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MSU I: An Affirmative Action/Emul Opportunity Institution
MUN-9.1

TEACHING ENERGY
TO
HIGH SCHOOL GENERAL BIOLOGY STUDENTS

By
Laurie Ann Vargo

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

MASTER OF SCIENCE

College of Natural Science
1 997

ABSTRACT
TEACHING ENERGY

TO
HIGH SCHOOL GENERAL BIOLOGY STUDENTS

By
Laurie Ann Vargo

The purpose of this energy unit was to teach the basic concept of energy
to ninth and tenth grade general biology students. The unit addressed the
general concept of energy, and compared physical and biological energy; laws
of thermodynamics, energy stored in chemical bonds, and energy transfer in an
ecosystem from the sun to living organisms.

The unit was built around a thematic approach to teaching science, and
included several laboratory experiments and "hands-on“ activities to promote
conceptual understanding of energy. The instruction sought to incorporate
writing across the curriculum and elements of the constructivist philosophy. An
additional goal of the unit was to help students feel comfortable with science
and scientific thinking.

Student interviews, comparison of pro-test and post-test scores,
evaluation of journal entries, student writing samples, exit student evaluations.
and cooperative learning group reports/projects were evidence that student
learning was enhanced by the pedagogic methods utilized. The students were
enthusiastic learners who constructed their own knowledge of energy.

I dedicate this thesis to
my mother June
and
my father George
whose example, encouragement, and love,

were my inspiration

ACKNOWLEDGMENTS

I would like to thank the following for their
assistance in the completion of this study:
Dr. Merle Heidemann
Dr. Clarence Suelter
Dr. Howard Hagerrnan
Dr. Marty Hetherington
Dr. Zeynep Ustunol
Dr. C.W. Anderson
All of my students

iv

 

TABLE OF CONTENTS

 

 

 

LIST OF FIGURES ..... vii

LIST OF TABLES viii

CHAPTER 1

INTRODUCTION 1
A. Statement of the Problem and Rationale for the Study 1

 

B. Literature Review of the Pedagogic Problem of Teaching Energy ........ 9
C. Review of the Literature that Supports the Instructional Approach to

 

 

 

 

 

 

 

 

 

 

 

 

Teaching Energy 13
CHAPTER 2
IMPLEMENTATION OF THE UNIT 22
A. Demographics of the Classrooms ...... 22
B. Pro-Unit Assessment 23
0. Description oftheCIinical Interviews - ....................... 25
D. What Happened During the Interviews. 26
E. Evaluation of Clinical Interviews as An Assessment Strategy .............. 31
F. Outline of the Unit 31
G. Audio-Visual Aids Used
I-l. Laboratory Exercises, Demonstrations, and Other Activities ................ 36
I. New Pedagogical Techniques ............. - .......... 44
CHAPTER 3
EVALUATION 47
A Pie-test and Post Test Results 47
B. New Teaching Strategies- - 52
C. Student Interviews 54

 

CHAPTER 4

DISCUSSION AND CONCLUSIONS 57
AAspectsoitheUnitWhich Were Effective- -- 57
B. Aspects of the Unit Needing Improvement .......... 60
C. Overall Evaluation and Conclusion - - 62

BIBLIOGRAPHY

 

APPENDICES

 

Appendix A: Daily Log of Activities

Appendix B: Clinical Interview Transcripts

Appendix C: Laboratory Activities

Appendix D: Pictures For Concept Maps

Appendix E: “The Role of Microorganisms in Food Production",
Information Sheet

Appendix F: Cartoon Overlays of Photosystem Capturing Energy
and Energy Flow

Appendix G: Journal Entries

Appendix H: Energy Transformations Worksheet

Appendix I : Energy Quiz

Appendix J: Models of the Processes of Photosynthesis and
Respiration

Appendix K: “Boosting" Electrons Metaphor

Appendix L: Story of Photosynthesis

Appendix M: "From Sugar Making To Sugar Burning"

Appendix N: Pyramid of Energy Worksheet

Appendix 0: Ecocolumns

Appendix P: A Learning Setting Vs. A Work Setting

Appendix 0: 9-Patch Ouilt Metaphor

Appendix R: Pre- and Post Test

vi

LIST OF FIGURES

Figure 1 - Pro-Unit Synopsis of Focus Students' Understanding ......................... 30
Figure 2 - Synopsis of Agenda .................................................................................... 35

vii

LIST OF TABLES

TabIe1-Pre—andPostTestPooledDataofAII Classes ...................................... 48

viii

CHAPTER 1

CHAPTER 1

INTRODUCTION

Statement of the Problem and Rationale for the Study

Elkana (1974) observes that ‘conceptual revolutions’, ‘conceptual
evolutions’, or ‘conceptual frameworks’ are talked about frequently, but never
defined by those who discuss them. Concepts can be thought of as ideas
scientists use when they plan new experiments or develop new mathematical
formulas. The concept must be accompanied by content. Educators use these
concepts to plan what content to teach. According to Elkana (1974), von
Helmholtz proved correctly and generally the law of conservation of energy.
However, he did not have a clear idea of the energy with which he worked. This
illustrates what seems to be a general feature of how scientific concepts
develop, namely that they are In a state of flux while we discovery is being
made.

According to Richard Feynman (1975) the law of the conservation of
energy states that there is a certain quantity. which we call energy, that does not
change in the manifold changes which nature undergoes. That is a most
abstract Idea, because It is a mathematical principle; it says that there is a
certain quantity which does not change when something happens. It is not a

‘I

2

description of a mechanism, or anything concrete; it is just a strange fact that we
can calculate some number and when we finish watching nature go through her
tricks and calculate the number again, It is the same. Feynman also say it is very
difficult to define and describe the Idea of energy.

However, “energy Is one cornerstone of the sciences. Energy may be the
most powerful theme connecting and unifying the sciences“ Martin (1992).
Holman (1986) has suggested that teachers should develop five conceptual
areas with regard to energy: the meaning of energy, energy transfonnation. the
storage of energy in chemicals, the degradation of energy, and the conservation
of energy during transformation.

Energy is a concept which many sources, including dictionaries, high
school textbooks, and encyclopedias have defined. These are not scientific
definitions. The American Heritage Dictionary (1992) defines energy as 1. The
capacity for work or vigorous activity; vigor; power. 2.a) Exertions of vigor or
power: a project requiring a great deal of time and energy. b) Vitality and
intensity of expression: a speech delivered with energy and emotion.
3.a)UsabIe heat or power: b) A source of usable power, such as petroleum or
coal. 4. The capacity of a physical system to do work. Holt, Rinehart, &
Winston's. Wash 996). defines energy 88
capacity for doing work, often described as the ability to make things move or
change. A scientific definition from a physics text may state that energy is the
capacitytodowork,workultimatelydeflned intermsofaforcetimesa
displacement Perhaps these definitions of energy contribute to students'

misconceptions.

It appears bioenergetics is more difficult for students to comprehend than
energy usage in mechanical systems. The conversion of one form of energy Into
another is relatively straightforward in mechanical systems. A barrel of water on
a mountain top has a certain amount of potential energy (energy of position),
which is proportional to the height of the mountain (and, of course, to the
quantityofwaterinthebarrel). lfthewaterispoured overtheedgeofacliff, the
potential energy drops as the waterfalls, but the kinetic energy (energy of
motion) increases proportionately. When the water strikes the floor of the
canyon, an amount of heat energy is released equal to the kinetic energy of the
water just before it reached the canyon floor, and this amount, in turn is equal to
the potential energy the water had on the mountain top (we neglect the effect of
air friction and otherwise assume ideal conditions). If the water is allowed to
strikeapaddlewheel, ontheotherhand, apartoftheenergy maybeobtained
as work, although the rest is still converted into heat Energy therefore, may be
converted from one form to another but in these transformations, the total
amount of energy remains constant. This Idea of energy transference is more
difficult to convey in living systems.

Incredibly, all the processes of life and, indeed, all the energy and matter
in the universe obey two simple laws ofthennodynamics. The first law
ofthennodynamicsstatestl'iatenergy may neitherbecreated nordestroyed, but
It can be transformed. Although energy is transferred from one object to another
andtosomeextentisevenconvertedfrom oneforrntoanother, noenergyis

4
created or destroyed by transfer or conversion. This law does not apply to
nuclear changes, where energy can be produced from small amounts of matter.
The second law says that energy inevitably disperses, dissipates, and scatters
on its way to becoming heat. In other words, within an isolated system, energy
does run down in Its ability to do work on Its way toward being heat. Heat can
be used to do work, but the energy transfer is always accompanied by a loss of
order or organization.

Life represents a creation and maintenance of ordered (low entropy)
structures. Entropy, often referred to as randomness, is the energy within a
given system, that Is no longer available to do work. Thus, within any isolated
system, as energy exchanges occur, entropy increases. To form and preserve
the highly ordered arrangement of molecules and the organized network of
chemical changes in living organisms, they must continually get and use high-
quallty matter resources and energy resources from their surroundings. When
these resources are used, they become disordered, low quality (high entropy)
heat and thus, waste matter to the environment. All forms of life are tiny pockets
of order (low entropy) maintained by creating a sea of disorder (high entropy) in
their environment.

Of particular interest in this unit, is the energy that can be obtained from
chemical compounds. In this respect, chemical energy is the energy a molecule
hasbyvirtueofthe kindsofatomsitcontainsand themanner in whichtheyare
linked together; chemical energy may be considered as a type of potential
energy. Explosions and flames are dramatic examples of reactions in which

5
chemical energy is released. The heat and light that are characteristic of these
reactions comes from the breakdown or rearrangement of the chemicals
involved; that is, the energy released was present originally in the starting
molecules as chemical energy. For example, in a battery, chemical energy is
converted to an electric current. In turn, the energy can be used to run a motor
which performs mechanical work.

To make matters more complicated, sources of energy flow through the
biomass of plants, animals, and microorganisms in complex food chains on
their way to becoming heat. Chloroplasts in plant cells manufacture sugar using
the energy of sunlight, in the process called photosynthesis. Mitochondria, in
both plant and animal cells, break down or utilize the chemical energy in sugar
to make ATP (Adenosine Triphosphate), in the process called respiration. This
seemingly simple design represents the flow of energy through life.
Chloroplasts inside plant cells trap the energy from light and transfer it to the
bonds of sugar molecules. Glucose, the storabla and transportable fuel of the
living world, is also living organisms' basic building material. Mitochondria use
oxygen to burn (i.e., break down sugar, making ATP, a potential source of
energy in the process). ATP provides energy by creating molecules that make
life's work possible.

Energy involved In the synthesis of substances by a living organism is
transferred when another organism oats and than oxidizes those substances.
Not all energy from the oxidation is transferred to the living organism. A lot of the
energy is transferred to the environment This energy Is said to be "lost“I from the

6
ecosystem since it cannot be transferred to building up new material or to other
processes in living things. Thus, energy flows through the ecosystem; it is not
cycled.

The relationship between life and energy is complex. If I could succeed in
linking energy between mechanical and living systems, I could proceed with
teaching the 'big idea" or universal idea of energy. “Failure to convey the crucial
role energy plays in all levels of life may interfere with the acquisition of
biological understanding of energy and its importance in living systems.“
(MEGOSE, 1990) To be scientifically literate, students need to have a deep and
connected understanding of the "big ideas" of science. This instructional unit
attempts to integrate biological, chemical, and physical principles using energy
as a platform. It is the first attempt l have made to help students better
understand the interaction and inter-dependanca of organisms and events in
the world.

Teachers are encouraged by AAAS Project 2061, Science For All
Americans (1990), to focus on the big ideas of science and not layers of
technical detail. It is these details which often mask important ideas and turn
kids off to science. Concepts leamad in depth and with understanding can be
applied to new situations or problems. Less is more, in teaching, means that
exposure to fewer topics leads to deeper understanding. Traditionally, l have
concentrated on the details of biology and l have expected my students to
memorize facts and lnforrnatlon. I would give out the information in lectures, we
would read the chapter, do an activity, complete a study guide or reading guide,

7
then take a test over the information. I rationalized this was perfectly all right
because, after all, this is how I had leamad.

When I began my research at MSU, l was developing labs and activities
which involved the microbiology of food. After some careful reflection and
consideration, I felt a detailed unit on food microbiology would be great for
advanced science students Unfortunately, this advanced study would not serve
maneadsofthemajorltyofmystudentswhowereinmygeneral biology
classes. Therefore, during the development of the unit I found my focus
changing to the big idea of energy usage In biological systems.

During the teaching of this new unit. I did not teach the details of
respiration or photosynthesis. Students were not asked to memorize the Krebs
cycle or the light and dark reactions of photosynthesis. Rather, lfocussad in on
the big idea of energy usage in living things and the relationships with physics
-and chemistry. The chemical equations for respiration and photosynthesis
served only to show the relationship between the energy-producing and
energy-using life processes. The Laws of Thermodynamics incorporated the
physical aspect of energy dynamics. According to Martin (1992), themes link
together the "big ideas“ so that we can see connections among ideas in
science. When we understand ideas in science we can describe their
relationship to other ideas. It is possible to find relationships among batteries,
photosynthesis, and respiration.

The decision to change and expand the 'energy‘ unit previously taught
as photosynthesis, respiration, and energy flow through an ecosystem, came

8
after I realized how superfluous details were when students did not see any
connections between the concepts. Energy is a powerful integrating theme
among widely different areas of science. For example, batteries can be
”charged“ with energy which is available for lighting a bulb or turning a motor.
So too, In plants, the charging process involves conversion of energy in some
form into potential energy. So plants and batteries are similar in that they both
store energy.

Focussing on the'big idea" of energy allowed me to teach concepts in
depth and with understanding which could be applied to new situations or
problems. Dealing with fewer details lead to deeper understanding as
avidenmd by the data gaflrerad from the assessment strategies.

Children become familiar with the neighborhood of science in the same
ways that children become familiar with their own neighborhoods-by asking
questions. I presented many ideas which encouraged students to ask questions
and to invent answers to the questions they made up. In Kathleen Roth's paper
(1991) she quotes Dr. Rutherford as saying, I'students need to learn that..what
you learn is worth laaming, It can be fun, it can be helpful, It will enrich your life,
and you ought to be doing it most of your life". She also suggests students need
many opportunities to 'tie" science, to manipulate objects, to ask questions, and
to make up stories to explain their own observations. Ms. Roth states, I‘to teach
children how to use a compass to explore the neighborhood of science in
meaninng ways, teachers must help students learn how to change their stories

about their experiences so that they see science as a process of sense-making

9
and a process of creating increasingly satisfying explanations of the natural
world.“ I tried to accomplish these things with the activities and laboratories
included in this unit.

Since I did notfind the perfectsetofactivitiestochallenge studentsto
rethink their naive ideas about energy, I captured the students interest with a
varietyofmaterlals. Writing assignmentswareusad asatooltogetstudemsto
share, try out, examine, contrast and revise Ideas about energy. In the past, I
used writing assignments to hold students accountable for completion of work
and to enable me to grade them "objectively'. During this unit. I used student
writing to reveal student thinking and to guide my planning and teaching. I also
used clinical interviews for the first time in this unit to illicit information regarding
energy usage in biological systems from three students with varying ability.

In sequence, the energy unit followed the study of basic biochemistry,
the study of cell structure, function, and reproduction, the study of Mendelian
and human genetics and heredity. It preceded the study of evolution, the study
of population dynamics, the study of ecosystems, and the study of diversity in
living things.

Literature Review of the Pedagogic Problem of Teaching Energy
Across the field of research studies on pupil’s ideas about energy,
several recurring concaptualizations of energy have emerged. According to
Driver, at al., 1994, energy is seen as,
associated only with animate objects;

1 O

-a casual agent stored in certain objects;

-linked with force and movement;

-fuel;

-a fluid, an ingredient or a product
Furthermore, Hapkiewicz (1992) defined several misconceptions students have
about energy. These include; 1) that energy is truly lost in many energy
transformations, 2) there is no relationship between matter and energy, 3) if
energy ls conserved, why are we running out of it?, 4) energy can be changed
completely from one form to another(no energy losses), 5) things “use up “
energy, 6) energy is confined to some particular origin, such as what we get
from food or what the electric company sells, 7) an object at rest has no energy,
8) the only type of potential energy is gravitational, 9) energy is a “thing“. (This is
a fuzzy notion probably because of the way we talk about newton-meters or
joules. It is difficult to imagine an “amount of an abstraction“) and, 10) the terms
“energy“ and “force“ are interchangeable.

Solomon (1983) asked children to write 3 or 4 sentences showing how
they would use the word ‘energy’. Human activities, health, food, and fuels all
figured prominently in pupils’ responses. Solomon discovered four themes
among the responses. Two of these were:

1. vitalism, in which energy is thought to be needed for life. (“When we
run out of energy we need medicine and vitamins’ and “Exercise is good for
you, it builds up your energy)

2. activity, In which we are thought to need energy to move 'When we run

1 1
out of energy we need food and rest’. ‘Exercises use-up energy, than you
become tired.’

By the age of 11 most children have a fairly correct view of anatomy and
theovarall function of systems. Gellert (1962) found older students view some
food as being turned Into energy and children under 9 think that the food
vanishes completely in the process. I'Goodness“ is extracted somehow. School
pupils aged 13-14, do not grasp or are unaware of, the meaning of the word
'food” as a material that serves as a substance for respiration. Simpson (1983)
found a common misconception that digestion is the process which releases
usable energy from food. It appears this misconception arises from students
linking two acceptable ideas ( 'energy is obtained from food’ and 'digestion is
the breakdown of food').

Gayford (1988) reports that 17- and 18-year old biology students
considered that energy flows (or is transported) from place to place in biological
systems and that It can be stored like a material. They thought in tenns of
energy ‘fomd’ or ‘used’ in biological processes rather than in terms of energy
conversions. Of Gayford’s sample, 79% did not understand that biological
processes such as respiration involve energy conversions. They thought that
respiration fOI'ITIS energy which is used in synthesis reactions. Children tend to
believe that energy is used up by living things in general and that plants use up
energy in growing. This includes the notion that plants make direct use of solar
energy for vital processes and that plants convert energy from the sun directly
into matter. Scientists’ ideas contrast with this conception because plants use

1 2
energy from the sun to convert carbon dioxide and water into sugars. Students
appear to think that energy is created or destroyed in different life processes
(Gayford,1986, Mintzes,1984, Smith a Anderson,1984).

Roth and Anderson (1985) found many children expressing the idea that
plants make food for the benefit of animals and people rather than for the plants
themselves. Children did not appear to recognize that photosynthesis is the
process by which energy from the environment becomes available to plants and
than to animals.

Children appear to consider chlorophyll as a food substance, a
protection, a storage product, a vital substance like blood, or something that
makes plants strong (Barker,1985). The role of chlorophyll in absorbing light
energy was seldom appreciated by students, even after teaching. Only 29% of
12- to 13- year olds and 46% of 14- to 16- year olds in Simpson and Arnold's
study understood chlorophyll as a converter of light energy to chemical energy
(1982). Most of the students in Simpson’s study (1983) did not understand
energy transfers in living things; they believed that plants get the energy for all
their processes directly from the sun and light was considered to be made of
molecules.

Barker (1985) found most children use the words ‘heat’ and ‘light’
interchangeably in the context of photosynthesis. Nearly 80% of a sample of 13
year-olds thought that plants use heat from the sun as an energy source for
photosynthesis. Most considered that the sun Is one among many sources of
energy for plants, others being soil, minerals, air and water.

1 3

Having leamad that plants take in carbon dioxide, water, and minerals,
pupils tend to regard these as the food of plants and when food is associated
with energy, these inorganic substances are assumed to contain and supply
energy.

