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Energy
A. What Is Energy?
1. Does Energy (Light) Have Either Weight Or Volume? 8
2. What Makes It Move? 9
2. Defining Energy? 10
3. How Is Energy / Work Measured? 12
4. How Is the Strength Energy Measured? (The Inverse Square Law) 13
B. Forms of Energy.
1. The Seven Forms Of Energy 16
2. Energy and the Human Body 18
3. Transfer Of Chemical To Heat - Food Burning 23
4. Can Heat Make Things Move? 24
5. Can Chemicals Make Things Move? 26
6. Using A Radio Speaker to Send Your Voice 29
7. Changing Mechanical Energy To Heat Energy 31
8. Energy Conversion Smorgasbord 32
9. Energy Conversion Summary 36
10. Energy Chains 38
C. Types of Energy.
1. Two types of Energy-Potential and Kinetic 40
2. Ah-La-Bounce 41
3. The weight of A Body and Its Gravitational Potential Energy 44
4. Galilean Cannon 46
5. Another Way Of Storing Energy 47
6. Investigating Potential / Kinetic Energy 52
a. Does Potential / Kinetic Energy depend on Force?
b. Does Potential / Kinetic Energy depend on Mass?
D. Conservation of Energy (Energy cannot be Created Nor Destroyed “In Ordinary Circumstances”)
1. Is Energy Conserved When Converted to Work? 57
a. Is Energy Conserved When Force is Changed?
b. Is Energy Conserved When Mass is Changed?
2. Energy Transformations and The Pendulum 59
3. Stop And Go Balls 60
4. Coat Hanger Cannon 63
5. Energy Transformations And The Hand Generator 64
E. Work and Power
1. Determining Your Horsepower? 70
2. Hot Rod Power 72
F. Energy Conversion Game 73
1.
WORKSHOP LEADER TOPIC INFORMATION
INTRODUCTION TO ENERGY
Energy is divided into four subtopics:
1. What is Energy?
2. Forms of energy and conversions
3. Types of Energy - Kinetic and Potential Energy.
4. Conservation of Energy.
The first subtopic examines the meaning of the term "energy," noting that energy is not a "thing," but rather a property that objects can have. It begins with the idea that energy can make something move. The difference between force and energy is discussed, work is defined and a more complete definition of energy as, "the ability to do work" is developed. These concepts are reinforced by examining the energy input and output of the human body.
The second subtopic concerns some of the many forms of energy. In both demonstrations and lab activities, the students are given many opportunities to reinforce the notion that energy is the ability to do work, that energy can be measured, and that one form of energy can be transformed into another form of energy.
The third subtopic concerns potential energy and kinetic energy. Through a variety of activities the factors that affect these kinds of energy are discovered, and for the upper levels the equations of gravitational potential energy and kinetic energy are introduced
The last subtopic explores the concept of energy conservation. Through activities, demonstrations, and discussion, the participants examine the idea that although energy can be transformed the total amount of energy remains the same. The concept of why we could run out of energy even though it is conserved is also addressed. This is followed by a discussion of mass-energy conservation, which is intended as an enrichment topic that can be presented with varying degrees of depth.
While the scope of this book is limited to the 'physics" of energy (which is often not discussed in many other popular materials), it is recognized that the topic has many environmental, economic and social implications. The amount and the forms of energy that we use are now seen to have a direct relationship to how we live our lives. The bibliography contains a sample of some of the many resources that address these issues. Teachers are encouraged to use an interdisciplinary approach to this topic to help their students reach an understanding of the relationship between energy and society.
WORKSHOP PLANNING MATRIX. - FNERGY
Name of
Idea Activity Type Level Duration
I. What is Energy?
A. Energy can make 1. What Makes it Lab LA) 20-25 min.
things move. Move?
B. Energy is the ability 1. Focus on Physics Disc. T 30 min.
to do work. Defining Energy
2. How is Work Lab L/U 30-45 min. Measured?
3. How Much Energy Lab L/U 20-30 min. Do You Use in Climbing a Flight of Stairs?
4. Energy and the Lab L/U 20-30 min. class time
Human Body 24 hr. total time
II. There Are Many Forms of Energy,
A. Some forms of 1. Some Forms Demo L/U 30 min.
energy are: heat, of Energy
light (radiant),
sound, mechanical 2. Can Heat Energy Lab L/U 15 min.
electrical and chemical. Make Things Move?
