.

There were five physics class sessions involved in the study, each approximately
55 minutes. All of the students had completed algebra with a grade of B or
better. Many students were taking pre-calculus or calculus. Most students were
hard working, serious students, and discipline was not a problem. Although most
were not intrinsically interested in Ieaming physics, they were very grade
conscious. In my view, this provided for an ideal climate to test the academically

inclined students in order to conclude what teaching strategy works best.

Following is the break down of my schedule and which classes were control

group and test group for each day:

Lecture/Demonstration Control Group

Hours Number of students
1st hour - 8:00 to 9:05 19
2nd hour - 9:10 to 10:00 13
3rd hour - 10:05 to 10:55 Conference Period
4th hour - 11:00 to 11:55 24

Discovery Test Group

5th hour - 12:35 to 1:30 13
6th hour - 1:35 to 2:30 22

IMPLEMENTATION OF UNIT

The control group did not experience an extreme change in their Ieaming
environment compared to that of my previous classes during the study. This
group was taught under the traditional philosophy that the teacher was the sole
dispenser of knowledge. Teacher led discussions, demonstrations, and “cook
book” type labs done by students were the primary teaching methods. In a
traditional classroom such as this, the teacher states the objective, gives the
information, leads students through some lab activities, and the students

regurgitate information back on a test or quiz.

The second group was my test group. They saw a drastic change in the Ieaming
environment. Students in the test group were required to meet the same
objectives, but were encouraged to construct their own understanding through
hands-on investigations while working in small groups. Students were
sometimes given only the problem and some materials and were instructed to
create their own lab experiment to Ieam the objective. Students had access to
computers, textbooks, and laboratory facility. The teacher acted as a facilitator.
Other times the students were given guided investigations and additional
information on the topic and then tested this concept in small groups. Each
student was required to record in a research book the purpose, procedure, data
of their test, and evaluate each discovery. Following this, students were given
questions pertaining to real life scenarios where they had to apply this newly

acquired knowledge.

The unit was taught right after the first semester exams and took 4.5 weeks to

complete. The students previously had completed a four month study of

10

mechanics. There were 56 students in the control group and 35 students in the
test group. The test group was split up into working groups of two or three.
Every group had an “academic” person as well as a more creative and
“hands-on" type person based on performance in the first semester. Before
implementing the unit, a pre—test (Appendix C1) was administered to all students
to inform the researcher what areas needed work and to provide as a basis for

data analysis.

Following are the five topics and the corresponding objectives taught in this unit.
A brief outline of what was done by the control group and test group is included
with each objective. Lastly, a brief overview of what took place during the lesson

and students' behavior are documented.

Students Under Pressure

1. Density - p = MN

Objective: Distinguish between density, weight density, and specific gravity.
Given an object’s mass and volume, calculate the object’s density, weight

density and specific gravity.

Control Group: Students were given a lecture on density. All terms were
defined and examples were given. There were comparisons of different
densities and how they are important in science. The teacher completed a few
sample problems on the board and then students were assigned problems from
the textbook. The laboratory was a textbook lab (Robinson, 1992) on finding
density of regular and irregular objects (Appendix A1).

11

Test Group: Students were given handouts on the objectives and the
investigation they were to do (Appendix B1). Each group was to Ieam this
objective using textbooks, computers, and the teacher as resources. This group
had to discuss, research, analyze the objective, and then apply this to their lab
investigation. The investigation was to find the density of regular or irregular
solid objects. They needed to devise a plan to solve this problem. The students

had to use a complete scientific format in their research books.

Overview: The students in the control group did not have many questions.
They completed the problems and lab as was done in the past. The test group
wanted all of the answers from the teacher. The students had to rely on each
other to develop the activity and Ieam the objective. When using the computers
as a resource, the students were extremely frustrated because the lntemet was
running slowly and there were six people per computer. In future, computers will

be used on a limited basis.

2. Pressure- P = FIA

Objective: Define pressure, air pressure and calculate the pressure that an
object of known weight exerts on a surface of known area, and then express the

magnitude of the pressure in psi, lb/ft2, N/m2 or Pascal's (Pa).

Control Group: The teacher defined terms and discussed sample problems.
As a group students calculated how much pressure they apply to the floor.
There were two demonstrations on air pressure: 1. A person was placed in a

garbage bag with their head sticking out of the bag and the air was removed;

12

2. By heating a can with a little water at the bottom and tipping it upside down

into cool water, you will see a can get crushed. (Appendix D1 and DZ).

Test Group: The test group was given information about pressure and air
pressure in the form of handouts. The terms were defined to make sure they
understood them. They were also given four investigations to test and evaluate.
The four investigations were: 1. Calculating pressure of someone’s foot on the
floor and making comparison to air pressure; 2. Collapsing a can; 3. Breaking
wood slats using paper, air pressure and a hammer; 4. Students climbed into a
garbage bag with their head sticking out of the bag and used a vacuum cleaner

to remove the air out of the bag (Appendix 82).

Overview: I believe that the test group started to enjoy their freedom of
Ieaming. The students were actually applying some physics to real life
situations. This was exciting for the teacher and students. The test group was
seeing a connection from the objective to the actual investigation. The problem
with the investigations was time. The control group finished this objective in a

day but the test group needed two to three days.

After teaching the first three objectives, the teacher presented three

demonstrations to both groups: 1. Behavior of a marshmallow in a vacuum jar;
2. Behavior of a balloon in a vacuum jar, 3. Boiling water at room temperature.
The control group just saw the demonstration; then we discussed it as a group.
The test group had to explain what happened in each case in their research lab

books (Appendix D4, D5, and 06).

13

3. Fluid Pressure - P = pgh

Objective: Calculate the pressure acting at a depth below the surface of a
liquid with known density. Distinguish between absolute pressure and gauge

pressure, and solve problems involving each type of pressure.

Control Group: They had a lecture on how depth affects pressure. All terms
were defined and sample problems were done using the equation above. The
teacher demonstrated a newly developed apparatus. This apparatus is
described in Appendix D. The water filled tube demonstrates how a balloon
contracts at different depths. The teacher set up the tube where students could
pull a balloon down to different depths and measure the volume change

(Appendix D3).