Brumby (1982) found the integration of ideas about feeding and energy
Into an ecological perspective is not evident in the thinking of many students.
Only half of a sample of undergraduate biology students, explained the
phrases, ‘life depends on green plants’ and ‘the web of life’, in terms of food
chains. A minority of these mentioned harnessing solar energy or
photosynthesis as the reason why green plants are crucial in the food chain.
Few students appear to relate their ideas about feeding and energy to a
framework of ideas about interactions of organisms.

Several studies have found that most students interpret food web
problems in a limited way, focusing on isolated food chains (Webb & Boltt,
1990, Griffiths & Grant, 1985). Little evidence exists that students reason about

interdependence or energy flow in an ecosystem.

Review of the Literature That Supports the Instructional Approach
to Teaching Energy

AAAS Project 2061 (1991) calls for scientific literacy for all Americans
emphasizing the notion that all have a capacity for scientific ways of thinking
and using scientific knowledge and ways of thinking for individual and social
purposes. The Michigan Essential Goals and Objectives, K-12 (1991)
emphasizes that students should 1) use scientific knowledge to describe.

1 4
explain, predict, and design real-world systems or phenomena, 2) construct
new scientific knowledge, through asking appropriate questions, developing
solutions to problems, interpreting sources of information, reconstructing
previously leamad knowledge, 3) reflect on scientific knowledge, including
justifying and testing beliefs with evidence and logic, criticizing arguments,
describing limits to knowledge, making connections among ideas, taking a
historical and cultural perspective on the development of knowbdge, and
describing Interactions among science, technology and society.

In many cases there are significant differences between children’s
notions and “school" science. They use these naive theories to explain real
world events before they have had any science instruction. The students’ naive
theories affect what they perceive to be happening in classroom demonstrations
or laboratory experiments, and they continue to attach their naive meanings to
technical terms. Children’s ideas about science are shaped by pemonal
experience with phenomena. Driver, at al. (1994) state, “investigations have
indicated that such ideas are to be seen as more than simply pieces of
misinformation; children have ways of constructing events and phenomena
which differ substantially from the scientific View.“ Studies also indicate that
these notions may persist into adulthood despite formal teaching.

Once the teacher has identified the nature of any differences between
pupil’s thinking and the science viewpoint, then it becomes easier to plan
activities which will support intended Ieaming. The skillful teacher picks the
teaching method to suit the teaching-leaming situation. When one plans

1 5
carefully, one is forced to become master of the material and the methods of
teaching it

Teaching is helping pupils to learn. In the final analyses the test of one's
success as a teacher is how well the pupils have leamad. Unfortunately, or
perhaps fortunately, there is no one best method of teaching that will always
generate a high degree of pupil Ieaming. Rather, there are any number of
strategies, tactics and techniques that may or may not be effective in a particular
situation. The most effective teachers are those who can vary their styles, or
whose styles are so flexible that they encompass a great number of strategies
and tactics, and are therefore readily adaptable to the different sorts of teaching-
Ieaming situations that may develop.

There is not any one lesson plan form or unit plan form that will ensure
that you will reach your class. The form of the plan is insignificant; It is the
substance of the lesson, unit, or course plans by which you will succeed or fall
in reaching your objectives. Planning is absolutely essential for effective
teaching in that it points the instruction and subject matter in the course, unit, or
lesson toward the Ieaming.

In recent years, as in earlier ones of the century, many theorists and
practitioners have attempted to make what goes on in the classroom more
consonant with the reality of the world outside the classroom. They urge
educators to give greater recognition to the various skills needed to function in
society as human being, worker, citizen, consumer, parent; to develop a more
sophisticated awareness of the uses of knowledge; and to become concamed

1 6
not only with knowing about but also in knowing how. Planning is essential to
accomplish this goal.

The notion that pupil Ieaming is more meaningful, more thorough, and
therefore more usable when pupils seek out and discover knowledge, has been
held by educational theorists for centuries. If teaching will give pupils
opportunities to draw conclusions from data that are provided or that they seek
out for themselves, the pupils will benefit Whether an individual's ideas are
affirmed and shared by others in classroom exchanges has a part to play in
shaping the knowledge construction process also.

In the early 1980’s findings in cognitive science suggested new
approaches to teaching in science and mathematics. The fundamental view of
the learner that emerged was as follows: First, learners construct
understanding. They do not simply mirror what they are told or what they read.
Student naive theories are inevitable because learners construct meaning even
in the absence of complete information. Second, to understand something is to
know relationships and third, all Ieaming depends on prior knowledge (Resnick,
1983). To learn something new you have to start with the cognitive structures
and strategies that you already have (Michaels & O'Connor, 1990).

Constructivist research emphasizes that students construct knowledge in
the sense that they interpret new experiences in the context of prior knowledge,
experiences, episodes, and images. The constructivist model requires that
teachers facilitate the Ieaming process by 1) providing age appropriate

materials, tools, and resources, 2) initiating interest (often with a discrepant

1 7
event), 3) asking directed questions, 4) providing and encouraging a
collaborative atmosphere, 5) encouraging student inquiry and exploration, 6)
suggesting familiar and meaningful contexts for concepts, 7) providing time for
reflecting, 8) encouraging verbal and written communication of ideas, and
9) assessing by student understanding (Yager, 1991).

Efforts to translate constructivist research into classroom practice is
evident in the use of instructional models. New Directions Teaching Materials
(1992 ) were created to help teachers develop scientific literacy and conceptual
understanding for all students. One of the important goals of these materials is
to connect students' developing scientific ideas with the ideas they already use
to make sense of the world. I incorporated information from the New Direction's
“Food, Energyand Growth" unit into my new energy unit.

Novak and Gowin (1984) state that we as teachers need to help students
"learn how to learn“. They introduced concept maps to convey understanding of
a Ieaming task and to relate what is known to the new thing being leamad.
Concept maps are structured hierarchically and the relationships between
concepts are indicated by “linking“ words. Two or more concepts linked together
form a proposition. These propositions represent meaningful relationships
between concepts. Concept maps often point out relationships between
concepts or between concepts and specific examples that we assume students
are making on their own, but that may require more direct teaching. This
assessment of understanding provides teachers and students with an additional

1 8
tool for nurturing understanding.

My pedagogic techniques, used prior to this unit, required students to
learn a large amount of lnfonnation, interpret that lnfonnation, and use that
information to solve scientific problems, all in a short period of time. I moved the
studentsfromonetopictothe nextwlthnoexplanation oftheconnections
between those topics. Learning, especially when It involves abstract concepts
such as energy, is a complex process. For most students it takes time to really
learn something. Students required to learn too much material in too little time
will not retain that knowledge to use it in their subsequent work in science. It
requires activity, discussion, and establishing relationships among various
components for students to learn scientific concepts.

In the words of Anderson and Roth (1989), “understanding consists of the
ability to use scientific knowledge to describe, explain, predict, and control the
world around us”. Students should develop knowledge that is conceptually
coherent and integrated with their personal knowledge of the world, as well as
being scientifically accurate (Anderson and Roth, lbid). Students need time to
develop the skills to learn how to learn; to use their knowledge to control their
world.

A human belng‘s experience always includes and is strongly influenced
by our social interaction with other humans. We can only know what we have
constructed oumelves, but such Ieaming always takes place in a social context.
Furthermore, social transactions play a critical role In the shaping of cognition.
According to Richmond and Striley (1995), “language is a mediator of the

1 9
cultural world and it becomes the essential partner of thought.“ Therefore, the
unit incorporated group work and cooperative Ieaming.

We use language to cope with our environment, to help us make sense
of our world, and to communicate how we can use the meaning formulated.
According to Anderson (1995), two problems that separate the successful from
the unsuccessful student is a problem of language, the second is a problem of
motivation or engagement

Paul Gee (1991) defines a "discourse“ as: “a socially acceptable
association among ways of using language, of thinking, and of acting that can
be used to identify oneself as a member of a socially meaninng group or social
network.“ He contends we should think of a discourse as an “identity kit“. This kit
comes complete with the appropriate costume and instructions on how to act
and talk so as to take on a role others will recognize. People come by a
discourse through “acquisition" and/or “Ieaming“. All humans receive one
discourse free through acquisition. This is our socio-culturally determined way
of using our native language in communication with family and friends who
share similar experiences. Gee refers to this as the “oral mode“. For example,
lower socio-aconomic black children use English to make sense of their
experience differently than do middle-class children. They have different
primary discourses using language, behavior, values and beliefs to give
different shape to their experiences.

Gee proposes that literacy can be understood as the control of
discourses that go beyond whatever discourse we first acquired within our

20
family. Reading and writing may be a part of the picture, but only a part
Becoming literate in any particular domain involves Ieaming a specific
discourse-particular ways of thinking, acting and valuing. Socialization of an
individual into knowledge Ieaming of the language, and activities of the
neighborhood of science, becoming a “member of the club“, is very important for
educators to accomplish. it is important to create a social context-a Ieaming
community of scientific inquiry-that will enable the “eliciting“, “challenging“, and
“contrasting“ of ideas; to support students in developing a connected, useful,
and reflective understanding of science. Students home-based ways of thinking
and using language should be extended and transformed by the teacher
(Michaels & O’ Connor, 1990).

Students rely on implicit schemas or frames: these guide interpretation,
explanation, and problem solving, and ultimately enable them to comprehend
or construct new knowledge in interaction with print Reading and writing tasks
require complex interpretive work and the development of new mental
structures to integrate information, rather than rote memorization or routine
manipulation of facts. My students were taught to memorize the facts and
regurgitate that information on quizzes and tests, prior to this unit I paid no
attention to the differences in thinking or to the differences in discourses.

Teachers bring their prior conceptions to Ieaming situations not only in
terms of their subject knowledge but also their views of teaching and learning.
These can influence their way of interacting in classrooms. Teachers must

spend time developing and practicing new and somewhat unfamiliar

21
pedagogical techniques. Teachers need to help students see the relevance of
scientific theory in their lives. Science must be seen as a way of life. We must
find what intellectual tools our scientific communities have produced that are
useful to all people whether they are scientists or not ( Anderson, 1995). The
key challenge for schools is to introduce and culture students into school-based
discourses, without denigrating their culturally specific values and ways of using
language. The implications for educators is to focus on issues of cultural and
social class differences in reasoning. We must help students use their different
discourse assumptions and styles to become scientifically literate.

It is my intention in this unit to take the time necessary to help students to
use what they know together with the discourse they used to leam that
information to correct misconceptions. Writing assignments and discussions are
going to be utilized to expose students to school based scientific knowledge.
Students will be taught to use scientific knowledge and ways of thinking for

individual and social purposes.

CHAPTER 2

CHAPTER 2

IMPLEMENTATION OF THE UNIT

Demographics of the Classrooms

This unit was implemented at an urban high school with a student
population of approximately 1500 economically and ethnically diverse students.
American lndians make up two percent (2%) of the population, Asians, six
percent (6%), African Americans, twenty percent (20%), Hispanics, eighteen
percent (18%), and Caucasians, fifty-four percent (54%). Sixty-eight percent
(68%) of the students attend class at least eighty-five percent (85%) of the time.
Well over half of the student population are eligible for the free or reduwd lunch
program.

The unit was introduced into three introductory biology classes with a
total of 68 students. The classes predominantly were mixed freshmen and
sophomores. None of the students had studied biology previously, although
most had been exposed to the life and physical sciences in middle school. The
pepulation of these classes reflected the ethnic make-up of the school. The
classes met for five, fifty-five minute periods per week for four 9-week marking
periods.

Academically, the students gradepoints varied from below a 1.0 to a 4.0

22

23
on a 4.0 scale. Approximately, 10 %of the students carried 3.5-4.0, 15% carried
3.0-3.4, 30% carried 2.9-2.0, 30% carried 1.9-1.0, 15% carried under 1.0, prior
to taking this class.

Pro-Unit Assessment

A behaviorlstic model dominated my pedagogy, as most American
pedagogy has been dominated in the past In the behavioristic approach to
teaching and Ieaming, the teacher's task consists of providing a set of stimuli
and reinforcements that are likely to get students to emit an appropriate
response. This instructor believes that the behavioristic approach is not
successful in teaching understanding, synthesis and application, and the ability
to use information in new situations. I believe Ieaming is the product of self-
organizatlon and reorganization.

Traditionally, my biology curriculum included units on the scientific
method, basic biochemistry, cells, genetics and heredity, evolution, plants,
animals, microorganisms, human anatomy and physiology, and ecology. Each
of these units included from 4 to 10 chapters in the textbook. Each unit took two
weeks or less to complete. Very few laboratories were conducted. Each unit
may have included one laboratory while in some units only dry labs were
conducted. Furthermore, a whole lot of information was pressed into each unit
There was no connections in these units either. Using the thematic approach to
teaching science gave me more time to connect scientific ideas.

A focus on themes is a fundamental part of a conceptual approach to

24
biology. When I began teaching my unit, my district adopted “Biology:
Principles & Explorations“ by Holt, Rinehart and Winston. This was an
opportunistic time for me to restructure the curriculum and align the curriculum
with a thematic approach to teaching biological principles (laying the foundation
for the study of individual organisms) and biological explorations (studying
individual organisms). Themes are the relationships between ideas and it was
the energy theme I utilized.

We, as educators, need to recognize that learning is a complex process,
and that individual students learn differently. The Ieaming environment I
produced was varied to include different Ieaming styles that students brought to
my class. In providing more opportunities to investigate ideas, the students were
Ieaming to connect what goes on in class with other aspects of their lives. The
investigations encouraged students to look for other examples and applications
of concepts. Several students commented that they liked to work in
the lab rather than work from the book, and they proved this by showing
enthusiasm for each lab I planned. Traditionally, on lab days the students used
to be upset and complain. Laboratories usually meant a formal lab report which
the students did not like to do.

Before teaching the unit, I conducted clinical intenriews with three
students with different academic abilities. A clinical interview is a tool to assess
how students think about the topic they study. This pro-assessment knowledge
enabled me to adjust the curriculum to the needs of the students. A Synopsis of
the results, illustrating the misconceptions, can be found in Figure 1 on page 30.

25

Detailed transcripts from the interviews can be found in Appendix B .

Description of the Clinical Interviews

My central question for the unit was, “How does the energy from the sun
become the energy for life?“ The model answer I expected was: “Energy enters
an ecosystem as plants absorb the sun‘s energy for photosynthesis. This
energy, in the form of radiant solar energy from the sun, is converted into
potential chemical energy by photosynthesis. Energy flows through an
ecosystem as one organism eats another organism. The chemical energy
stored in food is then converted into mechanical and biological energy by the
organisms that eat the food. Energy flows out of an ecosystem, at each trophic
level, as organisms release metabolically generated heat to the surroundings.

To determine student understanding of this concept, I chose three
students of varying academic ability. The students school transcripts were
utilized to determine their academic standing. I found Mary to be an “A“ student,
Justin, a “810“ student, and Rhonda, a “D'I student I began the inte~iews by
emphasizing to the students that this was not a test, and that right or wrong
answers were acceptable. I wanted to know what they knew about energy. I
used a tape recorder to record the interviews. I explained to the students how
and why I would use the tape recordings, and I asked the student‘s permission
to use the data in my research. The students were assured they would remain
anonymous; I would only use first names.

First, I quesfloned the students on forms of energy. “What kinds of energy

26
do you know about? Can you name them?“ I probed for student knowledge on
the general topic energy before I questioned them about specific forms.

lnthe second partofthe interviews, lasked thestudentstotell me how
people get their energy: “What do we use energy for? Do we get energy from
food?“ Then I asked, “How do plants get their energy? When we eat plants do
we get the plant's energy or do we make our own?“

Next, lshowedthestudentsastackofcardswithvariousorganismson
them (See Appendix B). I instructed the students to assume all of the organisms
live together In a biological community and to place them in an order to show
how energy flows through that community. Put sunlight and heat where they
belong and try to include all of the organisms. Then explain why you arranged
the cards as you did. I probed the students further on their ideas about heat and
sunlight as forms of energy and how soil bacteria and mushrooms played a role
in their model.

I concluded the interviews by asking the students to tell me all they knew
about energy. I asked the students if they had questions about energy they

would like to ask me.

What Happened During the Interviews

The first student I interviewed was Mary, the “A“ student Mary is a high-
functionlng, academically advanced ninth grader. She was very willing to
answer the questions and she understood very well that I did not expect the
right answer. Justin, the “BIG“ student, is a slightly above-average ninth grader

27
who also knew I did not expect the right answer. Both of these students had
been participants in clinical interviews previously with other instructors. ldld not
know this prior to the interviews. Rhonda, the “D“ student, is a low-functioning,
below average, tenth grader. She had a hard time understanding why I did not
expect hartogivethe right answer. Asaresult, she responded toseveral ofthe
questions with, “I don‘t know.“ I had to probe her frequently to respond. Her
answers were short and lacked detail.

The interviews began with asking the students to name all of the fame of
energy they knew. The students gave me answers such as food, kinetic energy,
hydroelectricity, nuclear energy, hype behavior, and light bulbs. The students
were defining energy in a misconceived sense. Mary and Rhonda both thought
of energy as vitalism. Mary added that we get energy from the amount of sleep
we get and form nutrients. Justin said we get energy from the food we eat which
comes indirectly from the sun, but he added that metabolism separates and
burns food into energy. The students thought that humans can make their own
energy.

I then asked the students to tell me how plants get their energy. Mary
mentioned the term photosynthesis but, she could not explain the process. She
and Justin thought that plants get their energy from the sun, water, air, soil, and
soil nutrients. Rhonda thought “they got their energy through the roots from the
soil.“ The students considered energy as food. Rhonda thought plants, like
animals, consume food to get their energy.

I gave the students a task to do next. The task involved placing

28
cards, containing organisms that might live together in a biological community,
in an order to show the flow of energy through that community. The results of the
activity were very interesting especially in the response of Rhonda, who did not
include the plants in her community. Her sequence, in one case, went
soil>bacterla>earthworm>Purple Martin. She had no conception that autotrophs
secure the energy required by the entire ecosystem and that this energy is
supplied by the sun. The other two students were cognizant of food chains and
webs. Both Justin and Mary knew that energy flowed from the producers to the
consumers. However, Justin thought that energy was “recycled“ similar to
nutrients.

I asked the students to Include sunlight and heat in their models. All three
students placed sunlight first in the sequence. Mary and Justin knew that plants
needed the sun's energy to photosynthesize. Rhonda, on the other had, did not
even include the plants. One of her sequences showed the sunlight giving
energy to the hawk

Explaining heat was more difficult for all of the students. Mary said
everything has heat in It and gives it off, so heat should be near an organism.
Justin said all animals need heat to survive or their bodies would freeze. He
also said living organisms get the heat they need from sunlight. After some
probing by this instructor, he said that animals produce heat because they burn
energy, and the heat goes off their bodies through “sweating“ and into the air.
Rhonda had no conception of heat energy. She said sunlight gives warmth and
that this was heat

      

.. rt. Vs... .. . ..... . .. . .. .. r n . . . .
. .. . ...........T:; 5... 1: _ t _ _ ___._.. T. ._ s. . _... .35.... ._..r._£_.s...t.fisa,

29

When I asked the students the question,“What is energy used for?“, they
all answered it was needed to live and be active. Justin’s answer was
enlightening. He said, “energy is used during sleep to burn food that is being
digested.“ He also said, “you need energy even to breathe.“ Mary’s answer was
likewise enlightening. She said, “energy had 'weak’ and ’strong’ forms and that
we use the ’strong' toms of energy which come from a lot of nutrients from
metabolism.“

Attheendofthe interview, Iallowedthestudentstotell meanythingelse
they knew about energy. Rhonda said, “nothing.“ Mary said, “she had heard the
term used a lot but never studied it in detail.“ She knew food chains and food
webs involved the “use or energy“ but, she was not sure how everything was
“put together.“ Justin said, “We use energy everyday. We can't live without It It
gives us the strength to wake up.“

Finally, I asked the students if they had any questions to ask me. Mary, as
well as Rhonda said, “no.“ Justin asked me a question about how energy is
stored in solar panels. He appeared to be interested in the practical application
of this concept. I think he needed some concrete evidence of energy usage. I
think the students were all relaxed and did an excellent job with this interview. I
thanked them and sent them back to the class where my lntem teacher from
Michigan State University was conducting the lesson.