. 3. Can Chemicals Lab L 25-30 min.
Make Things
Move?
B. Energy can be 1. Energy Chains Lab L/U 20 min. changed from
transformed 2. Energy Lab L/U 15-20 min.
from one form Transformations
to another. 3. Demonstrating Lab L/U 30-40 min. Energy Transformations
C. When energy is 1. Can you Change Demo/ T 20 min.
changed from Mechanical Disc.
one form to Energy to Heat
another, often Energy?
some energy is
changed to 2. Can you Lab L/U 25 min.
heat energy. Change
Mechanical
Energy (motion)
to Heat Energy?
3. Heat Energy Lab L/U 45 min. Smorgasbord
III. Kinetic and Potential Energy,
A. A body may have 1. Focus On Physics: Demo T 25 min.
energy by virtue Potential Energy Disc.
of its position or
condition. This 2. How Do Weight and Lab L/U 25-30 min.
type of energy is Height Affect
called potential Gravitational Potential
or "stored up" energy. Energy?
3. Another Way of Lab L/U 30-45 min. Storing Energy
B. A body may have 1. Focus On Physics: Disc. T 30 min.
energy by virtue of Kinetic Energy
its motion. This type
of energy is called. 2. Do Speed and Mass Lab L 30-40 min.
kinetic energy. Affect Kinetic Energy?
IV. Conservation of Energy
A. Energy can only 1. Energy - Lab L/U 30 min.
be transformed, the. Transformations
total amount of
energy remains the 2. Stop and Go Balls Demo. L/U 15 min.
same. Disc.
3. Energy Lab L/U 30 min. dons and the Hand
Transformation
Generator
4. What is Energy? Disc. T 15 min.
B. Even though the 1. If the Amount of lab L/U 30 min.
total amount of Energy in the Universe
energy in the universe is Constant, Why Must
is constant, it is not We Conserve It?
always in a useful form
C. In special 1. Focus on Disc. T 20 Min.
situations, Like Physics:
nuclear reactions, E=mc2
energy can be converted
to matter, and
matter into energy.
REFERENCES AND RESOURCES
Anderson, F.J. and Freier, G. D., A Demonstration Handbook for Physics, Stony Brook, N. Y.: American Association of Physics Teachers. Second Makin
This publication has a wealth of simple demonstrations from all areas of physics and many that relate to the topic of energy.
Enterprise for Education. Energy 80's, Santa Monica, CA: Enterprise for Education.
Check with your local utility company for this excellent collection of books loaded with ideas and demonstrations in energy education. If the set is not available in your area. write to Enterprise of Education, 1320A Santa Monica Mall, Suite 203, Santa Monica, CA 90401.
Hewitt, Paul. Conceptual Physics. Boston, Mass.: Little, Brown and Company, 5th Edition.
The chapter on energy and the section on heat are good background reading for the workshop presenters. Note in particular, the home projects and exercises for these sections.
Lem, Tick L., Invitations to Science Inquiry. Lexington, Mass.: Ginn Press.
This. book should be in the library of all general science teachers. Many activities and demonstrations are applicable to the topic of energy.
Oak Ridge Associated Universities. Science Activities in Energy, Oak Ridge Associated Universities, assisted by Lawrence Hall of Science.
This is a series of pamphlets available through your local utility company. Illustrated cartoon style, each sheet of activities can be copied and supplied to the students. Highly recommended.
Wilson, Mitchell and the editors of Life, Energy, New York Time, Inc
Part of the Life Science Library, this is an excellent resource for the historical development of energy concepts. Very nicely illustrated and good background reading.
In addition to the references listed above, all of the many elementary-junior high science series produced by various publishers contain projects, activities and demonstrations that the presenter might want to look over to expand the offerings of the workshop.
WORKSHOP LEADER'S PLANNING GUIDE
WHAT IS ENERGY?