Test Group: The test group was given information regarding fluid pressure.
The students had to define all relevant terms and then apply them to real life
situations. The students were given four investigations to test and evaluate:

1. Using the new apparatus the students actually measured the volume change
of a balloon as it was pulled down deeper into the tube; 2. Make a siphon and
explain how it works and its uses; 3. The students made a carpenter‘s level to
show how water seeks its own level; 4. The students used a two liter bottle to
show how depth effects pressure. In every investigation, the students were to

use the scientific approach and write in their research lab books. (Appendix B3)

Overview: The control group, in my observation, feels as if they are dragging
their feet. They would like to move on to another topic. The test group needs

more time to investigate. The lab gets wet just about every day. Some students

14

in this group wonder if they are actually Ieaming the objectives. The test group is

very concerned about their grade.
4. Archimedes’s Principle - Buoyancy Force (FB = m. 9)

Objective: State Archimedes’s principle and use this principle to solve and

apply to related buoyancy problems.

Control Group: This group was presented with a definition on Archimedes’s
principle. There were discussions on how this applies in everyday life. Sample
problems were done on the board and students were assigned problems out of
the textbook. There was one “cook book” style lab from a lab text (Robinson,

1992) to demonstrate Archimedes's principle (Appendix A2).

Test Group: They were given background information on buoyancy and told to
define each term and make sure they understood these terms. The students
were given three investigations: 1. To make a boat out of aluminum foil. This
was to demonstrate that water has to be displaced before things can float;

2. This investigation was to go one step further by calculating the buoyancy
force of different objects; 3. To make a fresh egg float and explain why it did.
Each investigation required observations, procedures, and evaluations

(Appendix B4).
Overview: Investigations related to Archimedes’s principle did not go well for

either group. The boats they made did not float. I had to change the lab slightly

to make it more meaningful. The biggest difficulty in teaching this concept was

15

for them to think on their own. The students wanted the teacher to give them the

answer on how they should measure how much water was displaced.
5. Bemoulli’s Principle - (no equations)
Objective: Be able to state Bemoulli’s principle and apply it to everyday life.

Control Group: I as the teacher defined the terms and conducted two
demonstrations. In one demonstration, two pieces of paper are pushed together
when you blow air between them (Appendix D7). The other demonstration was
drawing water up into a straw by blowing air over the top of the straw. The
subsequent demonstrations led to a discussion on how airplanes fly. The
students had some concept questions they had to apply pertaining to this

principle.

Test Group: The students were given handouts on Bemoulli’s principle. They
were required to go through the material as a group and investigate the pressure
changes related to fluid motion. The students had access to computers,
textbooks, and the teacher. The students then had three investigations that they
were to write up completely in their lab books: 1. Two ping pong balls get
pushed together by blowing air between them; 2. Make a manometer by drawing
water up into a straw and measuring the height; 3. Make a piece of paper go up
by blowing over the top of it. These investigations really did not take long and
required few- calculations. The students simply recorded their observations

(Appendix B5).

16

Overview: From the assessments and my observation, the control group did
not understand the demonstrations. They did not really understand the
objective. The test group again ran out of time to complete the required
investigations. I had to cut them short. The investigation in the test group went
very well. Based on the assessments and my observations, these students

actually understood Bemoulli’s principle and could apply it to a real life situation.

17

EVALUATION

The pretest (Appendix C1) given at the beginning of the unit consisted of 24 real
life questions pertaining to all of the objectives. This was used as a gauge of
what the students already knew about pressure. It was also a basis for
comparison of the data collected between the control and test group. Each
question on the pretest was graded on a three point scale: one point for the
correct answer; one point for the correct explanation, and the last point was a
judgment call on my part. The results of the pretest show that the test group had
more background knowledge about the unit. The t-test shows that the calculated
number is greater than the critical number. This indicates that there is a definite

difference between the two groups normal distribution curve (Table 1).

Table1: Statistics from the Pretest.
' 3 Control Group . Test Group
Number of Students I 56 T 35

 

 

 

 

 

 

 

Average on Test l 34.66% : 41.23%
Standard Deviation l 11.96% g 12.23%
,_._ T - Test
Calculated Score 9 f Critical Score
2.483 g 2.021

 

 

The quiz (Appendix CZ) was given after the first objective was taught. The
questions were generated from previous problems and labs. All questions had
equal value and partial credit was given for stating the right equation or process.
This was determined by me. There were two laboratory questions where the
students had to measure and calculate different densities. My observation of the

lab portion of the quiz was that the test group completed the task much more

18

quickly. The results of the quiz do not show significant differences in the

average or the t-test (Table 2).

 

Table 2: Statistics from the Quiz.
1 l Control Group : Test Group

 

 

 

 

 

 

 

Number of Students 56 35
Average on Test j 85.07% 88.37%
Standard Deviation 10.34% 12.76%
l T - Test 1
Calculated Score ' Critical Score
1.27 2.021

 

 

The concept test (Appendix C1 ), consisting of the same questions as the pretest,
was administered at the end of the unit. The same three point grading scale
discussed earlier was used to evaluate this test. The results of the concept test
do not show significant differences in the average or the t-test. In fact, both

groups are at the same level at the end of the unit (Table 3).

Table 3: Statistics from the Concept Test.
l Control Group ‘ Test Group

 

 

 

 

 

 

 

Number of Students f 56 35
Average on Test l 72.27% 77.17%
Standard Deviation lI 11.31% 5 10.98%
E T - Test 1
Calculated Score j Critical Score
2.022 = ' 2.021

 

l9

The problem test (Appendix C3) had 8 questions that required the students to
apply an equation to a problem. All questions were problems that both groups
completed in class. The students could not have prior knowledge of the
equations so I did not give a pretest on this. Every question was of equal value
and there was partial credit given for students using the right process. This was
a judgment call on my part. The results of the problem test do not show a drastic
change in the average but the t-test does show that the students in the test

group as a whole had a better understanding of the problems.

Table 4: Statistics from the Problem Test.
Control Group . Test Group

 

 

 

 

 

 

 

 

Number of Students 3 56 35
Average on Test , 76.20% 80.74%
:Standard Deviation 1 10.91% 8.61%
_ ,_.- -- ; T - Test
__ Calculated Score ' Critical Score
_ 2.396 * 2.021

 

The post test (Appendix C4) was given three months after the unit was
completed. The students were not aware that they would be given this test. The
questions were generated from the problem test and pretest. I took what I
thought were important questions related to each objective. Each question was
worth 3 points and the same scoring was used as in the pretest. The result show
that the students in the test group did have a higher average. The t-test also
indicates that the normal distribution curve was not overlapping. This shows that
more of the students in the test group had a better understanding of the unit after

three months (Table 5).