30

 

 

 

 

 

 

 

 

 

 

 

 

‘l' ISSUE MARY RHONDA
l. lands of Energy kinetic, hyper solar, hydro food, light-bulb
behavior, electric. food way of acting
nuclear.
to make a
liQt-bulb work
ll. Where does energy from food and irom food. food
come from? amount of what is eaten.
sleep, from from sun
nutrients
lll. How do humans from sleep. metabolism rcst, eating the+
get energy? processing separates and right foods.
nutrients from turns food into get energy
food, make our energy from wmer
own energy A
IV. How do plants get photosynthesis from sun and from soil
energy? from sun, soil, through
water, air soil nutrients. roots, they eat
and sun make like humans
grass
v. How does energy - from sun> like recycling, from sun>
flow through a producers> sun>grass> hawlo
community? consumers animals> mouse>
humans>grass heat ’
VI. How do eco- sunlight at plants need sunlight
systems involve beginning of sunlight-all gives warmth
sunlight and food chain, animals need this is also
heat? everything has heat to survive heat
heat in it and or bodies would
gives it off freeze, get heat
from sun and
burning energy.
heat to air
ll. What is energy every movement can’t live without everything.
used for? and everything we it, use it everyda movement
do. forms of energy gives us we need it
used from metabolisrr to wake up,

 

 

Fugue 1 - Pro-Unit Synopsis of Focus Students’ Understanding

31
Evaluation of Clinical Interviews As An Assessment Strategy

Overall, I felt the interviews were a huge success even though they took
extra time to plan and implement. Knowing the focus students knowledge of
energy, gave me insight to plan for an effective unit which would address the
misconceptions the students appeared to have.

Realistically, I would not be able to do clinical interviews before each
unit. My intern teacher's presence in the classroom gave me the opportunity
and the time to conduct the interviews. I realize it is very difficult to arrange three
separate interviews which last about 20-30 minutes each. As a classroom
teacher, who is given more to teach and less time to teach it each year, I could
not find the time nor “find the energy“ to do clinical interviews for every unit
taught My intent is to develop and conduct clinical interviews for all of the units I

teach, feasibly completing one per year.

Outline of the Unit

The instructional unit in energy was based on chapters 4, 5, and 16-2, of
WW3. by Holt, Rinehart, and Winston, Inc., 1996.
Previously, I took about 2 1i2 weeks to teach the information contained in these
chapters. In general, I spent approximately one week on each chapter so that
wecould reachtheendofthetextbytheend oftheschool year. In this unit,
minimal textbook reading was supplemented by eight laboratory exercises,
several activities and dry laboratories including a model building activity, lecture
notes, overlays, laser disc images, and video tapes. I used a thematic approach

32
to teach less information to insure students had time to construct their own
knowledge. The unit took 29 days to complete (See Appendix A).

To make instruction fruitful, I utilized the data gathered from clinical
interviews conducted before teaching the unit (See appendix B). During the
unit. a variety of pedagogic techniques were utilized to address the different
Ieaming styles of the students. Using overhead transparencies, laser disc
images, video tape presentations, and demonstrations, visual learners were
engaged. Auditory learners were engaged through lecture, class discussion,
and cOOperatlve group work. Tactile, or kinesthetic Ieamers were engaged by
the use of a variety of “hands-on“ activities.

The central question I developed for the unit, “How does energy from the
sun become energy for life?“, was the problem I established at the beginning of
the unit. I hoped that students would see that although they did have important
knowledge and beliefs about this problem, they could not solve this problem
without additional knowledge. Students must learn to use the ideas presenbd
to them to describe, explain, and predict or control the world around them,
individually or in groups.

A gradual transition from mechanical to biological energy studies
allowed students to gain an appreciation of how the principles of science can
be used in both living and non-living systems. The purpose of the 8 laboratory
exercises and the other Ieaming involving manipulation of materials or Ideas
was to provide a Ieaming atmosphere where the students felt comfortable with
scienceandthenewpedagogy.Asynopsisoftheweeklyactivitiescanba

33
found in Figure 2 on page 35. l have indicated all new activities with an asterisk.

Energy, a connecting theme to other scientific concepts provides
students with a framework and comfort level for studying other scientific
concepts. Matter can be discussed before or after the energy unit. I had taught
the concepts of matter, atoms and molecules before the energy unit, but I did
not teach matter cycling until after the unit My goal was to help students
construct their own knowledge of energy by making connections with their real
world lives. Furthermore, I wanted the students to see the connections between
the physical and biological sciences and how science is integrated into their
lives.

Evaluations of student Ieaming and comfort with scientific ideas, included
clinical interviews, student writing, exit evaluations, concept maps, quizzes,
cOOperative Ieaming group reports, laboratory notebooks, and pre- and post-
testing.

Audio-Visual Aids Used

As discussed in the introduction to this unit, the concept of energy is very
difficult for high school students to understand. To make the concept as
interesting and accessible as possible and to help the students understand the
concepts, the unit incorporates use of cartoon overhead transparencies. These
overlays are reproduced in Appendix F.

The book, mm, by M. Hoagland and B. Dodson is a
highly original book that takes you on a guided tour of the many ways all life

34
grows, develops, reproduces itself, and dies. The authors merge science and
art. “The visual presentations encourage the reader to make imaginative leaps
from the panoramic world around us to the world within the cell and back again“
(Hoagland and Dodson, 1995).

The laser disc, “Holt Biology Videodiscs to Accompany Biology:
Principles and Explorations“, provided images and pictures to enhance the
lectures, discussions, and laboratories. I used several images from the laser
disc when the unit addressed photosynthesis, respiration, and fermentation,
particularly.

Student mastery of the concepts of photosynthesis and respiration and
their roles in the flow of energy in an ecosystem was aided through animated
videos. I showed the video tapes, “Energy Flow At the Cellular Level“ (Films For
The Humanities & Sciences), and “Cellular Respiration: Energy For Life“
(Human Relations Media) which went into great detail on these processes.
These details. which were not germane to the unit, confused the students.
Therefore, the next time I use these tapes, I will edit the content and show only
segments of each which are relevant to the “Big Ideas“ of photosynthesis and
respiration.

In the next section, I discuss the laboratories and activities in detail,
including the new pedagogy, and how the new methods affected student

Ieaming.

35

“W

Protest “
Laws of Thermodynamics “
Advertising Campaign “

Bioenergetics Introduced

Overheads from. W

Lab 1-“Thennal Energy From Foods“ “
Video-“Energy Flow At The Cellular Level“ “
Lab 2-“Food Tests“ “

Concept Map of Photosynthesis and Respiration Connections “
Discussion of the Electromagnetic Spectrum and Light
Lab 3-“The Separation of Plant Pigments By Paper

Chromatography“ “

 

Lab 4-“Light and Chlorophyll Laboratory“ “
Discussion of How Heterotrophs Get Energy From Autotrophs
Video-“Cellular Respiration: Energy for Life“ “

Marshmallow Models of Photosynthesis and Respiration “
Lab 5-“Respiration Investigation“ “

 

Lab 6-“Varlations in Carbon Dioxide Production: Using Instant
Blend Dry Yeast “

Discussion of Energy Flow Through An Ecosystem Including
Use of Food Chains, Food Webs, and Energy Pyramids

Lab 7-“Yeast Fermentation“ “

Lab 8-“Bacterlology of Yogurt“ “

Build Ecocolumns “

EssayontheJoumeyofAPhotonOfLightAsltPasses
Through An Ecosystem “

Post Test

Exit Polls “

Figure 2 - Synopsis of Agenda

36
Laboratory Exercises, Demonstrations a Other Activities
The demonstrations, comparing the different kinds of energy in

mechanical systems, started the students asking questions about everyday
energy phenomena. Journal entries (Appendix G), and the Energy
Transformation worksheet (Appendix H), helped to evaluate student
comprehension. A discussion of the Laws of Thermodynamics which followed
preceded the cooperative activity which required the students to use the
everyday phenomena they were aware of to explain two scientific laws. In this
way, the students were constructing new knowledge out of pre-existing notions
about energy in closed systems like the Earth. Some of the posters were hung
outside of the room in the hall for public viewing. Students were proud to see
‘ their work displayed. A quiz, (See Appendix I), showed that students
comprehended the laws of thermodynamics, but still failed to connect these
laws to biological systems. When asked to make posters of the laws, students
commonly used the demonstrations to explain the second law. Fallen pop cans
supposedly are more organized when stacked, but less stable. Vln'ten entropy
(disorder) increases by knocking the cans down, the cans become more stable.
Students were unable to relate this idea to energy in a closed system like an
ecosystem. My goal was to help students realize this relationship by the end of
the unit.

In the first laboratory, “Thermal Energy From Foods“, (Appendix C) the
objective was to show students that food does, In fact, contain potential energy
that is transferred into thennal energy to heat the water. The energy contained

37
in foods is measured in kilocalories or as food labels display “calories“. After
the lab, the students were able to see that the calories some of them count, and
the calories they see on package labels, are the energy units that food contains.
The students brought in and analyzed the energy content of foods by reading
the labels. We discussed that bumlng the food which contains fuel for the body
is very similar to bumlng gasoline In an automobile. I showed the pardon of the
video “Cellular Respiration: Energy for Life“ which compared the human body‘s
use of energy with an automobile's use of energy. The students wrote the
similarities and differences in their journals. (Please refer to Appendix G for a
complete list of journal armies.) This lab was quite successful in showing that
food does contain thermal energy. The students observed and calculated the
energy released by the bumlng of food which did increase the temperature of
the water. The mathematical calculations were difficult for many students to
complete. It became necessary to review examples before they calculated their
results.

The second lab, “Food Tests“, (Appendix C) was designed to build on the
knowledge gained from Laboratory 1 conceming energy in food. This exercise
allowed the students to test known foods and foods they brought from home for
the presence of certain energy containing nutrients such as sugars, starches,
proteins, and fats. Prior to the tests, a thorough discussion of the energy rich
molecules found in food was conducted. This laboratory, together with
Laboratory 1, provided the students with a conceptual model of energy found in
food items as part of the everyday world rather than a concept which cannot be

38
seen but only described in an equation. Evaluation of student Ieaming took
place through laboratory journal entries and a formal laboratory report for the
second laboratory.

These lab reports showed that students understood what the nature of
these indicatorsandtestswere, andthatthese indicatortestscouldba usedto
discover what molecules are present in food. We discussed that the energy we
getfromfood isstored lnthe bonds ofthese molecules. Atthis point, I used are
information in the book by Hoagland and Dodson to show how energy is stored
and transferred in atoms and molecules.

The second cooperative group activity Incorporated the students' prior
knowledge about photosynthesis and respiration. This exercise was intended to
evaluate student understanding of the energy- producing and
energy-consuming processes in both plants and animals. The exercise used
pictures provided to the students, (Appendix D), 11“ x 17“ construction paper,
and glue. in each group, all students had to agree on how to place the pictures
in a concept map design so that the map made sense. This involved some
discussion and consensus on the part of each group. No two maps were
identical, which was helpful when the presentations were made to the class. A
discussion followed after the presentations addressing which group had the
“correct“ map. Ofcoursenoonemapwastheonlyrightanswer.

Students dbcovered that concepts in science can be seen and
comprehended by neighbors in the same community of science differently and
still be acceptable. However, students also found out that scientists have

39
convincing scientific jargon which does explain natural phenomena. After
presenting the maps, we compared them with the textbook ideas to see the
similarities and the differences.

It is evident from the maps that students know that plants need carbon
dioxide, water, and sunlight. It was less evident from the maps that students
knew that sugar and oxygen were the reactants in respiration. Students had
various ideas as to where mushrooms belonged in the map as decomposers.
Chlorophyll was a term they were familiar with, but they did not know that
mushrooms do not have it and cannot photosynthesize. Mushrooms were
considered to be plants by many students. Most of the students did know that
bacteria were decomposers because we had discussed this. However, we did
not discuss mushrooms as decomposers.

The students built models of the processes of photosynthesis and
respiration using colored marshmallows and toothpicks (See Appendix J), to
construct their knowledge of atoms and molecules. After evaluating students'
perceptions about the “big ideas" photosynthesis and respiration, the objective
of Laboratory Three, “The Separation of Plant Pigment by Paper
Chromatography“, and Laboratory Four, “Light and Chlorophyll“, (Appendix C),
was to illustrate the role light energy has in photosynthesis. It was an objective
of the unit to help students realize how plants capture and store the energy from
the sun analogous to solar cells' ability to capture and store the energy from the

sun. Lab Three showed the hidden pigments plants possess to facilitate energy

40
absorption. Prior to this lab, the lecture on light and the demonstration of the
visible light spectrum revisited the characteristics of light, as the subject of light
is taught extensively in eighth grade.

Laboratory Four, “Light and Chlorophyll Laboratory“, was designed to
show the students what colors of visible light are necessary for chlorophyll to
develop and thus photosynthesis to occur in bean seedlings. This laboratory, in
connection with Laboratory Three introduced the concept that radiant energy
(sunlight) is absorbed by autotrophs and it is transferred into chemical energy
used for growth. It was exciting for the students to see the bean seedlings
emerge from the seed coat and actually grow without adding anything to the jar
except sunlight This may have addressed any questions about what plants
need to survive.

Laboratory Four initiated student questions about plant growth and
development. Plant morphology, etc., is discussed in detail later in the year
when diversity of living organisms is addressed. However, a mini lesson on
plants was necessaryforthe unitto proceed andforthe studentsto
conceptualize radiant energy being used for growth and development of plant
tissue. This laboratory took seven to ten days to complete. Unfortunately, some
of the students' data were inconclusive due to the fact that several seeds did not
germinate. I assume this happened because the seeds were old or there was
not enough moisture in the jar. Whatever the reason, some students were
disappointed with their results. However, no activity or experiment should be

considered a waste of time and discarded without discussion. This was an

41
excellent opportunity to discuss how some laboratory exercises do not work out
as planned. The inconclusive results gave the students an opportunity to
analyze and synthesize which are higher order thinking skills. (Bloom, 1956)

In the next lesson, I used a demonstration. I attempted to show that the
“energy“ of molecules is stored in the bonds, and I wanted to demonstrate that
electrons possess energy as a function of their distance from the nucleus of the
atom. A rubber band represented the bond or distance between the electron
and the nucleus of the atom. A flaccid rubber band or an electron close to the
nucleus has little energy. However, if you stretch the rubber band, boost the
electron to a higher energy level (further away from the nucleus), the energy of
the bond is greater. Just let the rubber band hit something in both cases for
effect, preferably not yourself or a student, to emphasize this concept. I wanted
the students to see the energy absorbed by the molecules of chlorophyll gained
energy by being boosted by the photons of light to a higher energy level. I told
the boosting electrons metaphor so the students could visualize the concept I
could tell students were comfortable with the story of the bowlers found in
Appendix K . They could identify that bowling balls falling from higher levels
have more energy and thus can do more damage than those falling from a
lower level. ATP was discussed only in that it is the energy currency of the cell;
the energy being held in the phosphate bonds of the molecule.

Cartoons are a fun way of enabling students to show integration or
application of scientific knowledge. The overlay by Calvin and Hobbes (1990) in
appendix F , was adopted from material I acquired in the Cell and Molecular

42
Biology course at Michigan State University in the summer of 1992, taught by
Dr. Clarence Suelter and Dr. Merle Heidemann. This overlay was very effective
in showing how electrons are transported in the electron transport chain, and
how much energy they possess at each step. The story of photosynthesis,
found in Appendix L, helped especially auditory Ieamers to conceptualize what
happens in each step of photosynthesis without going into detailed facts.

Laboratory Five, “Respiration Investigation“, (Appendix C), showed that
respiration occurs in plants as well as animals, and how the rate of respiration
of seeds can be determined. It is a common misconception of students to
believe that only plants photosynthesize and only animals respire. This lab was
adopted from the Cell and Molecular Biology Class I attended at Michigan State
University, also. The next time I do this lab I may have some students set up the
respirometer using seeds and some others using insects or other small
creatures. This will further address the aforementioned ideas. After measuring
oxygen consumption over time, the students realized that plants do indeed
respire. They were able to see a colored bubble of soap move in a glass tube
as the seeds consumed oxygen, and they were able to quantify how much
oxygen was being consumed.

Fermentation activities concluded the lessons on energy usage in living
organisms. The smallest organisms have a need for energy and with this
energy they are capable of growth and development, movement, and
reproduction, etc. The fermentation Labs made the students aware of how

microorganisms function in their environments, and how they use energy.

43

Laboratory Six, “Variations in Carbon Dioxide Production: Using Instant
Blend Dry Yeast", (Appendix C), introduced the students to the fact that yeasts
use the energy stored in sugar to grow and reproduce and that they give off
carbon dioxide in the process. Laboratory Seven, “Yeast Fermentation“ and
Laboratory Eight, “Bacteriology of Yogurt“, (Appendix C), were especially
successful. Two examples of microorganisms, yeasts in Lab Seven and
bacteria in Lab Eight, were used in food labs to produce familiar food items. The
students were excited to be able to eat their experiments.

One of the last assessment activities was writing a story about, “Your
journey as a photon of light who got absorbed by an autotroph and then eaten
by one or more heterotrophs.“ This writing assignment was difficult for several
students. It required them to use all the information they had leamad about
energy and synthesize the pathway it follows in a particular sequence of steps.
Some students still possessed naive ideas.

Prior to the last writing assignment, the very last concept discussed was
energy in ecosystems. I gave the students notes including definitions of terms
as well as an explanation and examples of food chains, webs, and energy
pyramids (See Appendix M ). The unit utilized a worksheet, (See Appendix N),
to assess student understanding of energy in an ecosystem. After a thorough
discussion of the energy requirements of an ecosystem, the students had to
design an ecocolumn, which is a terrarium made out of two-liter pop bottles

(See Appendix 0). First, the students were to present their designs to the class

44
to get the class approval. Then, in teams of two, they built their ecocolumns and
added biotic and abiotic factors that would sustain the ecosystem. The
ecocolumns were the center of much discussion and interest during the months
following the completion of the unit In fact, during the ecology unit, later in the
year, we used the columns which were still in the classroom. The writing
assignment asked the students to describe the relationships that existed in their
ecocolumns. They included that the original source of energy for the closed
systems was the sun. Several students talked about the ratio of producers to
consumers. Energy transference from the sun to the producers to the
consumers was discussed. The writing samples were used again during the

unit on ecology which followed later in the year.

New Pedagogical Techniques

“Less is More,“ jargon for science education in the 1990's, reflects the
new understanding and concern for scientific literacy in all Americans. In view of
this, I decided to take a major concept and to focus my unit development on
teaching strategies which would provide students with opportunities to construct
the important ideas of science by providing them with fewer content topics
taught in greater depth. It was also my intent to help students see connections
among the sciences and between science and other school subjects. Students
must engage in activities requiring higher order drinking before they learn basic
scientific facts. Students must use scientific knowledge in combination with
other kinds of knowledge about the world.

45

In this unit, I attempted to take “the relativistic conceptual framework
where our thought-world incorporates the conversion of energy principle“, a
very abstract idea, (Elkana, 1974) and make It a framework to build unifying
ideas in science. No minor dead, I might add. To accomplish this task, I
incorporated the constructivist ideas of Ieaming and teaching into this unit to
engage students actively in the construction of new knowledge which would
replace their naive knowledge through a more experiential and laboratory-
based curriculum. The strategies I utilized were chosen to engage students to
actively struggle with ideas rather than simply memorize the facts and “witness
the teacher’s performance“ (Anderson at Roth, 1989).