Idea A, "Energy can make things move" is a first look at the concept of energy. By investigating toys many questions are raised, such as the difference between energy and force. This introductory activity is also an excellent opportunity for the presenter to determine the students' initial level of understanding of the concept of energy.
Energy is defined in idea B, "Energy is the ability to do work." In this section some activities measuring work will be performed and the units of measure for work and energy are discussed. The metric units used are consistent with current elementary science programs. Activity "Energy and the Human Body" reinforces these concepts and demonstrates the relevancy of energy in everyday life.
The only prerequisite for this topic is an understanding of the metric units of force and distance.
Naive Ideas:
1. The terms "energy" and "force" are interchangeable.
2. From the non-scientific point of view, "work" is synonymous with "labor." It is hard to convince someone that more "work" is probably being done playing football for one hour than studying an hour for a quiz.
A. ENERGY IS THE ABILITY TO MAKF THINGS MOVE.
1. Activity: What Makes it Move?
This activity uses toys to begin to define energy and address the naive idea that "energy" and "force" are interchangeable
B. ENERGY IS THE ABILITY TO DO WORK.
1. Discussion - Focus On Physics: Defining Energy
2. Activity How is Work Measured? The pulling of an object up an incline is used to define work and energy.
3. Activity: How Much Energy do you use in Climbing a Flight of Stairs?
The energy used to climb a flight of stairs is calculated in order to illustrate the joule as the unit of work and energy.
4. Activity: Energy and the Human Body
An attempt to measure the energy input and output of a human body is made in order to show the relevancy of energy in everyday life.
DOES ENERGY HAVE WEIGHT OR TAKE UP SPACE?
Materials: Flashlight or desk lamp, Infant scale, bathroom scale, or lab balance. Measuring cup or graduated cylinder water, Radiometer
PART I: Does energy (light) have weight?
1. Record the reading on the scale.
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2. Predict what will happen when you shine the flashlight on the scale.
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3. Observe the scale very carefully as you shine the flashlight. record the weight.
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4. Experiment by varying the distance of the light from the scale (do not let the flashlight touch the scale!) Try using a stronger source of light.
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5. From your experiment, what can you conclude about energy having weight?
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6. Can you think of any reasons why this experiment might not be a good method of determining whether or not energy has weight?
PART II: Does energy (light) take up space?
1. Fill a measuring cup with water up to the 150 milliliter mark.
2. Shine the flashlight on the water for 5 minutes.
3. Observe the water level very carefully as you shine the light on the water. record any changes in the water level.
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4. Experiment by varying the length of time the light shines on the water. Try using a stronger source of light.
5. From your experiments, what can you conclude about energy taking up space?
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6. Why might this not be a very good experiment to determine whether or not energy takes up space?
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WHAT MAKES IT MOVE?
Materials: Various types of toys that move such as: wind-up toys, cars. trucks, etc), battery operated toys (cars. trucks, etc), air powered toys (balloons, rockets, etc) "gravity operated" toys (balls, yo-yo. etc.)
1. Operate (play with!) the toys at your lab station. Observe what they do. Describe what they have in common.
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2. List each toy and describe what makes it move.
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3. What would you call what makes all of these toys move?
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WHAT MAKES IT MOVE?
IDEA: PROCESS SKILLS:
Energy is the ability to do work. Observing
If an object begins moving, then Communicating work is being done on that object.
LEVEL: TEACHER DURATION: 20-25 min.
STUDENT BACKGROUND: While this first activity does not require any background, it is an excellent
opportunity to determine the backgrounds of the students. Their responses
to the questions will indicate their level of understanding of what energy is
and may also identify many misconceptions about energy.
ADVANCE PREPARATION: Collect an assortment of toys that move. This can be done by asking students to bring in toys. asking friends with children to donate discarded toys, etc. If a toy requires operating instructions, these can be written on cards that can be placed on the tables with the toys. For example, an instruction to "Inflate the balloon (without tying a knot) and release it," would be helpful to show it as a toy that moves.
MANAGEMENT TIPS: The most important elements of this activity are allowing the students to observe and, using the summary discussion, help them formalize what they have observed. It is doubtful that many groups will just come up with the answers suggested below. A more typical answer to, "What makes it move?" for the case of the wind up toy would be "The spring." Follow-up questions by the instructor should lead them to what is in a spring that makes it move. The discussion should offer the opportunity to address the naive idea that the terms "energy" and "force" are interchangeable.