20

Table 5: Statistics from the Post Test.
1 Control Group Test Group

 

 

 

 

 

 

 

 

Number of Students ~ 56 35
Average on Test 1 52.50% 59.94%
lStandard Deviation ,1 14.85% 12.82%
T - Test 4
Calculated Score ? Critical Score
2.501 ; 2.021

 

When comparing the pretest data (Table 1) between the control group and test
group, no striking differences are found. In the pretest, there was a 7%
difference in the average score, with the test group scoring higher. The test
group continued to score higher on all assessments throughout the teaching of
the unit. On the quiz, the test group scored 3.3% higher at 88.37% (Table 2).
On the concept test, the test group scored 5.1% higher at 77.17% (Table 3). On
the problem test they scored 4.54% higher at 80.74% (Table 4). This indicates
that overall the test group did slightly better than the control group in all areas.

However, one must note that the test group had scored higher on the pretest.

One important difference noticed in the scores is the standard deviation.
Comparing all the standard deviations on all four tables, one can see that the
test group’s standard deviation went down compared to that of the pretest.
There were definite changes in Table 3 and Table 4. The test group had a lower
standard deviation by 1 or 2 percentage points. This is not very significant but
the improvement suggests that the cooperative Ieaming groups put everyone
closer to the average. I can attribute the drop to students working in cooperative

groups on the investigations.

21

After completing the unit on pressure, I administered a post test. Once again the
test group scored better, 7.44 % higher, with an average of 59.94% (Table 5).
The test group also had a lower standard deviation by 2 points at 12.82. This
suggested that the test group retained more, and after three months, could
perform better on this test than the control group. It would be interesting to test

these same students one year later to see what the test scores would indicate.

The averages and standard deviation of the assessments do show some
interesting data. In the Host score, I see slightly different results. The t-test
shows the overlapping of the normal distribution curve. The critical score is from
a table. If the calculated score is above the critical score, I can conclude that
there is a definite change between the two distribution curves from each group.
The pretest, problem test and post test showed the strongest change. They are
approximately 0.3 to 0.5 points above the critical score. Looking at Table 1, I
note that the test group had much more prior knowledge and they did sustain
this throughout the unit. The concept test, on the other hand, did not show a
drastic change between groups. This suggests that the control and test groups
were not all that different right after the unit. In comparing Table 1 and Table 5,
the t-test indicates that the test group did retain the material and performed

better as a group.

The data indicates that the test group performed better on the various
assessment instruments. I also analyzed the data by topics. Each question on
the tests could be broken into five topics correlated to the five objectives. The
concept, post and problem test questions were sorted into these five topics. I
went through each test and tallied each question that 15% or more of the

students missed. Figure 1 (Concept Test) shows that the test group knew the

22

topics as well as or better than the control group. Data for Figure 2 (Problem
Test) was derived the same way, and again the test group did not miss as many
of the topics. In the post test, the test group continued to score better (Figure 3).
This suggests more of the students in the test group had a deeper understanding
of the concepts because they had more time to analyze, think for themselves,

devise a hypothesis and test.

The successful investigations correlate with the data in the Figures. Density,
pressure, fluid pressure, and Bemoulli’s principle were the investigations for
which students showed improvement for the test group. When Ieaming these
four topics, the test group had time to analyze the investigations. The
cooperative Ieaming groups were a benefit in this type of Ieaming. The concepts
were reinforced with the investigations as well as the cooperative Ieaming
groups. By my observation, the students saw a connection between the concept
and real life situations. The area of study that did not show a change between
the test and control group was Archimedes’s principle. This objective was the

most difficult for all of the students and the data reflects this.

23

Figure 1: Student’s missed questions by topics in the Concept Test.

Number of Questions Missed

 

Concept Test
Number of missed Questions

   

 

 

 

. 311:? -
P essure Fluid Pressure Archimedes's Bemoulli's

Concepts

Control Group El Test Group

Figure2: Student’s missed problems by topics in the Problem Test.

Number of Questions Missed

3.0

2.5%

2.01

Density

    

Problem Test
Number of missed Questions

  

  

 

"mil LIDI I 1 "
Pressure FIui Pressur Archimedes

Concepts
Control Group 3 Test Group

24

's Bernoulli's

Figure 3: Student’s missed questions by topics in the Post Test.

Post Test
Number of missed Questions

51

Number of Missed Questions

  

 

   

Density

Concepts
Control Group : Test Group

The students in the test group were very excited and interested about the new
discovery approach to Ieaming. This excitement did taper off near the end of the
fourth week. According to the survey that I conducted informally, most students
in the test group enjoyed the hands-on approach (Table 6). The majority of the
students did not enjoy writing every day in their lab books. This is typical of most
students. Some students did enjoy the freedom to Ieam the objective as a group
and others did not. Most students wanted the teacher to lecture to them.
Typically, these were students who were very conscientious and very concerned
about an "A" grade. The two or three students that did not like the discovery
approach did not do well. All students Ieam differently, so several teaching
techniques should be used. By looking at some of the students’ comments, one
can see that some students did not like being forced into higher order of thinking.

Below are some typical responses from the test group:

25

“Are we Ieaming anything?”

“When can you go back to lecture?"

“T his is the way classrooms should be run.”
“I dread going to your class everyday."

“I love playing in the water everyday.”

“I wish we could just investigate and not write in our lab books.”

“Do we have to go back to lecture?”

Table 6: Students' Opinions.