Writing assignments were used as tools to get students to share, try out,
examine, contrast and revise ideas. Writing stimulated students to clarify and
articulate their positions and ideas. “It helped elicit ideas, contrast these ideas
with those of others, and build onto and change their ideas“ (Roth, 1992).
Writing assignments did not consist of a collection of “neat assignments“
plugged into a science unit, but were connected to the inquiry process. I felt it
was important to create a social context-a Ieaming community of scientific
inquiry-that would enable the “eliciting, challenging, and contrasting to support
students in developing connected, useful, and reflective understandings of
science“ (Roth, ibid.). Writing experiences were connected as closely as
possible to genuine inquiry into what it means to learn, understand and
appreciate science.

Itried to establish a Ieaming-centered classroom rather than a work-

46
setting one, as suggested by Roth (1992), with the activities I designed and
carried out in the classroom (See Appendix P). To shape the Ieaming-centered
classroom, I made use of the 9-patch quilt metaphor articulating Kathy Roth's
ideas about the ideal classroom (See appendix O). I especially liked the part of
the metaphor which described the quilters as “the teachers and the students are
the quilters who work together to put the patches together patiently over time
using consistent tiny stitches." Instead of imparting knowledge and expecting
behavioristic Ieaming, I engaged a curriculum geared toward empowering and
enabling Ieamers to construct their own knowledge using inquiry, questioning,
and collaborating, etc.

In helping the students Ieam, I became a better Ieamer, also. Preparation
of concept maps proved to be a valuable tool in aiding students to acquire self-
knowledge of how they best learn. I used these concept maps to learn how the
students were Ieaming and then I adjusted the lessons according to what I had
learned.

Each day l assessed student mastery of the unit by asking students to tell
me or write down one thing they leamad that day and/or one thing they were
confused about. With these pieces of information I was able to adjust the
curriculum to meet the needs of the students. Students responded positively to
this avenue of assessment because several had questions or did not
understand something yet did not want to ask the questions publicly. Also, I
addressed these concerns right away the next day, so students could have

questions answered on a daily basis. This was a very effective strategy.

CHAPTER 3

CHAPTER 3

EVALUATION

Pro-Test and Post-Test Results

A test administered to the students before the unit was taught and again
at the end of the unit measured student growth in mastery of the concepts
presented in the energy unit (See Appendix R). The pre-test consisted of 26
multiple choice question, 19 true/false questions and 12 flll-ln-the-blank
questions. I attempted to distribute the questions evenly over all of the content
areas taught in the unit, for a total possible 57 points.

No advance notice was given to the 68 students, mixed ninth and tenth
graders, in three different sections of introductory biology, prior to administration
of the pre-test. None of the students had been previously enrolled in a biology
course.

I assured the students that the pre-test would not be used to determine
their grade, but that they should try their best to answer every question. The
students appeared to take the test seriously and completed it in about twenty-
five minutes.

The post-test consisted of the same questions used in the pre-test. It was
administered 28 days after the pre-test at the end of the energy unit. I added

47

48
seven additional short answer questions to test the students ability to analyze,
synthesize, and evaluate the major conceptual ideas presented in the unit. The
students were informed about the post-test in advance. They completed the
post-test in about forty-five minutes.
lpooledthedatafromthethree classesto giveanoverall pictureofthe
increase in knowledge achieved by the 88 students in the study (See Table 1).

mm mm

number of scores (n) 68 68
mean score (x) 14.99 43.26
standard deviation (5) 5.28 8.89
standard deviation 2 (s2) 27.88 79.03
standard error of mean (sx) 0.64 1.08
standard error of difference (sx-y) 1.26
difference between means (x-y) 28.27
degrees of freedom (df) 134

t 22.44

Table1 - Pre- and Post Test Pooled Data of All Classes

49
The mean score on the pre-test was 14.99 which rose amazingly to 43.26 on
the post-test. The standard deviation for the pre-test was 5.28, while that on the
post-test was 8.89. The standard error of the mean for the pre-test was 0.84
while that on the post-test was 1.08. In comparing the pre- and post-test results,
I found the standard error of difference to be 1.26. The t value was 22.44 with
134 degrees of freedom. The probability of these two sets of scores being
different merely due to chance was less than 0.1% allowing me to reject the null
hypothesis that the students did not show growth on the mean score. It is clear
that students had shown growth on the mean score of the test

The post-test constructed response section (Questions 58-64), allowed
me to further assess student comprehension of energy principles. Responses to
questions 58 and 59 showed that students were able to explain the relationship
between photosynthesis and respiration. About 25% of the students wrote
proper equations regarding photosynthesis and respiration and showed with a
circular diagram how the atoms are shared and where energy is transferred.
They were also capable of explaining their diagrams.

Almost all of the students knew that plants photosynthesize and respire
and that animals use the food of the plant to get their energy through
respiration. In 33% of the responses, a seed was pictured taking in oxygen and
letting out carbon dioxide which was shown being taken up by a plant. The
plant then was shown giving off oxygen to an animal that was eating it The
animal, was shown giving off carbon dioxide to the seed. Ninety-five percent of
the students understood that sunlight is the ultimate source of energy for plants

50

and animals. Several students wrote what I had hoped for, that plants need
energy from the sun in combination with other ingredients to photosynthesize.

Answers to question 60 showed that 62 of the 68 students had learned a
basic characteristic of light: the color we see is the color being reflected by the
object. Approximately 75% of them knew about the other colors plants display
and that chlorophyll has different potentials for absorbing the energy from
photons. All of the students knew that a pigment was responsible for
energy absorption, though 69% did not name the pigment chlorophyll.

Question number 61 asked students to diagram “energy“ relationships
among organisms. All of the students showed energy coming from the sun
going to the producers, and then to the consumers. Heat was shown coming off
the last organism in the chain. Very few students (3%) showed heat energy
coming from all organisms. Perhaps this was due to the way food chains and
food webs were addressed during the unit Only 28% of the students knew
where mushrooms fit in the diagram. We had not talked about fungus as
decomposers prior to the energy unit Most of the students-thought that
mushrooms were producers. Eighty-two percent knew where soil bacteria fit in
as decomposers. The students were familiar with bacteria because we had
discussed them in the unit. Eighty-six percent of the students drew food webs
and 25% drew food chains. Of the 25%, 20% put more than one organism at
each level of their diagrams similar to the concept maps they had produced.
Eighty-seven percent of the students used arrows to show the direction of

energy flow with 78% of them pointing the arrow in the correct direction of

51
energy consumption. Those not using arrows drew lines or put similar
organisms together in a group.

Questions number 62 and number 63 asked students about sources of
energy for humans and the human food supply. One hundred percent of the
students chose at least one food item, 78% chose at least two of the food Items
and 33% chose all three food items, milk, hamburger, and sugar as sources of
energy. Fifteen percent of the students marked minerals and water as
necessary sources of energy. Only two students marked sunlight striking the
skin as a source of energy. Students know humans cannot use the energy from
the sun like autotrophs can. Without transference of the sun's energy into the
tissue of plants, higher organisms, such as humans, could not exist

In answers to questions 63 and 64, the majority of the students explained
that without grasses several consumers, that consume grasses and the by-
products of grasses, would perish. Eighty-three percent said we would not have
pork chops or roast beef. A smaller percentage, 61%, also included the animal
by-products eggs and cheese. Ninety-two percent said that the other autotrophs
would not be affected. Eight percent knew without grasses, all organisms would
be affected.

Ninety percent of the students knew instructing an over-populated
country to feed its people beef rather than vegetables was not good advice.
They showed through an energy pyramid how less energy is available at each
trophic level.

The responses to the questions in this section of the test indicated that

52
students were able to apply what they had leamad in the unit by constructing
adequate answers. I was pleased to see the students' ability to apply the

knowledge they had acquired to new situations.

New Teaching Strategies

It was clearly evident that the students enjoyed themselves during this
unit. My enthusiasm affected the overall feeling of the classes. In teaching less,
not only did I better understand what I wanted students to understand, but the
students found it more enjoyable to memorize less and understand more.

By abandoning the traditional approaches and instead focussing on key
concepts of energy use of organisms student understanding improved as
evidenced in the post test results. Eight laboratories were conducted during this
unit. The subjective performance assessments showed an increased maturity
level of the students in the lab. Product assessments showed that the students
were actively questioning scientific concepts and journal entries showed they
were pursuing investigative options. Less intimidating information meant an
opportunity for the students to enjoy themselves while Ieaming useful scientific
knowledge.

I measured student comfort in science with exit polls. I asked students to
write down any thoughts they had after the unit was complete. I was surprised to
find approximately ninety-five percent of the students had at least one positive
thought about the unit. The flve percent who were quite negative were either

attendance or behavior problems.

53

Writing, for most students, was not easy. I believe this was due to a lack
of experience in writing in a science course. Journal writing was a very valuable
tool in stimulating students to clarify and articulate their positions and ideas. I
did not find the exact set of assignments to produce “nice, neat assignments“.
However, I made an attempt to encourage students to write their thoughts and
ideas, challenge them, then change them if they needed to be altered due to
new knowledge. It was encouraging to see the gradual change from students
reluctant to write, writing one sentence entries, to students enthused to write
several paragraphs. In the exit polls, many students found the journal to be
worthwhile and suggested it be used more often. One student commented, “
This journal writing is easy and fun. I wish we could get an assignment
everyday to put in it.“ This obliging attitude may have resulted because of the
assessment strategy this instructor used. I did not grade on quantity or
precision. Each entry counted equally. The journal represented a large fraction
of their grade, 20%. Students came to know how and why they were doing an
assignment. I watched writing assignments progress from two minute activities
into ten minutes and longer. This data is evidence that the students
contemplated the journal writings seriously . Forty-five percent of the students
received an “A“, 39% received a “B“, 10% received a “C“, 4% received a “D“,
and 2% did not turn a journal into me.

Concepts maps were a useful fool for assessing students' prior
knowledge. This strategy was the most difficult for students to grasp. With so
many options for connecting ideas, students were distressed over providing the

54
“right“ answer and organizing infonnation in a way which made sense to them. It
was inspiring to see the groups change the maps as each person contributed
his/her ideas. The scene reminded me of a group of scientists all seemingly
convinced their way is the right way until the next person presents the ideas in a
different, yet, sensible way.

Students considered working in groups very beneficial to Ieaming, and
most felt comfortable, as many wrote this in their journals and suggested this in
their conversations:

“I wish we could work in groups everyday.“

“Working with others helps me to understand the material better.“

“Two or three heads are better than one. We should work in groups to

help us learn.“

“What I may not know, another student In the group may know.“

When students work together on a project, they learn in a more productive
atmosphere. Subjective evidence and observational data I gathered pointed to
the beneficial effects of cooperative activities on the personal and social growth
of the students. As the teams leamad science together, they also leamad the
importance of trusting and working with people of various backgrounds.

Student Interviews

The clinical interviews took extra time, but were hugely successful in
Ieaming about students misconceptions. Armed with the evidence in
appendix B, my teaching strategies were altered to address the misconceptions

55
students had. Knowing where the students were gave me insight into how I
would get them to where I wanted them to be. In the next section, I present an
evaluation of the pro-unit interviews.

The students were able to name some, but not all, kinds of energy. They
confused different forms of energy with sources of energy. They thought energy
was stored in food like a material and that it may be associated with vitality.
They did not consider biochemical and mechanical energy, or heat in their
answers.

Photosynthesis and metabolism were brought up in the interviews as
ways plants and animals, respectively, get their energy. Plants metabolize, also.
This information was not evident in the responses. The students were not clear
on how photosynthesis or metabolism are related to energy. Photosynthesis
was defined as a plant’s method for using air, water, soil, and sun to make its
own food. Metabolism was defined by the students as a way animals get energy
from food. There was no mention of respiration. However, Justin reported that
body heat comes from burning energy. Energy, as defined by Justin, must be a
material. Mary considered energy to be closely linked with amount of nutrients.
Rhonda thought energy was food. She connected energy to the kinds of food
we eat. For example, she said we were able to get more energy from lettuce
than hamburger because it was healthier. Not one of the students discussed
forms or conversions of energy.

The students were able to show food chain relationships between
producers and consumers, but they had difficulty with the idea of the

56 ‘
decomposers. Rhonda failed to include producers as well as the decomposers
in her responses. They understood energy as flowing through a community and
being recyded. Expanding heat energy into the environment was not
discussed. 1 do not believe the students thought about energy conversions
when one organism consumes another.
Possessing this knowledge of student understanding of energy, I was

able to plan an appropriate unit to address these misconceptions.

CHAPTER 4

CHAPTER 4

DISCUSSION AND CONCLUSIONS

Aspects of the Unit Which Were Effective

The goals of the unit were to help students construct their own
conceptual understanding of energy and to feel comfortable with science.
These goals were implemented by utilizing a thematic approach with a
constructivist philosophy, additional “hands-on“ activities, and written product
based assessments including essays, journals, and a formal laboratory report.
An additional goal was to present energy in a way that showed the relationships
between the physical and biological concepts of energy. After discussing
energy in physical systems, I wanted the students to incorporate these concepts
into constructing knowledge about biological systems.

Writing assignments and journal entries demonstrated the effectiveness
of this methodology in helping the students feel comfortable with the concept of
energy. The product assessments displayed that the students were able to
construct and integrate their ideas and show their understanding. This method
of assessment provided for collaborative reflection by both this instructor and
the students. Over the course of the unit, student to student and student to
teacher conversations showed me that students preferred these assessments

57

58

over the traditional selected response format

Informal evaluation of student journals and the post-test results indicated
the laboratories were very effective in accomplishing the goals of the unit The
students' favorite labs were those using the microorganisms’ utilization of
energy to make yogurt and root beer. Many exclaimed that they were going to
try these experiments at home so parents and friends could taste the results. To
take a scientific concept and to see Its worth In everyday life helped to
accomplish the goal of addressing student comfort with science; making the
concept personally meaningful. Testing food for energy containing molecules
was the next favored activity. Bringing food from home for testing was a
popular, worthwhile activity. This activity displayed that students were taking
ownership of their Ieaming. Students wanted to pursue calorie content of food
and how calories represent energy found in food molecules. We did not get into
the mathematical details of calories. Perhaps in the revision of this unit, I will
consider this. I

The writing assignments were used as tools to get students to ask
questions on paper as well as to share, examine, contrast, and revise their
ideas. The writing enabled me to better understand each student’s thinking.
Monitoring student understanding through journal entries was a powerful tool
enabling students to communicate their understanding to me. Writing stimulated
students to clarify and articulate their positions and ideas. Through the students’
writing about their ideas, I was able to plan whole class interactions that were
conducive to student thinking. The post test constructed response questions,

59
answered with complete, thoughtful answers, showed an understanding and
appreciation for writing in science to articulate ideas.

Although the students were presented with less facts and details in the
teaching of this unit, they showed an understanding for energy in both
biological and physical systems represented in product and performance
assessments. The advertisement campaign for the Laws of Thermodynamics
and the concept mapping enabled the students to take scientific laws and make
them germane to their own understanding and knowledge about the world
around them.

Other methodologies also were effective in meeting the goals of this unit.
Working in cooperative groups, to develop a final product which was accepted
by the others, proved to be an excellent tool for utilizing everyday contexts in a
Ieaming-centered classroom. Students were encouraged to use ideas from
their classmates. Everyone's ideas were valued and respected as useful in the
Ieaming process.

Concept mapping, also performed in groups, was less effective in making
students feel comfortable with new concepts. However, this tool was helpful for
constructing knowledge. I believe the student discontent with concept making
was a direct result of this instructor's own uneasiness with this assessment tool.
It is my intent to work with concept maps for the teaching of each unit so that I
will feel comfortable and competent In using this tool.

The formal laboratory report required students to use the scientific
method to justify conclusions. The High School Proficiency test in Michigan

6O
utilizes the lab format I required the students to use. The goal of exposing
students to formal science writing was a hidden agenda in this unit. I wanted
students, utilizing the constructivist idea, in part, to experience scientific vwiting
close to their own discourse.

Visual Ieamers showed great enthusiasm for the cartoons and graphic
representations. A difficult concept like energy transference between atoms and
molecules was simply taught using characters to represent the atoms. The
cartoons were good stimuli for the writing assignment; “In your journals write a
story about your life as a photon of light and your travels through an ecosystem
as energy that changes form“, found in Appendix G.

Finally, exit evaluations indicated student comfort was high during this
unit. I have never before asked students to evaluate a unit. After students
realized these were not quizzes and would not be graded, the questions and
ideas flowed onto the paper. I was able to assess student mastery of the
concepts in this unit as well as any lack of understanding. These evaluations

were private acclamations of comfort and understanding.

Aspects of the Unit Needing Improvement

l was not successful in providing a Ieaming-centered classroom as
described by Kathy Roth (Appendix P ). I still feel that the students simply valued
“getting the right answer“ and felt that Ieaming was a private activity for
completing the projects and other assignments. I believe “getting the work

61
done“ was the goal rather than “sense-making and Ieaming“ as the goal. I think
students enjoyed science class because I was enthusiastic, cared about
the students' Ieaming, and had lots of activities to do. Kathy Roth expresses her
concerns in the same way. We do not believe they became experts of making
sense out of the natural world due to the methodologies used. My lack of
experience and understanding of the Ieaming-centered classroom may have
contributed to this result

I do not believe concept mapping, using cutting and pasting techniques,
was a successful assessment tool. Since gluing parts in the concept maps
restricts the alteration of ideas, I will leave them loose so first students could
revisit the map for reexamination and alteration. A felt board, or an erasable
board, would have worked nicely to accomplish this objective. Concept maps
should be an integral part of instruction, providing a process for the instructor
and students to use to guide Ieaming.

Another short-coming of the unit was failure to analyze in depth the
diversity of discourses students brought with them prior to the unit Ethnic
diversity was evident in the students social interactions. As an instructor, I need
to become more empathetic to these differences, and to tailor my instruction to
these differences. It will be my goal in future units to focus on issues of cultural
and social class differences in reasoning. I will make a special effort to help
students use their different discourses and language to become scientifically

literate.

62
Overall Evaluation and Conclusion

In conclusion, the energy unit was successful in reaching the goals I set
for the unit. Students were enthusiastic Ieamers who constructed their own
knowledge of energy. The thematic approach to teaching science breaks up the
content necessary for introductory biology students into manageable units with
connecting ideas. I am convinced that educators, Including this instructor, do
need to teach less detailed scientific jargon and to teach connected scientific
ideas that students can translate into their own discourses. Meaningful lessons
which address everyday natural phenomena must be developed for each
theme in biology. This unit is the first unit in a series I will attempt to develop for
other themes in biology, i.e., evolution, matter, diversity, etc.

The Michigan State Legislature is proposing to require all students to
take three years of science instead of the current requirement of two years. This
would facilitate and encourage a thematic approach to teaching science as
principles or “big ideas“ in the first year, and exploring, in more detail, aspects of
tlrese principles In another year. Although this unit took twenty-nine days to
complete, It Is my understanding that the Michigan State Legislature plans to
extend the school year and with carefully planned units all of the objectives

proposed by MEGOSE can be taught in an introductory biology course.

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Portsmouth, NH, Heinemann.

 

Roth, K.J. (1992). It: - ' . ' - :
(Elementary Subjects Center Series No.56), E. Lansing, MI: Michigan State
University, Elementary subjects Center.

Roth KJ and Anderson C W (1985) WWW;
Institute for Research on Teaching, Michigan State University, East Lansing, MI.