RESPONSES TO
SOME QUESTIONS: 1. They all move.
2. Chemical energy, elastic potential energy, etc.
3. Energy
POINTS TO EMPHASIZE IN
THE SUMMARY DISCUSSION: 1. Energy is the ability to do work. If an object begins moving, then work is being done on that object A more complete definition of work is given in section IB.
2. Energy is not a thing, but rather a property that an object can have.
3. The terms "energy" and "force" are not interchangeable.
POSSIBLE EXTENSIONS: Continue this discussion by observing anything that moves. Discussion can be stimulated by showing pictures of people running, moving cars, sailboats, etc.
FOCUS ON PHYSICS - DEFINING ENERGY
(Discussion)
Discussion "Defining Energy"
Energy is a word like art, love or patriotism. You can think of lots of examples, but it is very difficult to come up with a precise definition. We can get a handle on the problem, however, by defining it in terms of some-thing that can be measured, work. Energy is the ability to do work. (This is an example of an operational definition).
The word work means different things to different people. When used in its scientific sense, it is defined as the product of an applied force on an object and the distance the object moves in the direction of the force, that is:
Work = Force x Distance moved in the direction of the force, or: W = F x d
Forces can be measured with a spring scale in units called Newtons. Distances can be measured with a ruler in meters. Once determining force and distance it is a simple matter to calculate the work that takes place in many situations. The activity that occurs when work takes place is the result of the energy that is transferred from one body to another in the process. The work done is numerically equal to the energy transferred.
Discussion. "Work and Energy Units"
Most upper elementary science programs use the metric system of measurement for their examples and problems. Forces are measured in Newtons and distances are measured in meters. The unit for work, then, is the Newton-meter (F x d). The same unit can also be used for measuring energy.
Scientists decided to honor one of the early investigators of the concept of energy. Sir James Prescott Joule (1818-1889) by giving the Newton-meter a nickname, the joule.
1 Newton-meter = 1 joule
Work and energy, then, can be expressed in Newton-meters, or joules. Some other common units of work and energy are:
kilowatt-hour (kwh) = 3,600,000 joules, used often to measure electrical energy.
calorie (cal) - 4.186 joules
kilocalorie (kcal) = 1000 calories = 4,186 joules. The Caloric used to measure the energy in foods should be written with a capital "C" to indicate that it is really a kilocalorie or 1000 calories. Thus a 1 Calorie diet soft drink is 1 kcal (1000 calories) and a 500 Calorie dessert is 500 kcal (500,000 calories).
An interesting activity is to have a student who travels overseas bring back a "Diet Coke" can from the country they visit. In France, they say 1 kilocalorie, and in Australia, they say "Low Joule Cola?
HOW IS WORK and / or ENERGY MEASURED?
Materials: bricks, board, meter stick, spring scale (that reads in Newtons), object (roller skate or car), string
[pic]
1. Using books or blocks make a ramp with the board as shown in the illustration above.
2. a) Measure the force necessary to pull your object at a constant speed on a flat surface. ____________Newtons
b) Measure the force necessary to pull your object at a constant speed up the ramp. ____________Newtons
c) Measure the force necessary to pull your object straight up (vertical) at a constant speed. ___________Newtons
3. Compare the results and explain ______________________________________________________________________
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4. Measure the distance along the ramp, where the back wheels move as the skate is pulled from the bottom to the top of the ramp. (i.e. measure the distance from the back wheels at the bottom of the ramp to the back wheels at the top of the ramp.)
METERS ___________
5. Calculate the work done in pulling the object up the ramp.
WORK = FORCE x DISTANCE ______Joules = _______Newtons x ________meters
6. Calculate the work done in lifting the object the same distance vertically as it was previously raised by pulling it up the ramp.
WORK = FORCE x DISTANCE ______Joules = _______Newtons x ________meters
7. Compare the work done in pulling the object up the ramp to the work done lifting the object the same distance vertically.
Work done in pulling the object up the ramp. __________Joules
Work done in lifting the object vertically. __________Joules
Explain why there is a difference in the values of Joules.