 

 

 

 

 

Question Asked I Yes No
:Liked the Investigations I 33 2
lLiked the writing 1 4 31
Liked the independence 8 27
iLecture back again . 27 8

 

 

26

CONCLUSION

Organizing and executing the discovery approach to teaching was a difficult task
to accomplish. The lessons, based on investigations, were very time consuming
to create, set up and monitor. It was also difficult to act as a facilitator, especially
for students who begged for answers. That said, the hands-on approach and
higher order thinking skills used in Ieaming the concepts went well. The time
constraint for the test group was the biggest drawback. The control group would
have taken about two and a half weeks to work through the objectives, but the
test group required much more time. Questions for an instructor are: Do I have
the time to cover all required concepts using a discovery approach? What is
most important for the students to learn, content or process? I believe a
combination of discovery based Ieaming and traditional based lecture is the best
form of teaching physics. I agree with critics who say discovery Ieaming takes
too long for students to construct meaning and that incorrect conclusions may be
made without more guidance. Therefore, I believe that interactive lecture, 1
several hands-on discovery lab experiments, and the use of cooperative groups
is the most efficient way to teach physics. Every student learns differently, so
using the above combination of approaches should help more students
understand. I believe that when a student comes to the correct conclusion on
his or her own that the student’s understanding is much deeper. However,
students do not always make these connections on their own. I believe the use
of investigative hands-on laboratories helps students to Ieam, retain, and apply
the concepts better, and I intend to change my labs to be more investigative. I
think using cooperative groups is an effective teaching technique and I intend to
use this more often in my class. The use of computers as a resource is not

feasible until our school's computer system is changed to handle a larger

27

number of students. I will be using this new unit in all my classes next year
because I believe that the control group missed out on some very important
concepts on pressure. They also missed out on Ieaming valuable skills such as
working with others in a group and higher order thinking. The answer to the
question, “Should school districts change from traditional to discovery leaming?”,
is in my opinion, not exclusively. Both approaches have benefits, and a teacher

should pick and choose what aspects are most effective for students for a given

topic.

28

APPENDICES

29

 

Name

APPENDIX A1

Period Date

 

Chapter 19: Liquids

 

Displacement and Density

 

45

Eureka!

 

 

 

 

 

 

 

Find the nurss ml

each canister

Observe rise in
water level

Purpose
To explore the displacement method of finding volumes of irregularly shaped
objects and to compare their masses with their volumes.

Required Equipment/Supplies

two 35-min film canisters (prepared by the teacher): one which is filled with
lead shot, and the other with a bolt just large enough to cause the
canister to sink when placed in water

tripleoheam balance

string

graduated cylinder

water

masking tape

5 steel bolts of different size

irregularly shaped piece of scrap iron

IOOO-mL beaker

 

Discussion

The volume of a block is easy to compute. Simply measure its length, width.
and height. Then multiply length times width times height. But how would
you go about computing the volume of an irregularly shaped object such as
a bolt or rock? One way is by the displacement method. Subrnerge the object
in “titer. and measure the volume of water displaced, or moved elsewhere. This
mlume is also the volume of the object. 00 two steps further and (I) measure
the mass of the object; (2) divide the mass by the volume The result is an
important property of the object—its density.

PART A
Procedure

Step 1: Your teacher has prepared two film canisters for you. Each canister
should have a piece of string attached to it. Use a triple-beam balance to find
the mass of each one.

mass of lighter canister

 

mass of heavier canister

 

Step 2: Place a strip of masking tape vertically at the water level of a
graduated cylinder about 213 full of water. Mark the water level on the tape.
Submerge the lighter canister in the water. as shown in Figure A. Observe the
rise in water level. Mark the new water level on the tape Remove the canister.

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30

 

Predict rise in

Observe rise in

APPENDIX A1 (CONT. )

Step 3: Predict what you think the rise in the water level for the heavier
canister will be when it is submerged. Do you think it will be less than. the
same as. or greater than the rise in water level for the lighter canister?

 

prediction;

Step 4: Test your prediction by submerging the heavier canister. Write down
your findings.

 

findings:

Analysis

I. How do the amounts of water displaced by each canister compare?
Since the use in water level is the same for each canister. they must each

 

displace the same amount of water.

 

 

2. Does the amount of water displaced by a submerged canister depend
on the mass of the canister? On the volume of the canister?

The amount of water displaced by a submerged canister depends on its

 

volume but not on its mass.

 

Measure mass and
volume of bolts

Compute ratio of
mass to volume

PART 8
Procedure

Step 5: Measure the mass and volume of 5 different sized bolts using the
displacement method. Record your data in Data Table A.

 

 

 

 

 

 

 

 

BOLT MASS VOLUME .......
get m w M
l
2
3
4
I_—____.
5

 

 

 

 

 

 

Step 6: For each bolt divide its mass by its volume. and enter the results
in the last column of Data Table A.

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Appendix A1 (Cont.)

Name Period Date

 

Analysis

3. How do the ratios of mass to tolume compare for each of the bolts?
All the bolts should have about the same ratio at mass to volume

 

 

4. Would you expect the ratio of mass to volume to be the same for
bolts of different metals?

Bolts ol dullerent metals would have different ratios of mass to volume

 

 

5. What name is given to the ratio of mass to volume? (Fill this name in
at the top of the last column in Data Table A.)

The ratio ol mass to volume is the density.

 

 

PART C
Going Further

Pretend that _\ou are living in ancient Greece during the time of Archimedes.

The king has commissioned a new gold crown to be made of pure gold. The

king is \torried that the goldsmith may have cheated him by replacing some

of the gold with less precious metals. You are asked to devise a way to tell.

without damaging the crown. whether the king was cheated or not.
Unfortunately. your school cannot supply you with an actual gold crown

l'ur this activity. A less valuable piece of scrap iron will simulate the crown.
Write down your procedute and any measurements you make

 

 

 

 

 

 

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32

Name

APPENDIX A2

Period Date

 

 

Chapter 19: Liquids

Archimedes’ Principle and Horation

 

 

flank or Swim

 

Weigh an object in air
and sulmtetgcrl in
water

.lleasure the water
displaced

Purpose

To introduce Archimedes' principle and the principle of flotation.

Required Equipment/Supplies

 

spring scale water
triple-beam balance masking tape
string chunk of wood
rock or hook mass modeling clay
600-mL beaker toy boat
SOO-mL graduated cylinder SO-g mass
clear container 2 IOO-g masses
Discussion

An object submerged in water takes up space and pushes water out of the way.
The water is said to be displaced. lntcrestingly enough. the water that is pushed
out of the way in effect pushes back on the submerged object. For example.
if the object pushes a volume of water with a weight of IO N out of its way.
then the water reacts by pushing back on the object with a force of IO N. We
say that the object is buoyed upward with a force of IO N. In this experiment
you will investigate what determines whether an object sinks or floats in water.