Simpson, M. (1983). The mole cell rules, O.K.?, Aberdeen College of Education,
Biology Newsletter 42: 7-11.

Simpson, M. and Arnold, B. (1982). Availability of prerequisite concepts for
Ieaming biology at certificate level, Journal of Biological Education, 16(1); 65-
72.

Smith, E.L. and Anderson, C.W. (1984). Plants as producers: a case study of
elementary science teaching, Journal of Research in Science Teaching, 21 (7):
685-98.

Solomon, J. (1983). Messy, contradictory, and obstinately persistent: a study of
children’s out of school ideas about energy. School Science Review, 65(231):
225-33.

Webb, P. and Boltt, G. (1990). Food chain to food web: a natural progression?,
Journal of Biological Education, 24(3): 187-90.

Yager, R.E. (1991).The Constructivist Learning Model: Towards Real Reform in
Science Education, The Science Teacher, 52-57.

APPENDICES

APPENDIX A

DAY 1

DAY 2

DAY 3

DAY 4

DAY 5

DAY 6

DAY 7

DAY 8

DAY 9

DAY 10

APPENDIX A

DAILY LOG OF ACTIVITIES

Pretest, 57 questions, found in appendix R,
Overview of energy unit,
Writing assessment in joumais, found in Appendix G.

Writing assessment in journal, found in Appendix G,
Introduction to energy transformations in mechanical systems,
kinds of energy, sources of energy,

Demonstration and worksheet found in Appendix H.

Discussion of the Laws of Thermodynamics, and entropy,
Joumai Entry found in Appendix G.

Cooperative activity-groups work to prepare an advertising
campaign for the Laws of Thermodynamics

Completion of cooperative activity and presentations, small group
discussion of presentations.

Introduction to bioenergetics with lecture,
Journal Entry found in appendix G.

Laboratory Activity 1: W(APPOMIX 0).
Discussion of calories found in food, and on food labels.

Discuss Laboratory results and food labels,
Video: “Energy Flow At The Cellular Level”.

Discussion of ATP (energy currency of the cell),
Lecture notes found in Appendix G.

Lecture on major nutrients found in food (Notes found in Appendix
G),

Preparation for Laboratory Activity 2,

Begin Laboratory 2: Emdlesfinguwpendix C).

66

DAY

DAY

DAY

DAY

DAY

DAY

DAY

DAY

DAY

DAY
DAY
DAY

11

12

13

14

15

16

17

18

19

20
21
22

67

Finish Laboratory and prepare for Formal Laboratory Reports.
Discussion of Laboratory Activity 2 results.

Assessment of student understanding with a quiz (Appendix I).

Introduction to the “big ideas”, Photosynthesis and Respiration
(Appendix G),

Cooperative group activity to create a concept map using pictures
and words provided for the 'big ideas” (Appendix D).

Presentation of cooperative group’s activity concept map from
previousday (Appendix J),
Discussion of results

Introduction to photosynthesis and role of chlorophyll,
Photosynthesis Story (found in Appendix M),

Laboratory Activity 3: W(Appendix C).

Laser Disc Images

Discussion/lecture on characteristics of light,
“Boosting electrons” analogy (Appendix L),
Overlay of photo system (Appendix F),

Laboratory ACUVIIY 4: WMPDGMIX 0)-

Discuss results of chromatography laboratory
Continue observations of Laboratory 4 for 1-2 weeks.

Video: ‘Cellular Respiration: Energy For Life”,
Preparation for project,
Discuss chemical equations for photosynthesis and respiration.

Build marshmallow models of photosynthesis and respiration
(Appendix K).

Laboratory Activity 5: Wlwpondix C)-
Continue Laboratory 5.

Discuss Results of Laboratory 5,
Discussion/ Lecture on fermentation and
microorganismsMppendix E) Conduct Laboratory Activity 6:

 

least (Appendix C)

DAY

DAY

DAY

DAY

DAY

DAY

DAY

23

24

26

27

26

68

Conduct Laboratory 7zm§1£emgmaanAppendix C),
Discuss the results of laboratory 6.

Conduct Laboratory 8: Wm Mimi.
Discuss the results of Laboratory 6 and 7.

Yogurt eating,

introduction to energy flow through an ecosystem with discussion
of food chains and food webs, and energy pyramids,

Notes found in appendix N,

Pyramid of Energy Worksheet (Appendix 0).

Writing assessment, found in Appendix G,
Initial planning for self-sufficient ecosystem.

Build Eco-columns (Appendix P),
Discuss energy flow through these ecosystems in the Ecocolumns.

Discuss results of Laboratory 4,
Preparation for Post Test (Appendix S) .

Post Test and exit poll.

APPENDIX D

APPENDIX B

rnlursotun' or txrnnvmw was an!
(on. stuns)

KINDS OF ENERGY

l- What kinds of energy do you know about?

M-My parents tell me I have too much energy and that I am too hyper. I guess
not being tired. Kinetic energy,k and that energy is used in everything.

l-Can you name any kinds of energy?

M-Kinetlc, Hyper people, nuclear and radioactive, energy to make light bulbs
work.

WHERE DOES ENERGY COME FROM?

l-Where do you get your energy?

M-From food and the amount of sleep you get. The body uses the nutrients for
energy. You need sleep to rejuvenate-Do you know how that works?

M-l don't know.

HOW DO HUMANS GET ENERGY?

l-Where do you get your energy?

M-From food and the amount of sleep.

l-What do we use energy for?

M-Every movement and everything we do. There are strong forms of energy, but
lam not sure what you call this form.

I-How do we get energy from food?

M-Metabolism does this. i am not sure of the connection, but processes the
nutrients and gives us energy.

HOW DO PLANTS GET ENERGY?

l-How do plants get energy?

M-photosynthesis. Plants get energy from the sun, water and air.

l-When we eat a plant do we get energy from the plant?

M-We eat the plant and make our own energy. The body processes the energy
from the plant.

69

70

HOW DOES ENERGY FLOW THROUGH A BIOLOGICAL
COMMUNITY?

l-On these cards I have written the name of an organism. All of these organisms
live together in a biological community. Arrange these cards to show the flow of
energy through this community. Then I will ask you to explain why you put them
in the order you did.

l-Mary can you explain why you arranged the cards in that sequence?

M-Well grass is a producer and so is the tree so I put them first. Soil bacteria
and mushrooms are not predators so they go here, too. The earthworm gets
energy from nutrients in the soil. The bird eats the earthwonn. The coyote preys
on the bird and gets energy from nutrients in the bird. It processes the energy.
Hawk eats sick mouse; it won't get a lot of energy. It will get more energy from a
healthy mouse. Not much eats the hawk. Not much energy comes from a small
organism. A lot of things get energy from the grass. We eat things that get
energy from grass.

HOW DOES AN ECOSYSTEM INVOLVE SUNLIGHT AND HEAT?

l-lnciude sunlight and heat in your diagram.

M-Sun is at the very beginning before grass. Heat i’m not sure about. It is
connected with the deer and coyote because they need it to maintain heat in
themselves. They get help from the things they eat. Energy is created from other
energies.

i-What other organisms give off heat?

M-Any living organism gives off heat Everything has heat in it/ It is body
temperature which is 98.6 in humans.

WHAT IS ENERGY USED FOR?

l-So Mary what is energy used for?

M-For every movement and everything we do. Strong forms of energy are used
from metabolism and a lot of nutrients.

l-Do you have any questions you would like to ask me?

M-No. I don't think so.

71

APPENDIX B

TRANSCRIPT OP INTERVIEW WITH JUSTIN [91:]: GRADE)
KINDS OF ENERGY

l-What kinds of energy do you know about?
J-solar, hydro, electric, food energy.

l-Food has energy In it?
J-Yup...carbohydrates.

WHERE DOES ENERGY COME FROM?

l-Does food need the sun for energy?

J-it needs sun to grow so we can eat it and get energy from what's inside food.
l-Does a hamburger get its energy from the sun?

J-No. Hamburger comes from cows, cows eat grass, and grass came from the

sun and soil. The cow did not get energy from the sun. The cow had to eat the

grass.

I-Where does the energy in the food we eat originally come from?

J-lt comes from the sun and goes to grass and the rest of the food chain.

HOW DO HUMANS GET ENERGY?

I-How do we get energy from the hamburger?

J-When we eat it, metabolism separates and turns food into energy we need.
i-Do we use energy when we are sleeping?

J-Probably. The body is burning food that is being digested while you're
breathing and stuff while you’re sleepin.

l-How does the body turn food into energy?

J-I don‘t really know. Metabolism has something to do with cells.

l-Do you know what metabolism is?

J-lt tums food we eat into energy we can use. Our bodies burn energy.

HOW DO PLANTS GET ENERGY?

Hi we eat to get energy. How do think plants get their energy?
J-They live off nutrients in the soil. They use light, water and air to get energy.
Sun, soil, and soil nutrients make plants.

HOW DOES ENERGY FLOW THROUGH A COMMUNITY?

l-l have a stack of cards with living organisms on them. All of these organisms
live together in a biological community. I want you to arrange the cards in the
sequence you believe they should go to show the flow of energy through this
ecosystem. I will ask you to explain why you put the cards in that sequence

72
when you are done.

I-Explain what you have done, please.

J-Well, the soil bacteria are eaten by the mushroom which is eaten by a frog.
The earthworm eats soil bacteria. Bird eats earthworm. Hawk eats mouse.
Mosquito and insects eat dead organisms. They suck their blood and stuff. The
White cedar is living off the nutrients in the grass because soil, light, and water
give the energy to the grass.

l-What else can you tell me about food chains?

J-Sun hits grass, other animals eat grass, we eat parts of the animals and when
we die our bodies are retumed to the soil-soil nutrients and sun make grass so
it is like recycling.

HOW DO ECOSYSTEMS INVOLVE SUNLIGHT AND HEAT?

l-Where would you put the sun in your sequence?

J-With the grass and cedar tree because they are plants and need sunlight
White cedar is also used as a home for birds and animals.

l-Where would you put heat? You can use it more than once.

J-By the deer, coyote, hawk. They all need heat to live. Their bodies would
freeze.

l-Where do they get heat?

J-They get it from sunlight

l-What happens when you exercise?

J-We build body heat.

l-Why? Where does this body heat come from?

J-Buming energy. Energy makes the body warm by doing exercise.
l-Where does the heat go?

J-Through he body, sweat, and goes into the air.

WHAT IS ENERGY USED FOR?

l-What do we use energy for?

J-We use energy everyday for everything. We can't live without energy. We
need it for strength and to be healthy.

l-do you have any questions about energy?

J-How does solar energy go through those panels and turn Into regular energy?
NOTE: I discussed the answer with Justin, but will not include the conversation
here.

73
APPENDIX B

TRANSCRIPT OP INTERVIEW WITH RHONDA (10th
GRADE)

KINDS OF ENERGY

I-Name the kinds of energy you know about.
R-Electrlclty and food I guess.

WHERE DOES ENERGY COME FROM?
l-Rhonda do you know where energy comes from?
R-Food. i don’t know.

HOW DO HUMANS GET ENERGY?

I-Where do you get your energy?

R-From sleeping and eating health.

l-Would you get more energy from a hamburger or lettuce?
R-Lettuce i guess.

l-why lettuce?

R-Because it is healthier and better for you.

l-Do you use energy when you are sleeping?

R-Yeh, I guess.

HOW DO PLANTS GET ENERGY?

l-Do plants need energy?

R-Yeh, lguess.

l-How do plants get their energy?

R-l guess through the soil, through their roots.

l-Is water energy for the plant?

R-Yes. It keeps the plant alive.

l-Can water give humans energy?

R-Yeh, You have to drink water to stay healthy and get energy.

HOW DOES ENERGY FLOW THROUGH A COMMUNITY?

I-Rhonda, l have a stack of cards with pictures of living organisms on them.
These organisms live together in a community. I would like you to put them in
the order you believe they should be in to show how energy flows through this
system. I will ask you to explain your answer when you are done.

R-I think they go like this, hawk-mouse. l’m not sure what to do. Is this right?
l-You’re doing fine. Keep going.

R-Soil bacteria is eaten by plants I think.

74

l-Where would the other organisms go?
R-l don't know.

HOW DO ECOSYSTEMS INVOLVE SUNLIGHT AND HEAT?

l-Can you add sunlight to your diagram? Where would the sun go in your
sequence?

R-Sun goes in the beginning.

l-Why did you put me sun at the beginning?

R-We need the sun to live. Everything needs the sun to live. We have to have
the sun to stay warm.

l-Where would you put heat in your sequence?

R-At the end.

I-Would heat go anywhere else?

R-I don't know.

WHAT IS ENERGY USED FOR?

l-What is energy used for?

R-Everything. So need it for everything.
I-Do plants also need it for everything?
R-Yup, I guess.

I-Do you know anything else about energy?
R-No.

l-Do you have any questions for me? R-No.

THE ORGANISDIS POUND ON THE STACK OP 3X! CARDS

INCLUDED:
GRASS BAT
EARTHWORM MOUSE
FROG HAWK
SOIL BACTERIA DEER
COYOTE WHITE CEDAR
MUSHROOM PURPLE MARTIN

MOSQUITO

APPENDIX C

APPENDIX C
Laboratory 1

THERMAL ENERGY PRO“ FOODS

Wm: You use food as a fuel for your body. Food contains the stored
energy you need to run, talk, think and even to sleep. In order to survive, your
body must be able to digest the nutrients in food and get energy to keep your
body processes going.

You can indirectly measure the energy contained in a sample of
food. Most of the thermal energy produced by burning the food can be absorbed
by a known mass of water. You must measure the temperature change in the
water. It requires 4.184 joules, J, of energy to raise the temperature of each
gram of water one Celsius degree. This value is the specific heat of the water.
Use the following equation to determine the energy released, 0, when a food
sample is burned.

energy released = temperature x mass x specific heat of water

Q=(Tr-Tr)xmep

mm: You will calculate a change in thermal energy. You will account for
the difference between energy released and energy absorbed.

mm: (Per Group) large paper clips or long pins
matches graduated cylinder (100 mL)
wood splints food samples
ring stand goggles
thermometer
watch or clock
water
aluminum potpie pan
balance
clamp, utility
flask (100 mL or 250 mL)

Mm: 1) Straighten a paper clip. insert the paper clip through the food
sample. Position the paper clip on the edges of the aluminum pot pie pan. Use
the balance to determine the mass of the pan, paper clip, and food sample.
Record this mass in Data Table 1 as m1.
2) Use a graduated cylinder to add 50 mL of water to the flask.
Clamp the flask on the ring stand about 5 cm above the tabletop. Use the
thermometer to measure the temperature of the water, (Tr). Record the value in
Data Table 1.
75

76

3) ignite the wooden splint with a match. CAUTION: always use
care with fire. Use the burning splint to ignite the food sample. Once the food
sample is burning, safely extinguish the splint. Position the aluminum pan under
the flask. The water in the flask should absorb most of the energy given off by

the bumlng food.
4) Carefully stir the water with the thermometer and closely

observe the temperature rise.
5) Blow out the flame of the burning food after about 2 minutes.
Record the highest temperature of the water during the 2 minutes in Data Table

1 as Tr.
6) Allow the aluminum pan and its contents to cool. Determine the

mass of the pan and contents after the release of energy. Record this value as
mz in Data Table 1.

W:

TABLE 1
Mass (9) Temperature ( C)
m1 m2 Ti Tr
Food Sample

Calculate the rise in the water’s temperature by subtracting Tr from

Tr.

Use the equation given in the introduction to calculate the energy absorbed by
water when your food sample burned for about 2 minutes. For the mass, be sure
to use the mass of the water.

 

Q:

 

Make a class data table using the whole class data , all food samples, and the
heat absorbed J/g.

W: Answer the following questions in complete sentences in a
paragraph.

1. Did you measure a temperature change in the water or the food sample?
2. Did you measure the energy released by the food sample or the energy
gained by the water?

3. Most of the energy flowing from the bumlng food is absorbed by the water.
What do you think happens to the small amount of energy that is not absorbed
by the water.

4. How can you calculate the mass of food burned to form a gas or water?

5. What is the mass of food burned to form a gas or water?

6. Suppose 20.0 g of your food sample burned completely with a temperature
rise of 30.0 C. Use a proportion to calculate the value of energy released.

Q:

 

77

7. Look at the data table of different food samples you class tested. Which food
sample released the most energy?

8. In order to calculate the amount of energy released or absorbed by a
substance, what information do you need?

78
APPENDIX C
Laboratory 2

FOOD TESTS

WEI!!!

Recipes for solutions:
Corn Starch Solution (1%)
1 gofcomstarchwlthsmallamountofcoldwater
Mix
Add water to volume of 100 mL
Heat to boiling-boil 1 min. (until starch dissolved)

Sugar Solution (1%)
1 9 glucose (dextrose) in small amount of water
Mix
Add water to volume of 100 mL

Gelatin Solution (1%)
1 g unflavored gelatin In small amount of water
Mix
Add water to volume of 100 mL
Heat solution to dissolve gelatin

Iodine solution may be purchased from most chemical supply companies
as Lugol’s iodine solution or you may obtain tincture of iodine from the local
pharmacy. These solutions should be diluted by adding one part of the iodine
solution with 5 parts of water. if you wish to make your own, dissolve 2 grams of
potassium iodide (Ki) in 100 mL of water. Add 1 gram of iodine crystals and stir
until dissolved.

Iodine changes to blue-black color in the presence of starch. By
comparing the color of the control with the color produced when adding the
iodine solution to each of the nutrients, students will discover which of these
nutrients changes color with the iodine solution. They will then use this
information to test other foods to see if starch is present.

Benedict’s solution may be purchased from most chemical supply
companies. If you wish to make your own, dissolve 173 grams of sodium (or
potassium) citrate (C5I‘I5N8307) and 100 grams of anhydrous sodium carbonate
(NazCOa),in 800 mL of water. (Note: Instead of anhydrous sodium carbonate,
you may use 200 grams of hydrated (crystalline) sodium carbonate. Heat the
solution gently to speed dissolving. Filter the solution. Stir constantly while
adding to this solution, 7.3 grams copper (ll) sulfate pentahydrate (CuSO45H20)

79

which has been 1dissolved in 100 mL of water. Add enough water to bring the
total volume to 1 liter.

Some sugars, called reducing sugars, will react when heated with
Benedict's solution to produce colors ranging from yellow-green to red-orange.

Biuret solution may be purchased from most chemical supply companies
or you make you own. Dissolve 3 grams of copper sulfate (CuSO4 5H20) and
12 grams of potassium sodium tartrate (KNaC4H405; also called Rochelle salt)
in 1 liter of water. Next prepare a second solution by adding 60 grams of sodium
hydroxide pellets (NaOH) very slowly with stirring to 600 mL of water. CAUTION:
Use Pyrex glassware as this reaction generates a large amount of heat. Stir
constantly while slowly adding the sodium hydroxide solution to the copper
sulfate solution.

In the presence of certain proteins, Biuret solution will turn a pink to
purple or violet color.

If the food contains only a small amount of fat, It may not be detected in
the brown paper test. if no fat has been detected, you may allow the students to
investigate further by dissolving a small amount of the food in a few mL of
nibbing alcohol. Allow the food to dissolve for about 5 minutes. Then pour the
solution onto a piece of brown paper and allow to dry. Then check for a
translucent spot on the brown paper.

Brown paper bags work well for this test if you avoid using the parts of the
bag with printing on it

The light source works well as a heat source to dry the papers. Place a
few inches from the paper after the food has been rubbed very hard into the

paper.
Here are some suggested test foods:

oatmeal apple
banana cooked egg white
spaghetti noodles crackers

potato cheese

80
Appendix C
Laboratory 1

FOOD TESTS

1mm: Scientists have ways of telling whether or not carbohydrates ,
fats or proteins are part of different kinds of food. They use special chemicals
that turn color when carbohydrates, fats or proteins make up a certain food. You
will do the same tests that scientists use to find out what kinds of substances are
apartofthefoodsyou eat

You will perform four different tests on several different foods. Two of
these tests are for carbohydrates (one for sugar, and another for starch), one Is
for fats, and one is for proteins.

For all of these tests, we will start with four very simple foods, and then
use a few more foods that you can bring from home. This will allow you to test
some of your favorite foods.

gum: Can we determine, in the laboratory, that the food we eat contains
carbohydrates, including sugars and starches, fats, or proteins?

Mandala: goggles
5 test tubes
test tube rack
a marking pen
Iodine solution
Benedict’s solution
biuret solution
2'x2'piecesofbrown paperbag
stirring rod
light source

W: 1. Using the pen, mark each of the test tubes 1-5. Then mark a line
approximately 2 cm from the bottom on each of these.
2. Fill the test tubes to the line with the following substances:
TT #1 water (control)
11’ #2 cornstarch solution (starch)
“IT #3 glucose solution (sugar)
TT# 4 gelatin solution (protein)
TI? 5 cooking oil (fat)
3. Create a data table for recording your observations.

SIABQHJESI

4. To test starch add a few drops of the Iodine solution to each of
the five test tubes. Observe and record the color of each food after the iodine
has been added.

81

(Iodine turns to a blue-black color in the presence of starch.)

5. Keep test tube #1 as a control. Use it to compare colors to see if
a reaction occurred in your foods from home.

6. Clean TT #2-5. Repeat the iodine test on the new foods. You
should use foods that are mostly white. Record the results in your data table.
Wash the test
tubes thoroughly.

W
7. To test for sugar, set up the experiment like you did for the

iodine solution. Number the test tubes 1-5. Make two lines, one 2 cm from the
bottom on each and another 4 cm from the bottom.

8. Add the substances in order from the starch test.

9. Add enough Benedict’s solution to each of the test tubes to fill
them to the second line.

10. Place The tubes in boiling water and boil for 3-5 minutes or
until you see a distinct color change. Compare the color to that of the control.

11. Add your observations to your data table.

12. Now perform the Benedict’s solution test with the foods from

home.

EBQIEIILIESI

13. To test for protein, use biuret solution. Set up the experiment
as you did before.

14. Add about 5-10 drops of biuret solution to the test tubes.
15. Check for color changes as compared to the control. NOTE: it
would be helpful if you use a white piece of paper for a background when
comparing the colors of the foods to the color of the control.
16. Record your data in the the table.
17. Test foods from home for protein.
EAISJISI
18. To test for fats, obtain five small pieces of brown paper bag.
Label each piece of paper with the name of the food substances tested:
#1: water (control)
#2: corn starch solution
#3: glucose solution
#4: gelatin solution
#5: cooking oil
19. Use a stirring rod or eye dropper to transfer a few drops of
each test solution to the appropriate piece of brown paper.
20. Allow the test spots on each sheet of brown paper to dry.
21. Compare the papers with the control. NOTE: The property of
light passing through the paper is called translucence. Note whether light
passes through the paper.
22. Record your observations in your table.
23. Test foods from home for the presence of fats.

82

W3 Data table.

W: Answers to the following questions should be included in the
conclusion.

Did your data support your hypothesis? Why or why not?

The first test tube, which contained water, was used as a control. How did
the
color change when the iodine, the Benedict's and the biuret solutions were
added.

Which test substance turned the Iodine color from yellow to blue-black?

Based on your observations, which component of food is the Iodine test
used to detect?

In test #2 the water was used as a control. What color was it after adding
the Benedict’s solution?

Which test substances changed the color of the Benedict’s?

Based on these observations, what component of food does the
Benedict's test for?

What happened to the water in test #3 when the biuret solution was
added?

Which test substances changed the color of the biuret solution?

Based on these observations what component of food does the biuret
solution test for?

Based on your observations of the way the four test substances and the
control reacted with the paper,thch of the four components of food can you
detect with this test?

Onthe baslsofthetestsyou have performed in thisandthe lastthree
activities,
which foods brought from home, that you tested, could be a good source of
starch? sugar? protein? fat?

Which of the foods from home contained more than one component?

Did any of your foods from home contain all four components?

Based on the evidence you acquired, what foods would you eat for the
energy your body needs? Please explain you answer.

Adopted from 'Food, Energy, and Growfl'l', New Directions Teaching Materials,
Michigan Department of Education, August, 1992.

83
APPENDIX C
Laboratory 3

THE SEPARATION OF PLANT PIGKENT DY PAPER
CHROMATOGRAPHY

W: Chromatography, a technique developed sometime immediately
following World War ii, is used to separate organic compounds from mixtures on
the basis of their solubility in one or more solvents passed through a solid
medium. The compounds that are most soluble in the solvent travel the fastest
along the medium, and those that are least soluble travel the slowest

Paper chromatography starts with making a stain of the mixture to be
analyzed on a piece of absorbent (chromatographic) filter paper. The stain is
placed near the bottom edge of the paper and allowed to dry. Once dry, the
edge of the paper with the stain is lowered into a solvent in a closed container
(if the container is not air tight the solvent will evaporate affecting the outcome.
The solvent climbs up through the paper by capillary action. It quickly reaches
the stain and passes it .

As a result, the molecules adhere weakly to the paper or dissolve easily.
Those molecules are quickly carried away in the advancing solvent ‘front'.
Other molecules stick more tightly to the paper, or are less soluble in the
solvent, or are large and heavy. Those are carried away at slower rates. This
causes the molecules to finally separate into bands in order of those speeds.
This series of separate, colored bands on a piece of the absorbent filter paper is
known as a chromatogram. in this activity you will use paper chromatography to
separate pigments within different types of vegetables.

mm: Can more than one colored pigment be found in vegetables?

m: 95% ethanol or acetone

3 large test tubes

test tube rack

toothpicks

parafilm
chromatography paper
spinach leaves

carrots

beets

Mn: 1) Cut chromatography paper in long, thin strips in order to slide
them into the test tubes (3 strips). NOTE: The paper should suspend without
touching the sides or the bottom of the test tube.

2) Place a toothpick into one end of each of the three paper strips
so that they can be suspended into the three large test tubes. (See Diagram)

84

3) Cut up the vegetables into tiny pieces.

4) Blend each vegetable separately with 5-10 mL of 95% ethanol
or acetone in the mortar and pestle.

5) Filter the mixture through 3 layers of cheesecloth or through a
double strainer.

6) Place a thick line of the filtrate approximately 2 cm from the
bottom on the filter paper (end opposite the toothpick), using another toothpick.
Go over and over the line many times Ietfing the extract dry between each
application.

7) While the extract is drying, pour some solvent into the test tubes.
Add enough so that the end of the paper strip, when placed in the tube will be
submerged.

NOTE: Be sure the extract line is not submerged.

8)Suspend the paper in the test tubes and allow about 112 cm to
touch the solvent.

9) Immediately cover each test tube with the parafilm. NOTE: This
allows the environment inside the test tubes to become saturated with the
solvent.

10) Do not disturb the test tubes for 10-15 minutes, or until the
solvent has risen to a point at the top of the paper strip.

11)Remove the paper strips and allow them to air dry.

12) Record your observations in a data table.

annotations: Data Table

W: Answer the following questions in a paragraph:
Did your data support your hypothesis? Why or why not?

What color pigments are found in spinach, carrots, beets?

If chlorophyll is green, how do you explain the presence of other
pigments?

What pigment is the most soluble? Which is the least soluble?

If only one pigment color can be seen on your chromatogram.
what might this suggest?

Going further: When the chromatography is complete, take the distance (from
the stating point) moved by a particular substance and divide it by the distance
(from the starting point) moved by the solvent. That ratio is referred to as the Rf
(rate of flow) value of that substance under certain conditions of temperature
and solvent composition. The Rt value of a compound can be used to help
identify it

distance traveled by compound

Rf a
distance traveled by solvent

Adopted from NSC 852 Units, Michigan State University, Summer, 1992.

85
APPENDIX C
Laboratory 4

LIGHT AND CHLOROPHYLL LABORATORY

W: The major light-absorbing pigment in plants is chlorophyll. In
green plants, chloropth is found in chloroplasts within plant cells.

When atoms in a pigment absorb light, electrons are boosted to higher
energy levels. The energy in the photons is transferred to the electrons, causing
the move. Boosting an electron requires an exact amount of energy, just as
when climbing a ladder you must raise your foot just so far to climb to the next
rung. A particular kind of pigment can absorb only photons with the appropriate
amount of energy.

in the second stage of photosynthesis, light energy Is converted into
chemical energy by a series of reactions that is initiated when light is absorbed
by the photosystems.

gum How does the color of light affect the development of chlorophyll in
seedfings?

111221119311:

Willi paper towels
bean seeds
5 small glass jars with lids (baby food jars work well)
cellophane, red, blue, green, yellow, and clear (colored plastic
wrap works well)
masking tape
felt-tip pen

m: 1) Cover the bottom of each jar with a damp paper towel. Place
two-three bean seeds on the towel in each jar. Tightly corner the jars with their
lids.

2) Completely wrap each jar with one of the pieces of colored
cellophane. Use the masking tape to make a label for the lid of each jar.

3) Place the jars in a well-lighted area where they will not be
disturbed.
DA YS 2-8..

4) Check the seeds daily. After seven days, remove the
cellophane from
the jars and observe the color of the seedlings. Do not open the jars.

5) Record your observations.

6) After 24 hours, observe the color of the seedlings.

86

: Record your observations in a data table and
answer the following question:
What color were the seedlings in the jar wrapped in clear cellophane?
What color were the seedlings in the jars wrapped in colored
cellophane?
What color of light was reflected from each jar wrapped in cellophane?
What colors of light passed through to the seedlings?

Wm: Answer the following questions in a paragraph:
Was your hypothesis correct? What were the white seedlings missing?
Why were they missing It?
What color of light is required for photosynthesis to occur?

References: Marson, Ron, Light: Tops Leamlng Systems, #17, 1991.

   

87
APPENDIX C
Laboratory 5

RESPIRATION INVESTIGATION

: All aerobic organisms take in oxygen and give off carbon dioxide
as long as they are alive. This is true for plants as well as animals.
some organisms have elaborate structures such as lungs or tracheal tubes for
exchanging respiratory gases; others merely use moist membranes if you place
a living organism in a closed system, it is possible to measure its consumption
of oxygen. Respiration will be measured in

mL OglminJg of organisms
m: Can the respiration rate of germinating seeds be measured? _

mu: Respirometer
large test tube
2-hole rubber stopper to fit test tube
4-glass tubes to fit snugly into holes of stopper (5-10 cm long)
syringe, without needle
latex tubing (45 cm, and 3 cm lengths)
1 or 2 mL pipette
Colored liquid detergent (Add red food coloring to liquid
detergent)
NaOH or KOH pellets (2-5 grams) NOTE: Limewater may also be

" "‘3‘ Cotton balls
Tablas Cork grease or Vaseline

I 5&3. Pea or corn seeds ( 45 pea seeds or 40 com seeds which are
, ' germinating)
Test tube rack
New Balance
0““ Eyedropper

s
m: I) Set up the respirometer as shown in the diagram.

2) Put about 3 cm 002 absorbent (either KOH or NaOH) in the
[bottom of the test tube. NOTE: The KOH of NaOH will absorb the carbon
dioxide that the organisms are giving off. which might interfere with your
measurement of oxygen uptake. DO NOT TOUCH THE ABSORBENT.

3) Find the mass of the germinating seeds by placing them on the
balance. Record the mass in a data table.

4) Place the germinating seeds on top of moist cotton in the
respirometer. (See diagram)

5) Seal the respirometer joints with a small amount of Vaseline.

NOTE: Make sure the rubber stapper is seated securely in the test tube. DO
NOT PUT TOO MUCH GREASE ON THE JOINTS.

6) Place a drop of colored liquid detergent into the tip of the
pipette with the eyedropper. The drop should be 3-4 mm long. NOTE: Let the
respirometer stabilize for 5 minutes.

7) After 5 minutes, adjust the marker drop to the end of the
pipette with the syringe. NOTE: Pulling quickly on the syringe will break the
bubble of dye. Twist or turn the syringe rather that pulling on It.

8) Check the time and record the initial volume in the data table.
Every 3 minutes, record the change in volume. Take 10 readings and then
disassemble your respirometer.

WWW: Data Table Number 1

Calculations: Calculate the average amount of oxygen your specimens
used every 3 minutes.

Calculate the average amount of oxygen your germinating
seeds used every minute.

Using the above answer, calculate the average respiratory
rate of your organisms per gram of organisms. (mL OzlminJg specimens)

W Answer the following questions in a paragraph:
Was your hypothesis correct?

How do you think the respiration rate of insects would compare to the
respiration of germinating seeds?

Explain your answer thoroughly.

What were some problems you encountered in this lab?

it is important during this lab to keep the temperature of the environment
constant. This experiment was run at room temperature. Do you think that the
temperature remained constant?

How might you design this experiment so that you could be sure it was
conducted at a constant temperature?

What other experiments could you conduct using your respirometer?

Adopted from NSC 852 Units, Michigan State University, Summer, 1992.

89

DATA TABLE 1

Name of organisms tested:

Mass of organisms
Number of organisms tested

Time Initial Volume FInal Vobme A Volume

 

O

 

3

 

 

 

12

 

15

 

Is

 

21

 

24

 

27

 

3O

 

 

 

 

 

 

90
APPENDIX C

Laboratory 6

VARIATIONS IN CARBON DIOXIDE PRODUCTION
Using Instant Ilene! Dry Yeast

Introduction: This experiment illustrates some interesting results when using
like amounts of yeast and water with varying amounts of sugar. The production
of carbon dioxide begins when the yeast comes in contact with moisture and
sugar. The amount of sugar In proportion to yeast is one of the important
aspects of carbon dioxide production.

Yeast cells digest food; their favorite foods are sugars. The end products
of this fermentation are carbon dioxide and ethyl alcohol. In bread making, the
yeast digests the sugars available from flour and added sugars.

After most yeast recipes are mixed and kneaded, the dough is covered
and allowed to “proof” of rise to double its size before baking. During the first 10
minutes of baking, another rapid expansion (oven-spring) occurs. The rising in
each case is caused by the accumulation or trapping of carbon dioxide gas as
bubbles in the soft dough.

Purpose: Will the amount of sugar affect the yeast fermentation?
Hypothesis:

Materials: 4 test tubes
timer or second hand on watch or clock
2 packages Instant Blend Dry Yeast
3 colored pencils
4 100 ml beakers
warm water
lherrnometer
sugar
felt pen or china marker

Procedure: 1) Label the beakers A,B,C, and D.
2) Into each cup measure 1 teaspoon Instant Blend Dry Yeast.
Measure 1 teaspoon sugar into cup A; 2 teaspoons sugar into cup
8; 4 teaspoon sugar into cup C and 6 teaspoons sugar into cup D.
Stir each to combine.
3) Add 1/2 cup 110 F (43 C) water to each cup. Stir each to
dissolve and combine ingredients.
4) Add the ingredients to the test nibes.
5) Set timer and observe changes every five minutes for fifteen
minutes.
Record results of observations on Data Sheet

91

Observations: See attached data sheet.

Conclusions: Did the increased sugar produce the results you expected?
What appears to be different in the results of Cups C and D from

Cups A and B? Can you explain what happened in terms of the
microorganisms?

92

DATA SHEET YEAST EXPERIMENT
Variations in Carbon Dioxide (C02) Production Using instant Blend Dry Yeast
Yeast and water with varying amounts of sugar

Record on the graph below, the inches of carbon dioxide (C02) in each test tube
at 5 minute intervals by coloring the height with one colored pencil. Use a sec
ond color for the next 5 minute measurement, etc.

COLOR KEY: 1st 5 minutes 2nd 5 minutes

 

 

 

3rd 5 minutes __

 

 

 

 

5 inches

 

4% inches

 

4 inches

 

3‘23 inches

 

3 inches

 

2% inches

 

2 inches

 

1% inches

 

1 inch

 

‘15 inch

 

 

 

 

 

 

 

 

 

CUP A CUP 8 CUP C CUP D
1 teaspoon 2 teaspoons 4 teaspoons 6 teaspoons
sugar sugar sugar sugar

 

CONCLUSIONS:

 

93
APPENDIX C
Laboratory 7

YEAST PERMENTATION

W: Yeasts are microorganisms, single-celled fungi, noted
particularly for their ability to ferment carbohydrates. The yeast is the oldest
domesticated life form on Earth. There are more than 600 species of yeasts. The
ability of yeast such as Saccharomyces cerevisiae to ferment carbohydrates by
breaking down glucose to produce ethanol and carbon dioxide is fundamental
to the production of breads and other baked goods, as well as beer, wine, and
liquor. Yeast cells use sugars naturally as their energy source. In digesting
these sugars, yeast cells produce 002 and ethyl alcohol. The rising of bread is
caused by the accumulation or trapping of carbon dioxide gas as bubbles in the
soft dough. The carbon dioxide is trapped because the dough is elastic and
stretchable. it is not possible for the gas to rise up through the dough and
escape. The alcohol dissolves in the water and evaporates. In this lab you will
use yeasts to make root beer.

gum: Does yeast fermentation produce root beer?
Hypothesis:

mm: Fresh yeast, Champagne yeast If available
Measuring spoons and cups
Small cups to hold water
Gallon Jugs to mix ingredients
Sugar (5 pounds)
Mixing stirrers
Root beer extract
Funnel
Masking tape and marking pencils
Note to teacher: You can purchase the Champagne yeast and root beer
extract at a beer/wine-making supply store.

m: 1) Dissolve 1 teaspoon of sugar in 1/2 cup of warm water.

2) Dissolve 1/4 teaspoon Champagne yeast in sugar and water
mixture. NOTE: If the water is too hot, it will kill the yeasts.

3) Allow the mixture to set for a few minutes.

4) Add 2 cups of sugar to the clean gallon jug.

5) Add 1 Tablespoon of root beer extract to the sugar in the jug.

6) Now add the incredible yeast mixture to the gallon jug.

7) Add enough warm water to make a gallon.

8) Put the top on the gallon jug and shake It gently to mix all the

ingredients.

94

9) FIII the sterilized plastic pop bottles with the mixture. NOTE: To
sterilize the plastic pop bottles fill the bottles with boiling
water. Let stand for 3 minutes and repeat two more times.
Boil the bottle caps and reseai immediately after the last hot
water sterilization.

10) Make sure to seal the bottles properly or the mixture becomes
flat and sour.

11) Lay the bottles on their sides to check for leaks.

12) Age for two to four days.

13) After that time, store in a cool dark place, aging for at least one
week, two weeks improves the flavor. NOTE: A slight yeast deposit will form on
the bottom of the bottle. When serving, pour carefully so as to leave this deposit
in the bottle. It is not harrnfull

WW1: Did you note any visual changes In the

mixture?
What did the mixture taste like?

W: What gave the mixture its flavor?
Was the mixture fizzy? If it was, how can you explain this?
What other food products do we have as a result of microbe
fermentations?

 
 

Adoptedfrom, II: ll 0." III. II II -
Space, Kendall/Hunt, Boston University, 1992.