Procedure

Step I: Use a spring scale to determine the weight of an object truck or hook
mass) first in air and then under water. The difference in weights is the buomnt
force. Record the weights and the buoyant force.

weight of object in air

apparent weight of object in water

buoyant force on object

Step 2: Devise an experimental setup to find the tolume of water displaced
by the object. Record the volume of water displaced. Compute the mass and
weight of this water. (Remember. l mL of water has a mass of I g and a weight
of 0.0! N.) '

 

volume of water displaced =

mass of water displaced =

 

weight of water displaced 8

 

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33

 

APPENDIX A2 (Cont .)

1. How does the buoyant knee on the submerged object compare to the
weight of the water displaced?

l’he ouovant lmce should enual the weight ol the water displaced.

 

 

Float a piece of wood Step 3: Find the mass of a piece of wood with a triple-beam balance. and

Data Table A

record the mass in Data Table A.

NOTE: To keep the calculations simple. from here on in this experiment
you will measure and determine masses. without finding the equivalent weights.
Keep in mind. however. that an object floats because of a buoyant force. This
force is due to the weight of the water displaced.

Measure the volume of water displaced when the mod floats Record the
volume and mass of water displaced in Data Table A.

 

 

 

 

 

VOLUME OF MASS OF
OBJECT MASS want WE! motto
( 9) tnLt (9i

WOOD

WOOD Am

50-9 MASS

CLAY BALL

FLOATING CLAY

 

 

 

 

 

 

2. What is the relation between the buoyant force on any floating object
and the weight of the object?

The buoyant lorce on any floating obiect equals the weight of the object.

 

(If it were less. the object would smk: if it were more. the ohiect would rise

 

higher. l

 

 

3. How does the mass of the floating wood compare to the mass of
water displaced?

The mass of the floating ObleCl should equal the mass of water displaced.

 

 

4. How does the buoyant force on the wood compare to the weight of
water displaced?

The buoyant force on the wood. equal to the weight of the wood. also equals

 

the weight ol water displaced. since the masses are equal.

 

 

156 Experiment 46

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APPENDIX A2 (Cont.)

Name Period Date

 

Float wood plus Step 4: Add a SO-g mass to the wood so that the wood displaces more water
50g mass but still floats. Measure the volume of water displaced and calculate its mass.
recording them in Data Table A.

5. How does the combined buoyant foiee on the wood and the SO-g mass
compare to the weight of water displaced?

The combined buoyant lorce. equal to the combined might. also equals the

weight at water displaced. since the masses are equal.

 

illlcasm'e displacement Step 5: Find the mass of a ball of modeling clay. Measure the \olume of water
a] clay it displaces as it sinks to the bottom. Calculate the mass of water displaced.
and record all volumes and masses in Data Table A.

6. How does the mass of water displaced by the clay compare to the
mass of the clay?

The mass of water displaced is less than the mass of the clay.

 

 

 

7. is the buoyant force on the submerged clay greater than. equal to. or
less than its weight in air? Explain.

The buoyant lorce on the submerged clay is less than its weight in air

Otherwise. the clay could not remain submerged.

 

Mold the clay so that Step 6: Retrieve the clay from the bottom. and mold it into a shape that allows
it floats it to float. Sketch or describe this shape.

For more observable
results use dense masses
such as lead weights.

Measure the volume of water displaced by the floating clay. Calculate the
mass of the water. and record in Data Table A

8. Does the clay displace more. less. or the same amount of water when
it floats as it did when it sank?

The clay displaces more water when it floats.

 

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35

APPENDIX A2 (Cont.)

9. Is the buoyant fume on the floating clay greater than. equal to. or less
than its weight in air? '

The buevant force on the floating clay equals its weight in air.

 

 

l0. What can you conclude about the weight of water displaced by a
floating object compared to the weight in air of the object?

The weight of water displaced by any floating object equals the weight in

 

air of the object.

 

Predict new water Step 7: Suppose you are on a ship in a canal luck. If you throw a ton of bricks
level in canal lock overboard into the canal lock. will the water level in the canal lock go up. down.
or stay the same? Write down your answer belore you proceed to Step 8.

 

prediction for water letel in canal lock:

Step 8: Float a toy boat loaded with 'cargo' (such as one or two lOO-g masses)
in a container filled with water deeper than the height of the masses. Mark
and label the water levels on masking tape placed on the container and on
the sides of the boat. Remove the masses from the boat and put them in the
water. Mark and label the new water levels.

ll. What happens to the water level on the side of the boat when you
place the cargo in the water?

The water level on the boat goes down, and the boat rides higher in :::e

 

 

water.

 

l2. if a large freighter is riding high in the water. is it carrying a
relatively light or heavy load of cargo?

A freighter riding high is carrying a relativelv light cargo.

A

 

l3. What happens to the water level in the container when you place the
cargo in the water? Explain why it happens.

It drops. since the cargo displaces less water when it sinks compared to

 

when it is floating.

 

l-l. What will happen to the water level in the canal lock when the bricks
are thrown overboard?

The water level in the canal lock will dron

 

 

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36

APPENDIX B1

Investigations of Density.

1. Distinguish between density which is mass per unit volume, weight density
which is weight per unit volume and specific gravity which is the ratio of the
density of an object to a known density. When given an object’s mass and
volume, calculate the object’s density, weight density and specific gravity.

p = ml V

a. Calculate known density with known mass and volume.
b. Calculate specific gravity and make comparison to density.
0. Figure out density of a cylinder or block vs. an irregular shaped solid.

Assignment from physics textbook: Page 302-304 Q:1,9,11,12 P: 1 - 6

Laboratory: 1. Given two 35 mm canisters, triple beam balance, string,
graduated cylinder, water, bolts, scrap piece of iron and masking tape. Calculate
the densities of the bolts, piece of iron and the two canisters filled with different
amounts of material. 2. Find the density of a block of wood. 3. Compare /
Contrast the density of the bolts in your conclusion

Questions: How do the amounts of water displaced by each canister compare?
Does the amount of water displaced by a submerged canister depend on the
mass of the canister? On the volume of the canister?

Every lab should contain the following: Use ink!

Title:

Purpose:

Procedure: Write in paragraph or number form. Diagrams are expectable.

Data/Calculations: The more detailed the better grade. Significant Digits
and precision of the instruments are very important.
Graph if possible.

Conclusion/Evaluation: Answer the questions. Summarize the lab.

Possible Errors. Did you Ieam anything?
Changes you should have made to the lab.

37

APPENDIX 82

Investigations of Air Pressure.

Concepts to investigate: Definition of pressure, pressure equation, implosions,
atmospheric pressure.

Materials: Balance, meter stick, graph paper, soft drink can, beaker tongs, large
beaker or bucket, packing tape, newspaper, notebook paper, thin wooded slat,
hammer and vacuum cleaner.

Principles and Procedures:

Part 1: How great is atmospheric pressure? Atmospheric pressure at
sea level is 101.3 kPa [14.7 Ib/in2] . Is this a large pressure or a small
pressure? Measure the area of the bottom of your foot. Measure your weight
and calculate the pressure you exert on the floor. Do this same calculation for
several other objects in the room. Make a table of the mass, weight, area,
pressure in Pascal’s, and pressure in Ib/in2. Make sure you have the pressure of
at least four different things. Show all work and calculations. Develop a plan
before getting started with this activity. Show all developments in your lab
manual.

Part 2: The collapsing can. To demonstrate the strength of air pressure.
You need to put a little water at the bottom of a can and boil it. After boiling for
several minutes take the can and put it upside down in a tank of cold water.
Record all observations and explain why this would happened.

Part 3: Put a thin slat of wood such as a paint stirrer on a table so
approximately 20 cm hangs over the edge. Place two sheets of notebook paper
on the slat and press against the table until the paper is as flat as possible.
Strike the overhanging portion of the slat with a hammer. Repeat this procedure
using two pieces of unfolded newspaper and record the area. Calculate the
force exerted upon the paper using the pressure equation. Did the wood break?
Record all observations in your lab book.

Part 4: Put yourself in a garbage bag. Stand so your head sticks out and
suck the air out of the bag using the vacuum cleaner hose. The hose should be
in with the person. If it is a quality garbage bag, every student can experience
the affects of air pressure on our bodies.

38

APPENDIX 32 (cont)

Questions.

1. On the basis of your calculations in part 1, what is the magnitude of
atmospheric pressure at sea level compared to the pressure you exert on two

feet?

2. Under what conditions does the can collapse in Part 2? Explain.

3. Using a diagram of your ears explain why your ears pop when you travel up
and down the mountains.

4. Is it possible to lose your hearing in an airplane if the plane does not become
pressurized? Explain.

5. Why may it be painful to travel into the mountains if you have a head cold?

6. Is the air pressure on the sheet of notebook and newspaper the same?
Explain. ls the force upon them the same? Explain.

7. Did the wood break when placed under the notebook paper? When placed
under the newspaper? Explain.

8. Why do large ships require large sails if air pressure is independent of surface
area?

39

APPENDIX B3

Investigations on Fluid Pressure.

Concepts to investigate: Fluid pressure, pressure differential, siphons, water
levels, pressure, water pressure and depth, pressure and fluid flow.

Materials: Two liter soft drink container, tape, pencil, ruler, pliers, nail, burner,
large pan, tube, beakers.

Principles and Procedures:

Part 1: Measure the volume of a balloon by measuring the radius. Pull
the balloon down with a string. Appendix D3 has further details. Using the
graduated cylinder at the top measure the volume change. Record data in your
lab books.

Part 2: Make a siphon using a tube and beakers. Make sure tube is filled
with water and place tube in both beakers. Raise and lower the beakers. Write
down any observations. Using a 5 m length of tube, determine if water will
siphon between beakers ifthe barrier between them is 2 m high. Try connecting
several beakers in a row with the tubes. What happens? Record all
observations.

Part 3: Carpenter's level: Using a piece of tube about 10 m long, fill the
tube with water so there is about 50 cm of empty tube on each end. Take one
end of the tube to one side of the classroom. Carry the other end with a meter
stick to the opposite end and measure from the floor how high the water level is
in the tube. Determine if the floor is level. Try this again with other parts of the
floor. Make sure both meter sticks are perpendicular to the ground. Record the
heights measured at each end. Are the heights always the same?

Part 4: Pressure versus depth: Place three holes into a two liter bottle,
using a heated nail. Make sure the holes are at different levels and not in line
with each other perpendiculady. Fill the two liter bottle with water making sure
the holes are covered using the pencil or tape. Record the depth of each hole.
Calculate the pressure at each level using the equation P = pgh where the
density of water is 1000 kglm3. Measure the length of water stream when the
straw or tape is removed. Record all calculations and data in a table.

40

APPENDIX 83 (cont)

Questions.

1. Under what conditions, other than entry of air into the tube, will water stop
flowing in the siphon?

2. Using water pressure explain how the water level works in part 3.

3. Explain how a siphon works.

4. Does your data support the equation in part 4? Explain.

5. Describe what would happen to a strong flexible volleyball if you released it
from a submarine at the bottom of the ocean.

6. The Marinas Trench is the deepest known portion of the Earth's surface, with
a maximum depth of 11,034 m. Using the pressure equation determine the
pressure at this depth. How many times greater is the pressure at this depth
than at the surface?

7. What happened to the volume of the balloon as the balloon went to different
depths. Explain.

8. Did the balloon lose any air? Explain.

9. In part 1, what if the tube was filled with a different solution?

41

APPENDIX B4

Investigations on Archimedes’s Principle.

Concepts to investigate: Archimedes’s principle, displacement, determining
buoyant force, buoyancy of different materials, Newton’s third law, weight, and

density.

Materials: Aluminum foil, caulking, beaker, spring balance, graduated cylinder,
metal and wooden weights of equal mass, metal object, salt, and eggs.

Principles and Procedures:

Part 1: Bend a flat piece of aluminum foil so that it will float. Make sure
the boat will displace its weight. Using your constructed measuring device for
displacement, watch what happens to the displacement of water as you
submerge the boat. Make a comparison to the displacement as more is loaded
on the boat until it sinks. Measure the displacement of water in each case.
Record your data in a table for the displaced water. You will have to devise a
plan to measure displacement of water because the boat will not fit into a
graduated cylinder.