95
APPENDIX C
Laboratory 8

RACTERIOLOGY OP YOGURT

W Yogurt fermentation is brought about by inoculation of boiled
milk with two lactic acid bacteria, Lactobacillus bulgaricus (adds flavor and
aroma) and Streptococcus therrnophilus (produces acid). The aroma and flavor
of yogurt are due primarily to the lactic acid produced by these bacteria.
Chemical metabolism of the fermenting bacteria includes changing lactose
(milk sugar) into lactic acid. Lactose is the carbohydrate which supports
microbial growth and lactic acid is the resultant waste product. Yogurt has a
custard-like appearance due to coagulation of milk protein by the lactic acid. in
this experiment you will make yogurt. A portion of this product will then be
plated to show the two types of bacteria. A gram stain of each organism will also
be done to confirm the presence of the two above mentioned bacteria.

gum: Can microorganisms change milk into yogurt?

mm: To make yogurt:
1 quart skim (nonfat) milk

1 Tablespoon plain yogurt with active yogurt cultures (i.e., Dannon
or Yoplait)

4 Tablespoons nonfat dry milk (Increases the solids so that the
final product will be thicker, more like commercial yogurt) NOTE: Make sure the
dry milk dissolves.

Non-mercury thermometer (A candy thennometer works well)
1 quart thermos

Mixing spoon

Pan and hot plate or hot pot or yogurt makers

For staining:

Plate Count Agar (For cultivating bacteria)

Microscope slide (For gram stain)

Microscope

Inoculating loop

Methylene blue stain (Gram staining is another option)
Test tube holder (To hold slide)

Bunsen burner or alcohol burner

m: 1) Pour the milk into a clean pot of hot pot

2) Stir in the 4 Tablespoons of nonfat dry milk

3) Heat the milk on the hot plate or in the hot pot to 82 C. Maintain
this temperature for 15-20 minutes. NOTE: stir continuously so mat milk does
not burn. Heating the milk to just below the boiling point is done to kill any bad

96

bacteria or microorganisms that might be present.

4) Cool the milk to 43 C. NOTE: You can speed this cooling if you
place the pan in ice water. and stir.

5) Stir in 1 Tablespoon of yogurt culture. Mix with a genfie stirring
motion. NOTE: You want to minimize the addition of air to the yogurt.

6) immediately pour the yogurt into clean containers (50 mL
beakers work well) Cover the containers and incubate (45 C) undisturbed until
the product gels or coagulates. NOTE: Temperature should not exceed 46 C
because temperatures above this will kill the culture. The bacteria will also grow
at room temperatures, but at a slower rate. If you decide to make the yogurt at
room temperature it will take longer. If you do not have a thermos, you can use
warm water in a pan placed near a heat source. An Incubator will work or an
actual yogurt maker will do a nice job as well.

7) Refrigerate the containers. Eat when desired!

Staining:
8) Place a small amount of yogurt onto a clean slide with an

inoculating loop or toothpick. Spread the culture around in a circle to form a thin
film. NOTE: Do not prepare too heavy of a smear.

9) Allow the slide to air dry, then ‘fix' the culture by passing it, flim
side up, quickly three times through a Bunsen flame. NOTE: Too much heat will
distort the normal shape and structure of the microorganisms to be stained.

10) After preparing a smear, place the slide on a staining bar over
one of the lab sinks.

11) Flood the slide with methylene blue. Rinse the slide gently
with water.

12) Blot dry very gently (Do not rub the culture off) and examine
under low power, than high power. if time permits also vies under all immersion.

13) Make drawings of the various bacterial cultures.

W: Drawings of the bacterial cultures on low and high power.

Wm: Answer the following questions in a paragraph:

Was your hypothesis correct?

What were the shape and structure of the bacteria you saw?

Were they cocci or bacilli?

Were the bacteria in chains or clusters?

What does “active” cultures mean?

Why must yogurt be kept in a warm place?

What is the effect of refrigeration on the action of the bacteria?

What do the bacteria use as their source of energy?

How did that energy get in the yogurt?
Include a diagram showing where the energy transformations
occuned so that yogurt could provide energy for the bacteria.

References: ' . '
National FFA foundation, Madison, WI, The National Council for Agricultural
Education, 1993.

 

EundamemaimnamLQhamrsmr. Wong. N.P.. Jennecs. 8..
Keeney, M. Marth, E.H., VanNostrand Reinhold Co. NY. 1988.

APPENDIX D

APPENDIX D

PICTURES FOR CONCEPT MAPPING

O

CO, Oxygen

Carbon Dioxide

CSHI2OI

H20
Glucose

Water

-------A-------

.

Respiration Photosynthesis

.. '.' Energy Captured

—>

@ Mitochondria

J

 

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Chlorophyll

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99
APPENDIX D

Chlorophyll Sugar

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APPENDIX E

APPENDIX E

THE ROLE OF MICROORGANISMS AND FERMENTATION IN
FOOD PRODUCTION

Numerous food products owe their production and characteristics to the
activities of microorganisms. Foods such as ripened cheeses, pickles,
sauerkraut, and lamented sausages and salami have an extended shelf life
over their base raw products. Fermented foods also have aroma and flavor
characteristics that result directly or indirectly from the fermenting organisms.
Yeasts, bacteria, molds, or combinations of these organisms are responsible for
fermentation. Bread, beer, wine and distilled liquors are generally fermented by
yeasts. Yeasts and bacteria are involved in the manufacture of vinegar from
sugar-bearing materials. Bacteria are responsible primarily in the production of
fermented milks and milk products. Molds are important In the preparation of
some cheeses and Oriental foods.

Throughout and during the development of human kind, individuals have
Ieamed how to utilize and manipulate the growth of microorganisms for food
preparation, development and preservation. The bacterial microorganisms and
their perspective by-products utilized most by individuals are those that produce
lactic acid.

Lactic acid fermentation of foods such as vegetables (cucumbers,
cabbage, olives) and dairy products (some cheeses, buttermilk, yogurt) not only
helps preserve foods but gives “lamented” foods a distinctive flavor, texture,
and aroma. Lactic acid is produced by lactic acid bacteria.

Yeasts are noted for their ability to ferment carbohydrates. “Favorite
foods” of yeasts are sugars (sucrose, glucose, fructose, etc.). The results of this
fermentation are carbon dioxide and ethyl alcohol . In 1859, Pasteur proved that
the result of live activity by tiny yeasts was fermentation. Pasteur’s discoveries
prompted a new area of research which has since produced volumes of
information for medicine, public health, and industry.

Fermentation occurs under anaerobic conditions differently in eukaryotes
than in prokaryotes. There are two different products of fermentation among
eukaryotes. in the human animal, lactic acid is produced. If you lift a heavy
weight up and down rapidly 100 times, for example, your muscle cells get only
two molecules of ATP from glycoiysis. This situation immediately produces a
tired feeling in your muscles. Later, lactic acid in your muscle cells causes your
muscles to feel sore. Fungi and plants have a different pathway for fermentation.
Ethyl alcohol Is produced as a result of these fermentations.

100

APPENDIX F

APPENDIX F

PHOTOSYSTEM CAPTURING ENERGY

pyright ISDO
yedlcete
eprteted with pet-leelee

Calvin and Iebbee Ce
All rights reserved

Delvereel frees I

 

 

   

101

102

APPENDIX E

ENERGY FLOWS ONE WAY

CO:
Water
LIGHT ENERGY Energy for lie
activities '
02 ATP
“W I
(foods) .
WWW“ W
Photosynthesis Respiration
Energy “fixers' Energy “releasers'
' muscle contractions
electrical potentials
acdve transport
synuletic activldes

APPENDIX G

APPENDIX G

JOURNAL ENTRIES

DAY 1
Write the word energy in ten sentences.

DAY 2
Write your definition of energy in your joumais.
Write this scientific definition of energy and compare it to your definition.
Energy is the ability to do work.
Write the definition for kinetic and potential energy:
Kinetic energy is energy due to an object's motion.
Potential energy is energy an object has do to its position or the
arrangement of it’s parts
Write down these examples:
Kinetic energy-thermal, light, sound, electricity
Potential energy-gravitational , elastic, chemical
If you think of anymore examples tonight write them in your joumals for
tomorrow.

DAY 3
First Law Of Thermodynamics
Energy cannot be created or destroyed.
Energy can be changed from one form to another, but the total amount of
energy never changes.
Second Law of Thermodynamics
Energy does run down in its ability to do work as It is passed from one
system to another on its way towards being heat.
Give an example of a system showing the Second Law.

DAY 5
In your joumais, draw a diagram or write a story, which represents the Laws of
Thermodynamics.

DAY e
Look at your energy sentences and tell whether or not energy and matter are
related.
Notes on Energy and Matter

-Piant and animal life on earth is an ordered collection of molecules
joined by bonds made of captured energy.

-Bonds are reservoirs of energy , like fuel, that can be put to work in cells

1 03

104

to accomplish life’s feats of moving, growing, and reproducing.
~Atoms contain kinetic energy as they careen through space. if the kinetic
energy of two atoms is great enough, two atoms stick together (chemical
reaction) and a molecule is formed.

-The atoms in a molecule can share some electrons. This is called a
covalent bond which is difficult to break. Covalent bonds hold life’s key atoms-
carbon, hydrogen, oxygen, nitrogen, phosphorus, etc., together in simple
molecules and they join those simple molecules together in chains.

-Cells need to be able to break bonds to rearrange molecules no longer
needed. When a bond breaks, the shared electrons fall back into the original
orbits around the separated atoms, releasing the energy as heat. (At this tlrne
demonstrate with a rubber band how when the band is stretched out,
representing the electrons further from the nucleus with greater potential
energy. it can cause more damage than when it is not stretched out,
representing electrons closer to the nucleus with less potential energy.)

-Cells need to be able to break bonds to rearrange molecules in all sorts
of ways and to dispose of molecules no longer needed. When a bond breaks,
the shared electrons fall back into the original orbits around the separated
atoms, releasing the energy as heat

-When high energy bonds are broken, the energy is sometimes
transferred to other molecules.

Everything that happens in living cells is the result of various
combinations of bond-breaking, bond-making, and bond transfer.

DAY 9

WW
ATP-the “energy currency' of the cell
TEACHER NOTE:

(20 trillion cells in human body use 1 billion ATP molecules per minute. You
recycle 2-3 pounds of ATP everyday. To make that much ATP you must
consume 3000 cal/day. The energy consumed by one person each day is equal
to energy found in 2.7 kg of dynamite)

Energy is contained in the phosphate bonds. A——-P P P

When life needs energy, it breaks off one of ATP’s phosphates which frees the
energy from the bond.

Enzymes are catalysts which work with ATP. They trigger and control particular
chemical reactions. (Without enzymes, chemical reactions necessary for life
would not occur at a rate sufficient for sustaining life)

Cells use energy to do those things that require work. i.e., movement, changing
shape, white blood cell engulfing a bacterium, building new molecules.

105

DAY 10
FOOD NUTRIENTS

Almost all chemical compounds In living things are made up of combinations of
carbon, hydrogen, oxygen, and nitrogen.

These compounds are divided Into two groups:
Inorganic-mom hat do not contain carbon (exception is 00 and 002)

manic-those that do contain carbon

Carbon is unique because of its ability to form strong and stable covalent
bands. It can form chains of almost unlimited length.

Organic compounds

1. Carbohydrates=sugars, containing Carbon , Hydrogen, and Oxygen
Used to provide energy

Monosaccharides-simplest sugars
glucose, fructose

Disaccharides-double sugars
sucrose, lactose

Poiysaccharides-groups of monosaccharldes
starch, glycogen, cellulose

2. Lipids-waxy or oily compounds
Used to store energy
fatty acids. glycerol, sterols, phospholipids
Lipids can be saturated or unsaturated.

Polyunsaturated fats tend to prevent heart disease.

3. Proteins-polymers of amino acids which contain Nitrogen as well as Carbon
Hydrogen, Oxygen
Used to carry out chemical reactions, pump molecules in and out of cells,
and
responsible for cell’s ability to move
Enzymes are proteins.

4. Nucleic Acids-contain Carbon, Oxygen, Nitrogen and Phosphorus
Used to store and transmit genetic information
RNA and DNA

106

DAY 13
BIG IDEAS

W the process by which green plants take energy form
sunlight to transform 002 and H20 (along with a few trace elements) through
particular chemical reactions into food for the plant along with oxygen gas as a
by-product, which is released into the atmosphere.

REM-Cells combine complex molecules (made by plants or by
other animals which have eaten plants) with oxygen in a chemical reaction
which produces 002, water and energy, along with other by-products. This
energy is used by the organism for Its life functions.

In photosynthesis, 002, H20, and energy form sunlight = the plant stuff and 02.
and the plant stuff (food) combine to make H20, 002, and energy.

Plant and animal like form a kind of cycle each supporting and depending on
the other. Energy to make the whole thing work comes from the sun, with plants
receiving energy from sunlight and converting it into a form usable by
themselves and animals.

 

Wag
ENERGY + CARBON DIOXIDE 4» WATER ‘. A» GLUCOSE -I- OXYGEN
reapirwon

 

W
ENERGY -I- C02 + H20 ‘ CaH1203 + 02
respiration

 

enzyrnee
GLUCOSE + OXYGEN \ A CARBON DIOXIDE -I- WATER + ATP

enzymes X
05H1203 -I- 602 6002 + 6H2O + 36ATP

‘—

 

DAY 12
See typed notes In Appendix E.

DAY 25
In your journals write a story about your life as a photon of light and your
travels through an ecosystem as energy that changes form.

107

DAY 26

You will need to discuss the habitats you have chosen for your
Ecocolumns. include naming the organisms that you have used in your column
and how the organisms interact. Where do the living creatures get their energy?
What do the organisms need to remain alive? Explain any other interesting
ideas you have included in the creating and constructing of your Ecocolumn.

APPENDIX H

APPENDIX H

DEMONSTRATING ENERGY TRANSFORMATIONS

Answer in complete sentences. Explain all of your answers.

PART I KINETIC ENERGY

1. An object contains energy if it has the ability to do work. What does the
moving bail do that convinces you it has energy?

2. The energy of moving objects is called kinetic energy. Two factors determine
the amount of kinetic energy an object possesses: how fast it is moving (Its
velocity), and the mass of the object. if a bowling ball and a basketball are
moving at the same speed, the more massive bowling ball will have more
kinetic energy. When the moving ball hits the stationary ball at the bottom of the
tube, there is a transfer of energy. The moving ball has what kind of energy?
The stationary ball acquires what form of energy?

3. What energy transformation is taking place in this demonstration?

PART II WORK AND HEAT ENERGY

4. When objects are bent or stretched or rubbed, work is usually being done on
them, and they acquire energy. Some of that energy Is in what form?

5. When a driver applies the brakes to stop a moving automobile, the brake pad
rubs against a metal plate. Would you expect the brake pads to become hotter,
colder, or stay the same temperature while the car is slowing down?

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109
APPENDIX H

PART III GRAVITATIONAL POTENTIAL ENERGY

6. Non-moving objects can have the ability to do work: They can have potential
energy. Potential energy that is due to an object’s position in a gravity field
(such as the Earth’s) Is called gravitational energy. The grapefruit and the brick,
when held stationary over the head, have gravitational potential energy. That
potential energy is transformed into what form of energy as the object 8 fall?

7. Catching a grapefruit that falls 1 meter is easy, but your hand would be
injured if you dropped a brick on it from a height of 1 meter. (Do not try this!)
Which object, the grapefruit or the brick, would transfer more energy to your
hand? Which object, therefore, has more potential energy when held 1 meter
above your hand?

PART IV ELASTIC POTENTIAL ENERGY

8. Another type of stored energy in non-moving objects is elastic potential
energy. This energy is stored in the molecules of objects that are stretched or
compressed. The compressed spring of the toy has elastic potential energy.
This potential energy is transformed into what form of energy the instant the toy
takes off? When the toy stops what form of energy does it have in the spring?

PART V omen. POTENTIAL ENERGY

9. Work was done on the balloon to stretch It out. Therefore, the balloon
required elastic potential energy. That energy must have come from the
chemicals that reacted. The energy stored in the chemicals is called chemical
potential energy. Some of the chemical potential energy was transformed into
what form of energy in the stretched balloon?

10. If you stick a pin into the inflated balloon, the elastic potential energy is
transfonned Into what fonn(s) of energy?

Reference:

‘ ; . ' ,Gartrell,JackE.,
Jr., Schafer, Lany E., NSTA, 1990.

 

APPENDIX I

APPENDIX I

 

 

BIOLOGY NAME
ENERGY OUIZ HOUR
1. Define energy.

2. Compare kinetic energy and potential energy.

3. List and describe 3 kinds of potential energy.

4. State the First and Second Laws of Thermodynamics and explain what they
mean. Use explanations in your explanations.

5. Explain how an automobile and the human body are similar and how they
are different. In your explanation, include a comparison of the fuel needed, the
transferences of energy involved, and the physical or biological make-up of
both.

6. Where is the energy stored in and atom? In a molecule?

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111

7. ATP is called the “energy currency” of the cell. What does this mean?

8. What jobs does ATP have?

9. Potential energy is stored in food. Where is this energy found in food?

10. What is the relationship between enzymes and ATP?

BONUS QUESTIONS
11. What is food for plants?

12. Where do plants get their energy to grow, reproduce, etc?

APPENDIX J

APPENDIX J

MODELS OF THE PROCESSES OF PHOTOSYNTHESIS AND
RESPIRATION

15m

pink or orange marshmallow=Hydrogen atom
green marshmallow=0arbon atom
yellow marshmallow=0xygen
toothpick=bond between the atoms

W

First, build 6 models of 002 and H20 using the marshmallows and toothpicks.
From these molecules, build or produce the products, 02 and 05H1203

Question: What are the possible origins of the oxygen atoms in the
carbohydrate product of photosynthesis?

W

First, build 1 model of 06H1203 and 6 molecules of 02 from the marshmallows
and toothpicks. From these, now produce as many H20 and 002 molecules as
you can.

Questions: What are the possible origins of the oxygen atoms in the respiration
product 002?

How many molecules of H20 and 002 did you end up producing?

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113

As a result of your model-building, you should be able to write the chemical
equations for both photosynthesis and respiration in the space below. If you
cannot, you may look up this information in your textbook or your notes
What relationship exists between photosynthesis and respiration?

APPENDIX K

APPENDIX K

“Boosting” Electrons Metaphor

There is an apartment house with several floors. Clumsy bowlers live
here and constantly move from one apartment into the next. The upper floor
apartments cost more than the lower levels. When residents get raises at their
jobs they move to higher floors. When they lose their jobs or get pay cuts, they
move down to a lower level. Each time they move they take their bowling balls.
Each clumsy bowler drops his/her bowling ball down the stairs when moving,
and the ball falls to the bottom of the complex. It the clumsy bowlers who live on
a higher level drop their balls, the balls cause a lot of damage because they
have a lot of energy. However, if the dwellers drop their balls from a lower level,
the balls do less damage because they have less energy.

Questions to consider:
1) Energy added to atoms makes electrons move to different levels in the atom.
How is this like the model?

2) Which has more energy an electron in a lower level or an electron in a higher
level?

114

APPENDIX L

APPENDIX L

STORY OF PHOTOSYNTHESIS

As light energy is absorbed by chlorophyll in the living cells of the leaf,
the orbiting particles of many atoms become “excited”. To understand how the
excited particles of chlorophyll do their work, Imagine that you go to the circus
and meet a team of acrobats. Among the members of the team is a fellow
whose name is Electron. As we get to know him better we notice that he has
almost peculiar behavior. When the lights go up in the tent and it’s time to do his
act, Electron gets very excited. His part of the act is very simple. He climbs
rapidly to the top of a series of green steps and jumps off, dropping to the end of
a springboard. He does the same thing over and over as long as the lights are
on.

Other interesting members of the group are Carbon Dioxide and the
manager of the group, who is called ATP. The manager always has a box of
candy bars handy when the act is about to start. His strong man Carbon Dioxide
needs the extra energy in the candy that ATP gives him or Carbon Dioxide
cannot complete his part of the act.