Part 2: Using the weights, 3 piece of metal, and a block of wood
measure, calculate, and record the weight of each in air, and in water. Measure
the difference in weight and the weight of the displaced water. Record all of this
in a data table.

Part 3: Place a fresh egg in a beaker full of water. Record any
observations. Slowly stir salt into the beaker and record any and all
observations.

42

APPENDIX 84 (cont)

Questions:

1. Using Archimedes's principle, explain why your boat will sink if placed on its
side.

2. Explain how concrete boats are able to float.

3. The density of lead is 11.3 times the density of water. How would you modify
the design of your boat to make it float.

4. What is the buoyant force on the metal and wood objects in this activity?
Explain.

5. What was the weight of the wood when resting in the water? Explain.
6. Would an object weigh more or less if there were no atmosphere on Earth?

7. If a block of metal and a block of wood of identical mass were submerged,
would the buoyant force on both be the same? Why or why not?

8. An average sized adult human has a volume of 68,000 cm3. If air weighs 1
Newton per cubic meter, what is the buoyant force of the atmosphere on such an
individual?

9. What should be added to raise or lower the egg? Explain.
10. Why did the egg rise when salt was added to the system?
11. Will a ship ride higher in an ocean or a lake?

12. Will more or less of an iceberg be submerged if it is floating in fresh water?
Explain.

13. Petroleum geologists and engineers often flood oil wells with salt water to
increase production. Why? '

43

APPENDIX 35

Investigations of Bernoulli’s Principle.

Concepts to investigate: Bemoulli’s principle, manometer, atomizers, pressure
differential, lift and flight.

Materials: Table tennis balls, thread, tape, paper, straw, food coloring, pencil,
paper, tape, straight pin, funnel, and tubing.

Principles and Procedures:

Part 1: Air stream between two objects: Using a straw, blow air between
two ping pong balls hung about 10 cm apart. Bend two ends of a piece of paper.
Stand the piece of paper on the edges. Blow under the piece of paper and see
what happens. Record all observations. Can you explain why this happens?

Part 2: Measuring pressure with a straw - manometer: Using two straws,
place one straw in a colored water solution. Blow air through the straw over the
other straw and make observations. Measure the height the colored water rises.
Record air pressure when blowing air above the straw. 10 centimeters is about
10 mbar. Make comparisons to the actual air pressure which is 1013 mbar. By
shortening the straw, you can create an atomizer which is used in a lot of garden
Sprayers, perfumes and spray fertilizers. Make observations.

Part 3: Airfoil: Wings, rudders, and propeller blades are examples of
airfoils, surfaces used to control the speed and direction of aircraft. Tape 3 piece
of paper to a pencil. Put pencil against lip and blow air over paper. Record all
observations. Try blowing at different speeds.

APPENDIX BS (cont)

Questions.

1. Given two straws, how can you separate the two table tennis balls without
blowing them apart? Explain.

2. The table tennis balls in part 1 appeared as though they were attracted to
each other. Explain why this is incorrect.

3. The reduction in fluid pressure is proportional to the square of the speed of
the fluid. On the basis of this relationship, how much higher would water move in
a straw if the velocity of the air across the top doubled?

4. Could you develop an anemometer which is a device that measures wind
speed using Bemoulli’s principle? Explain.

5. Hurricanes and tornadoes may cause houses to explode. Explain.
6. Why is it dangerous to stand near a fast moving train? Explain.

7. Ships that pass close to each other run the risk of a sideways collision.
Explain.

8. What is the relationship between the speed of air across the paper and the
amount of lift in part 3?

9. Some race cars have elevated inverted wing-like structures known as
spoilers. What effect may such spoilers have on a race car's performance?

45

APPENDIX C1

Explain your answers. (3 points each)

1.

9999’!“

10.

11.

12.
13.

14.

15.
16.

17.
18.
19.

20.
21.

23.

24.

As an ice cube in a glass of water melts. does the level of the water in the glass rise, fall,
or stay the same?

Why are bottles of intravenous fluid hung so high over the hospital bed?

Why are high altitude directions given on food packages?

What is the advantage of a pressure cooker?

Why do spears, arrows, needles, etc. have pointed tips?

You are standing on a scale when all of the air is suddenly sucked out of the room.
Bravely, you look at the reading on the scale before you run out of the room in search of
breath. Was the reading with the air removed higher, lower or the same as that before
the air was removed?

You are sitting in a boat in a quiet pool. You pick up a rock from the bottom of the boat
and drop it into the water. Does the water level in the pool go up, go down, or stay the
same?

Why do champagne bottles have wire cages on them while other wine bottles do not?
Why do women wearing high heels have more trouble than their heavier male
counterparts when walking across soft ground?

Would you rather be stepped on by a 1000 lb. elephant with a one square foot or a 120 lb.
female wearing high heals with one square centimeter?

Why do bicycle tires need to be pumped up to higher pressure than automobile tires when
they don't need to support as much weight?

Why do your ears “pop” when you travel in an airplane or drive in the mountains?

Many community water towers have the shape shown in the diagram. Doesn't this shape
represent an unstable situation, since the center of mass is so high and the support area
so small? Wouldn't it be easier and safer to just build a cylindrical tower with vertical
sides? Why do water towers have this strange shape?

Farm silos have bands around them to provide sturdiness to the walls. Why are the
bands closer together near the bottom of the silo than at the top?

Scuba divers need to be wary of the “Bends”. What are the “Bends“?

Atmospheric pressure is 14.7 lbfinz. If you multiply this by the surface area of your body
in inches, you obtain a huge force. Why aren’t we all crushed?

Take a look at a non-retractable ball point pen. Somewhere on the barrel you are very
likely to find a small hole. Why do they do this?

If you are caught in quicksand, what is the best way to escape?

Why do golf balls have dimples?

Why are airport runways longer in Denver than in San Francisco?

Why are scuba divers instructed to exhale while ascending to the surface?

If a helium balloon is released into the air, it rises upward until it finds an equilibrium
position and comes to rest. A sinking submarine, on the other hand, simply sinks to the
bottom, without ever finding an equilibrium position in the water. Why?

If you have ever been snorkeling, you may recall that snorkels are only a fraction of a
meter in length. Why isn’t it possible to buy a longer snorkel, so that you can dive
deeper?