Strengthened with the energy from the candy bar, Carbon Dioxide takes
his place in the ring. Other members of the team, the Hydrogen twins and
Oxygen, climb on one end of the springboard. To keep from falling off the small
space, they all clutch hands tightly. Now that everyone is in place, Electron
climbs to the top of the steps and without hesitation drops to the opposite end of
the springboard. As Electron hits his end of the springboard, the Hydrogen
twins and Oxygen fly into the air. But something is wrong. Oxygen was the
clown and is no longer part of the performance. But what happened to the
Hydrogen twins? What an act. They have landed on the shoulders of Carbon
dioxide. The strength from ATP’s candy works wonders. He has the Hydrogen
twins grasped tightly by the ankles. They stand as one, united in the middle of
the ring. Amid thunderous applause, the lights go down and Electron goes to
sleep until the lights go up for the next performance.

115

1 16
APPENDIX L
EXPLANATION OF THE PHOTOSYNTHESIS STORY
1. “Electron” is just what his name implies.

2. Light going on in the tent is the light energy that excites the electrons of the
chlorophyll molecule. In the analogy the green steps and Electron represent the
chlorophyll molecule.

3. Light energy is provided to Electron at each step of the ladder. His potential
energy increases with each step he takes up the ladder.

4. The introduction of ATP and its energy-yielding characteristic will serve to
give the student some insight into the complexity of photosynthesis.

5. Electron’s potential energy becomes active energy as he drops and hits the
springboard. Most of the energy that Electron gained in his trip to the top of the
steps is converted to another kind of energy in the springboard.

6. Energy is transferred through the springboard to a water molecule, the
Hydrogen twins and Oxygen (H20).

7. The transferred energy is transformed into another kind of energy, breaking
the water molecule apart (H-O-H).

8.0xygen rolls out of the ring. This represents the release of atmospheric
oxygen. (Release of 02 from plants’ activities)

9. Carbon dioxide enters the picture.

10. Emphasize that light energy, by exciting Electron to go up steps, has
provided the energy to break the water molecule.

11. At the end of the story we left the Hydrogen twins on Carbon Dioxide’s
shoulders, locked together In one unit of 0, H, and 0. Here the student must be
made to realize that when atoms are combined into a molecule of glucose, the
molecule contains great amounts of stored energy that was transferred to it from
Electron and ATP.

WHO". Rinehart and Winston. Inc.
1966.

APPENDIX M

APPENDIX M

From Sugar-making To Sugar-burning

Energy flows into the biological world from the sun. Life exists on Earth
because photosynthesis makes it possible to capture some of the light energy
from the sun and transform it into the chemical energy of organic molecules.
These organic compounds compose what we call food.

Mum-capture the energy from the sun (i.e., plants, some bacteria and
algae)
Mailman-obtain energy by consuming other organisms

W-where an organism is placed dependent on its source of energy
Producers occupy the first trophic level

magma-organisms that consume plants occupy the second level
Wergansims that consume flesh andijm-organisms that
consume plants and flesh occupy the remaining levels.
film-organisms that obtain their energy from dead organisms and
organic wastes (i.e., fungus, some bacteria, vultures, and worms)

Momma-cause decay (i.e., bacteria and fungi)
Mtg-the path of energy flow in an ecosystem

Every transfer of energy within an ecosystem dissipates energy as heat.
Although heat can be harnessed to do work (as in a steam engine), it is
generally not a useful source of energy for biological systems. Thus, from a
biological point of view, the amount of useful energy available to do work
decreases as energy passes through an ecosystem. At each trophic level, the
energy stored by the organisms is about one-tenth of that stored by the
organisms in the level below.

Ecologists often portray the flow of energy through ecosystems by means
of a block diagram called a W. In this diagram, each trophic
level is represented by a block, and blocks are stacked atop one another, with
the lowest trophic level on the bottom. The width of each block is determined by
the amount of energy stored in me organisms at that trophic level. Because the
energy stored by the organisms at each trophic level is about one-tenth of that
stored by the organisms in the level below, the diagram is a pyramid.

117

APPENDIX N

APPENDIX N

PYRAMID OF ENERGY

Scientists estimate that only 10 percent of the energy present at each level of
the food chain is available to the next higher level. Scientists further estimate
that 1 percent of the energy from the sun that reaches photosynthetic organisms
is converted from light energy to chemical energy during photosynthesis. Based
on this lnfonnation, study the two energy pyramids and answer the questions
below.

 

 

1. Assume that 1 million kcal of energy from the sun Is available to the
producers In the food chains above. Determine the amount of energy that will
be available at every level of each food chain and fill In the blanks beside each
level.

2. What is the total amount of energy available to the human at the top of energy
pyramid A? Energy pyramid B?

3. Most terrestrial ecosystems consist of no more than three or four trophic
levels. Why do you think this is true?

4. What happens to the energy that does not advance from one level to the next
higher one?

5. Earth’s population Is expanding at a rate that may outpace our ability to
produce enough food. Why are some people promoting vegetarianism as an
answer to this dilemma?

118

APPENDIX O

APPENDIX o
ecocounors

Think about all the creatures with which you share the Earth. What sorts
of insects inhabit your world? What kind of plants grow near your school or
home? How do these organisms interact?

WIth an Ecocolumn you can design bottle habitats for some of the
animals and plants with which you live. You can create homes for spiders,
snails, fruit flies, fungi, and all sorts of microscopic organisms, and many types
of plants. The design possibilities are limited only by your imagination. Before
building your Ecocolumn, brainstorm how to create and maintain habitats that
will support your living organisms. You will need to consider the energy needs
of the organisms, space and shelter needs,and the need for water.

Building the Ecocolumn:

You will need 2 or more two-liter bottles.

Remove the labels from the bottles. NOTE: Soaking the bottles in water
helps in removing the labels or soften glue with a blow dryer.

Cut the top off bottle #1 about 1 cm below shoulder. Cut the bottom off 1
cm below the hip.

Cut top off bottle #2 about 1 cm below shoulder.

Slide A down into B. Tape AIB joint. NOTE: Use clear packing tape or
similar tape which has a width of about 5 cm. If you need a water-tight seal, use
silicone sealant on the joints. Stack chamber AIB on 0.

119

120
Make as many chambers as you need for your stack of habitats. Connect

them by punching holes in the caps and bottle tops. Tape all chambers that will
not be opened.

Reference: Wm Kendall/Hunt, 1993.

APPENDIX P

APPENDIX P

A LEARNING VS. WORK SETTING

 

  
  

      
    

A CONCEPTUAL CHANGE SCIENCE A WORK-ORIENTED SEl'TTNG
LEARNING COMMUNITY
ense-ma Ing an ear mm as e etting the work done as the goal;
goal getting facts learned or activities and
projects completed

 

Personal, emotional involvement in Depersonallzed, unemotional
meaningful and authentic problem relationship with work, getting the

 

 

 

 

 

situations products made

Ownership and commitment by each Teacher as executive In charge of
person; responsibility shared everything

Active inquiry and question-making are Getting the right answer is valued and
valued and encouraged encouraged

Expertise comes from everyone, is Expertise comes from the teacher and
shared; Ieaming is a collaborative Ileaming is a private activity

process

Everyone’s ideas are valued and Workers need to keep quiet and busy;
respected as useful in the Ieaming diversity is a problem for quality control
process; diversity is celebrated in a and efficiency

caring environment

 

 

Good learners listen to each other laced workers listen to the teacher

 

Public sharing and revising (working

Only complete, polished final products
out) of ideas

are shared

 

 

   
  
   
 

Evidence, not authority, is used to
construct new knowledge and judge
merits of ideas

Knowledge comes wrapped in neat
packages that are delivered from
teacher or text to student; all packages
are to be appreciated and not

 

 

Each learner starts and finishes in a All workers create the same product or
unique Place; learning as a process 0t else are failures; Ieaming as a “you
conceptual change have it or you don't” phenomena

From Kathleen J. Roth, (1992).

 

121

APPENDIX Q

APPENDIX 0

9-PATCH QUILT METAPHOR

W has patches that represent for us the various units
we teach in our classrooms-the series of interrelated activities we engage in

with students over time. Each of these patches may look very colorful and
independent, but alone they do not contribute to making a quilt-to helping
students construct understanding--unless they are connected in several ways.

WW Underneath the patches is the batfing, which
provides the substance, the warmth of the quilt. To us, this batting represents

the big ideas and methods of inquiry in the disciplines from which our units are
drawn. If our units are not backed by such important ideas, the patches—the
units made up of activities-will not have any function, any meaning. But the
patches and the depth, the batting, still do not make the quilt.

W The patches and batting are held together
by a backing and by many tiny, intricate “quilting“ stitches. The stitches
represent the qualities of the learning place. Without this backing and the many
tiny, consistent stitches, the quilt would fall apart. It would not only lose its
function, it would lose much of its beauty, for the tiny stitches that go through all
three layers of the quilt to form the beautiful patterns; they are not random. We
think of the backing of the quilt as the learning community in our classrooms
and the stitches as the qualities of the learning setting that are created over time
as students and teachers engage in Ieaming activities together. People visiting
our classrooms need to look for “tiny stitches” to appreciate the qualifies of our
Ieaming environment: The feedback students receive from their teacher on
written work; the encouragement to ask questions and to make sense instead of
just finishing work or memorizing facts; the care put into teacher questions and
activities to communicate sense-making and meaning; the ways in which
student ideas are listened to and brought into the fabric of the classroom; the
encouragement and support students are given to forge new connections and
patterns.

Mixers; The teachers and students are the quilters who work together to
put these patches together patiently over time using consistent, tiny stitches. We
as teachers consistently try to communicate, through our actions and the
activities we choose, that this is a collaborative Ieaming setting.

122

123

W In our metaphor, the warm, finished quilt with its patches
and intricate stitching patterns represents the quality of understandings that
children

develop.

Wm Like many quilters, we are working on our quilt together,
patiently over time. This represents an appreciation of the importance of the
quilting (or learning) process—the interaction, reflection, collaboration-as well
as the finished product. Also like quilters, we are never sure our quilt is finished
completely; we reserve the right to go back and rearrange the patches or
restitch an area. This parallels the tentative nature of knowledge and the need
to revisit and revise our thinking as members of the classroom learning
community.

Reference: Kathleen J. Roth, et. al., The Role of Writing in Creating a Science
Learning Community, Paper presented at the annual meeting of the National
Association for Research in Science Teachers, Lake Geneva, IL, April, 1990.

APPENDIX R

APPENDIX R
ENERGY
Pro-Test and Post Test

MULTIPLE CHOICE Circle the letter of the term of phrase that best completes
each statement or best answers each question.

1. Energy is required for a variety of life processes including
a. growth and reproduction.
b. movement.
c. transport of certain materials across cell membranes.
d. All of the above require energy.

2. Which of the following does not represent a form of energy?
a. light
b. heat
a. water
d. electricity

3. The statement that "energy can neither be created nor destroyed, but can be
changed in form"

a. is not true for all forms of energy.

D. is the first law of thermodynamics.

c. applies only to kinetic energy.

d. is completely untrue.

4. Which of the following situations is the most stable?
a. a boulder on top of a hill
b. a house made out of playing cards stacked on each other
c. three cheerleaders standing on each other's shoulders
d. four tennis balls lying on the ground

5. Heterotrophs are organisms that can
a. produce food from Inorganic molecules and sunlight.
b. survive without energy.
c. consume other organisms for energy.
d. carry out either photosynthesis or chemosynthesis.

124

125

6. The energy that is stored in food molecules and used by organisms
a. resides in the nucleus.
b. is equally distributed among all the atoms' electrons
c. is held primarily by electrons shared by carbon and hydrogen atoms.
d. comes from protons orbiting the nucleus.

7. The sun is considered the ultimate source of energy for life on Earth because
a. all organisms carry out photosynthesis.
b. all organisms carry out cellular respiration.
c. either photosynthetic organisms or organisms that have eaten them
provide energy for all other organisms on Earth.
d. the sun heats the Earth's atmosphere.

8. ATP is called a cell's 'energy currency“ because
a. it catalyzes all metabolic reactions.
b. it allows one organelle to be exchanged for another between cells.
c. all molecules of glucose, a primary source of energy, are made of it
d. most of the energy that drives metabolism is supplied by it.

9. Based on the cycle of photosynthesis and cellular respiration, one can say
that the ultimate original source of energy for all living things on Earth is

a. carbohydrates.

b. water.

c. the sun.

d. electrons.

10. All organic molecules contain carbon atoms that ultimately can be traced
back in the food chain to

a. the bodies of heterotrophs.

b. carbon dioxide from the atmosphere.

0. water absorbed by plants.

d. the carbon that comes from the sun.

11. TIny packets of radiant energy are called
a. photons.
b. protons.
c. eons.
d. electrons.

12. When photons of light strike an object, the light may be
a. reflected.
b. absorbed.
c. transmitted.
d. All of the above may occur.

126

13. What happens when a chlorophyll molecule absorbs a photon of light?
a. Some of its electrons are raised to a higher energy level.
b. It disintegrates, giving off huge amounts of heat.
c. It glows, radiating green light and giving the plant a green appearance.
d. Red and blue wavelengths are emitted.

14. When electrons of a chlorophyll molecule are raised to a higher energy
level

a. they become a photon of light.

b. they form a glucose bond.

0. they enter an electron transport chain.

d. carotenoids are converted to chlorophyll.

15. The source of oxygen produced during photosynthesis is
a. carbon dioxide.
b. water.
c. the air.
d. glucose.

16. All organisms that live in a particular place and their physical location make
up a(an)

a. ecosystem.

b. habitat.

c. community.

d. food chain.

17. An ecosystem consists of
a. a community of organisms.
b. energy.
c. the soil, water, and weather.
d. All of the above.

18. Ecology is the study of the interaction of living organisms
a. with each other and their habitat.
b. and their communities.
c. with each other and their physical environment.
d. and the food they eat.

19. A relationship between a producer and consumer is best illustrated by
a. a snake eating a bird.
b. a fox eating a mouse.
0. a lion eating a zebra.
d. a zebra eating grass.

127

20. In a food web, which type of organism receives energy from every other
type?

a. producer

b. carnivore

c. decomposer

d. herbivore

21. In an ecosystem, the producers may include
a. lions, zebras, and bacteria.
b. trees, grass, and shrubs.
c. vultures, deer, and eagles.
d. bacteria, fungi, and algae.

22. The most abundant organisms in a food chain are the
a. producers.
b. herbivores.
c. carnivores.
d. omnivores.

23. Animals that feed on plants are at least in the
a. first trophic level.
b. second trophic level.
c. carnivores.
d. omnivores.

24. The number of trophic levels in an ecological pyramid
a. is limitless.
b. is limited by the amount of energy that is lost at each trophic level.
c. never exceeds four.
d. never exceeds three.

25. Food webs are more commonplace than food chains because
a. the animals that comprise the links in the food chain are mobile, hence
the chains become intertwined.
b. organisms almost always eat, and are eaten by, many different
organisms.
c. over time food chains always disappear.
d. None of the above.

26. In going from one trophic level to the next higher level
a. the number of organisms increases.
b. the amount of usable energy increases.
c. the amount of usable energy decreases.
d. diversity of organisms increases.

128

TRUE/FALSE Read each statement. If the statement is true, write T in the space
provided. if the statement is false, write F in the space provided.

 

 

 

27. Energy of motion is often referred to as potential energy.

28. __ When a person uses food as a source of energy to run a race, energy
is converted from chemical to mechanical form.

29. The entropy of the universe constantly increases as the energy in the
universe becomes more and more organized.

30. Without enzymes, chemical reactions necessary for life would not
occur at a rate sufficient to sustain life.

31. NAD+ acts as a cell's "energy currency".

32. An autotroph is able to make its own organic molecules from
inorganic materials and energy.

33. Energy moves through food chains from heterotrophs to producers to
consumers.

34. When light hits a plant, all of the wavelengths are absorbed and used

 

to make sugar.

35. Cells that are deprived of oxygen may produce ethyl alcohol and
carbon dioxide through fermentation.

36. Carbohydrates are important parts of an organism's diet because
they are the only molecules that can yield enough energy to produce ATP
during cellular respiration.

 

 

 

 

 

 

 

 

37. All organisms in an ecosystem are part of the food web of that
ecosystem.

38. The source of energy of an organism determines its trophic level.
39. Decomposers absorb energy from organisms by breaking down
living tissue.

40. The lowest trophic level of any ecosystem is occupied by the
producers.

41. Producers are at the bottom of ecological pyramids.

42. A food chain is made up of interrelated food webs.

43. Biomass pyramids can point up or down depending on the
ecosystem.

44. Omnivores feed only on primary producers.

45. The number of organisms in a trophic level Is always directly

proportional to the amount of energy at that level.

SHORT ANSWER Complete each statement by writing the correct term or
phrase in the space provided.

46. is defined as the ability to cause change, or to do work.
47. Energy that is actively engaged in doing work is called work.

48. refers to the level of disorder in the universe.

 

129

49. Organisms that harvest energy from either sunlight or chemicals in order to
make food molecules are called .

 

50. Metabolism consists of the capture, transfer, and use of
within the cells of an organism.

 

51. The ultimate source of energy for all life on Earth is the

 

52. The complete range of radiant energy forms is called the

 

 

 

53. An ecosystem consists of the living and
environment.

54. A path of energy through the energy levels of an ecosystem is called a

 

55. Every time energy is transferred in an ecosystem, potential energy is lost as

 

56. An energy pyramid shows the amount of energy contained in the bodies of
organisms at each level.

57. The sequence of one organism feeding upon another Is called a food chain.
A network of intertwined food chains is called a .

 

CONSTRUCTED RESPONSE QUESTIONS

58. The relationship between photosynthesis and respiration is usually
described as a cycle. Explain why this is true.

59. Green plants need energy to survive and grow. From the list, below, circle
the item(s) which you think are used by green plants as energy for growth and
survival. Explain your answer.

water soil sunlight fertilizer bacteria Insects in the soil

60. Explain why the leaves of plants appear green to the human eye?

130

61. in any given community organisms can be classified as producers,
consumers, and decomposers. Classify each of the organisms listed below as
producers (P), consumers (0), or decomposers (D).

 

 

 

grass (blades & seeds) hawk
soil bacteria __ mouse
mushroom deer
__ earth worm White Cedar tree
coyote ___frog
mosquito Purple Martin bird
bat

 

Assume that the organisms listed above live together in a ecosystem. Show
how energy flows through the community in the space below. Tell what kind of
energy is flowing in your diagram. Include sunlight and heat in your drawing.
Try to include every organism in your diagram.

62. A human needs energy to carry out life functions such as breathing, moving,
or growing. Which of the following is (are) source(s) of energy for human life
functions (check all correct)?

milk
minerals (e.g., iron in Geritol)
hamburger
sunlight striking the skin
heat
___water
sugar

 

 

 

 

 

Select one of the human energy sources above and trace its energy back to Its
ultimate source, showing all the transitions it may have gone through.

Humans get energy from
That energy comes from
which comes from

which comes from . etc.

 

 

 

 

 

What was the ultimate source of energy In this food?

 

131

63. Several years ago John Christopher wrote a gripping science fiction book
called (3mm. in it he described the chaos that enveloped the earth
when a rapidly spreading virus attacked all forms of grass, including all grains
such as wheat, corn, and rice. If we were suddenly faced with destruction of all
forms of the grasses, try to predict what would happen to the human food
supply. Consider the following foods: eggs, cabbage, rice, pork chops, potatoes,
oranges, white bread, cheese, roast beef, tuna. Which of these foods would still
be available in substantial quantities? Why would these foods be available?
Which of these foods would be scarce or non-existent? Explain why each food
that you list would become scarce.

64. Is It good or bad advice to instruct an over-populated country to feed its
peooie beef to supply them with necessary energy? Why or why not?

"It'llililillilililtiilliiil“