Why are tennis balls stored in pressurized sans?

46

APPENDIX CZ

Show all workl 5 points each

1. Which has a the greater density - 1 kg of water or 10 kg of water? Explain your answer.

2. When finding the volume of the two 35mm canister in the lab, how did they compare?

3. If one material has a lighter density than another, does this mean the molecules of the first
must be heavier than those of the second? Explain.

4. Vlfill an empty balloon have precisely the same apparent weight on a scale as one that is filled
with air? Explain.

5. Find the density of a piece of wood. Show all work for full credit.

6. Given an irregular shaped object find its density.

47

APPENDIX C3

What is the total force and the absolute pressure on the bottom of a swimming pool 22.0m
by 12.0 m whose uniform depth is 3.5 m? What will be the pressure against the side of
the pool near the bottom?

A king orders a gold crown having a mass of 0.5 kg. When it arrives from the
metal-smith, the volume of the crown is found to be 185 cm3. is the crown made of gold?

A 50 kg woman balances on one heel of a pair of high heel shoes. If the heel is circular
with radius 0.5 cm, what pressure does she exert on the floor? Compare this to the
pressure exerted by a 1500 kg elephant standing on one foot (area = 800 cmz).

A car sinks to the bottom of a 15 m deep pool of water. A door on the car measures 1 m
by 0.6 m. (a) If the inside of the car is at atmospheric pressure, what force most one
exert on the door in order to open it? (b) What procedure might one use to escape from
the submerged vehicle?

Calculate the buoyant force on a solid object made of copper and having a volume of
0.5m3 if it is submerged in water. What is the result if the object is made of steel?

A steel cube 3 cm on a side floats in a pool of mercury. What volume of the cube is
above the level of the mercury surface?

A man decides to make some measurements on a bar of gold before buying it at a cut
rate price. He finds the that the bar weighs 2000 N in air and 1600 N when submerged in
water. Is the bar made of gold?

What is the approximate difference in air pressure between the top and the bottom of the
World Trade Center buildings in New York City? They are 450 m tall and are located at
sea level. Express as a fraction of atmospheric pressure at sea level. What would be the
approximate force on an eardrum of area 0.5 cm2 if your ears did not pop?

48

APPENDIX C4

Explain your answers. (3 points each)

1.

10.

11.

12.

As an ice cube in a glass of water melts, does the level of the water in the glass rise, fall,
or stay the same?

Why are bottles of intravenous fluid hung so high over the hospital bed?
Why do spears, arrows. needles, etc. have pointed tips?

You are standing on a scale when all of the air is suddenly sucked out of the room.
Bravely, you look at the reading on the scale before you run out of the room in search of
breath. Was the reading with the air removed higher, lower or the same as that before
the air was removed?

You are sitting in a boat in a quiet pool. You pick up a rock from the bottom of the boat
and drop it into the water. Does the water level in the pool go up, go down, or stay the
same?

Farm silos have bands around them to provide sturdiness to the walls. Why are the
bands closer together near the bottom of the silo than at the top?

Atmospheric pressure is 14.7 lbfinz. If you multiply this by the surface area of your body
in inches, you obtain a huge force. Why aren't we all crushed?

If you are caught in quicksand, what is the best way to escape?
Why are airport runways longer in Denver than in San Francisco?

A king orders a gold crown having a mass of 0.5 kg. When it arrives from the metalsmith.
the volume of the crown is found to be 185 cm3. Is the crown made of gold?

A car sinks to the bottom of a 15 m deep pool of water. A door on the car measures 1 m
by 0.6 m. (a) if the inside of the car is at atmospheric pressure, what force most one
exert on the door in order to open it? (b) What procedure might one use to escape from
the submerged vehicle?

Calculate the buoyant force on a solid object made of copper and having a volume of
0.5m3 if it is submerged in water. What is the result if the object is made of steel?

49

APPENDIX D

Demonstration One: Materials: Garbage bag, and vacuum cleaner. Have
someone climb into a garbage bag with just their head sticking out. Place the
hose of the vacuum cleaner in the bag with them. Turn on the vacuum. The
student will experience 14.7 lb/in2 of pressure.

Demonstration Two: Materials: empty pop can, burner, tongs, and bucket.
Heat some water in a pop can. Make sure there is barely enough water to cover
the bottom of the can. Make sure the water is at a good boil and then place the
can upside down in a pool of cold water. The can will crush because of the
decreased pressure inside of the can. Decreased pressure inside and normal
pressure outside.

Demonstration Three: Materials: String, onion bag, balloon, 6' of PVC that is
6" in diameter, end cap for 6" PVC, coupling and female threaded hub for 6"
PVC, threaded hub for 6" PVC a plastic graduated cylinder, and an metal eye
hook. The eye hook is placed in the end cap at the center. The end cap is
placed on the 6’ piece of pipe. The other end gets the female coupling. See
Diagram Below. Make sure you put the string through the eye hook to be able
to pull the balloon down the tube. The graduated cylinder needs the end cutoff
and a hole should be drilled in the top of the threaded end cap. Place the
graduated cylinder in the hole. This had to be a tight fit and place putty around
the graduated cylinder. Put string through the graduated cylinder and place
balloon in the onion bag. Fill the tube full of water and seal off the threaded
end. Pull the string up and down to remove any air bubbles and then you should
be ready to go. The volume change can be measured with graduated cylinder.

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cylinéef'

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APPENDIX D (cont)

Demonstration Four: Materials: Vacuum pump, marshmallow and sealed
container. Place the marshmallow in the sealed container and suck out the air
using the vacuum pump. Let it run for a few minutes, making all observations.
Then turn, off vacuum pump and release the pressure. Watch what happens.
The marshmallow shrinks smaller than original size.

Demonstration Five: Do the same thing in demonstration four but use a balloon
instead. Ask the question did the balloon actually gain air?

Demonstration Six: Place warm water in the same sealed vacuum pump jar.
Turn the vacuum pump on and watch what happens. The water will begin to
boil. Have students explain this phenomena. Make sure students can feel the
water before and after.

Demonstration Seven: Blow air between two pieces of paper and the pieces of
paper will get pushed together because of the decrease of pressure in the
middle.

51

BIBLIOGRAPHY

52

BIBLIOGRAPHY

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54

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