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HOW IS WORK MEASURED?
IDEA: PROCESS SKILLS:
Energy is the ability to do work. Predict Compare
LEVEL: TEACHERS DURATION: 30-45 min.
STUDENT BACKGROUND: Students should be familiar with the metric system, and that the Newton is the unit of force.
ADVANCE PREPARATION: If this is to be a small group activity, you might ask several days before the scheduled class for the students to bring in old roller skates and bricks. Other toys that have relatively low friction wheels can be substituted for the roller skates, and other heavy objects can be used instead of bricks. The idea is to keep the object to be pulled within the range of the spring scale. (When measuring the total weight of the skate and brick, each can be weighed separately and then add the two values added. Tie a string around the brick to attach it to the spring scale.) An alternative to using boxes is to use plastic film cans filled with sand (as used in IIA2). These can be placed inside the track that the cars run in and the distances the cars move can be measured with the meter sticks.
MANAGEMENT TIPS: Use caution handling bricks. This is not intended to be an exercise in how the inclined plane is a simple machine, but rather an activity to illustrate how work and energy are measured. The meter sticks should be placed just a little farther apart then the width of the cars to ensure that the cars travel in a straight line.
RESPONSES TO
SOME QUESTIONS: 4. (Work) joules = (Force) Newtons x (distance) meters.
7. It will probably not be obvious, but they should be the same. Discuss this with the class, pointing out that in reality, pulling the skate and brick up the ramp may require more work due to friction. See the book "SIMPLE MACHINES" for more detail.
8. (Work) joules = (force) Newtons x (vertical distance) meters.
POINTS TO EMPHASIZE IN
THE SUMMARY DISCUSSION: 1. Only the force in the direction of the distance moved is used in calculating work.
2. The work done is numerically equal to the energy expended.
INVERSE SQUARE LAW
The intensity or strength of most types of energy (such as light, sound, gravity, electricity, and magnetism) diminishes as we move away from the source. We have all seen the pattern created when a flashlight's beam spreads out as it is moved further from a wall in a darkened room. The changing intensity of this pattern is described by the Inverse Square Law.
The Inverse Square law indicates that the intensity (or the strength) of a magnetic field varies inversely with the square of the distance from the magnet. This means that if the distance (d) increases, the intensity (I) decreases by the square of the distance from the source (i.e. I is proportional to 1/d2 ).
You will use a laser for this investigation that is a brilliant laser designed to last and is the next generation in real optical laser diodes so powerful it can be seen up to 1500 feet away! Designed in Germany and manufactured to the highest quality standards. DO NOT point the laser beam into the eyes of humans or pets.
Experiment
1. Place the “attachment” over the end of the laser. The “attachment is made from a piece of PVC pipe cut approximately 2-5-cm long. This pipe has a piece of double diffraction grating glued on it.
2. Hold the laser 1 meter as indicated in the table and shine on a flat surface. You will notice squares reflecting on the surface. Select one of the squares and draw it on the surface.
3. Hold the laser 2 meters from the surface. Align the same square with one side and bottom. Determine the number of original squares it would take to fill the larger square.
4. Hold the laser 3 meters from the surface. Align the same square with one side and bottom. Determine the number of original squares it would take to fill the larger square.
5. Compare the data and look for relationships.
|Distance |1-Meter |2-Meters |3-Meters |
|Number of Squares |1 | | |
|Distance Squared (D) | | | |
|1/Distance2 ∞ (Intensity) | | | |
WORKSHOP LEADER'S PLANNING GUIDE
THERE ARE MANY FORMS OF ENERGY
This subtopic is easy to present. and the workshop leader will have little difficulty eliciting the names of the various forms of energy from the teacher's personal experiences. As each form is identified, it is shown to be a source of energy by its ability to do work (sub topic 1, idea B). Several more demonstrations and activities are performed to show that energy can be changed into heat. The ideas presented in subtopics I & II an the prerequisites for this subtopic.
Naive Ideas:
1. Things "use up" energy.
2. Energy is confined to some particular origin, such as what we get from food or what the electric company sells.
A. Some forms of energy are heat light (radiant) sound. Mechanical, electrical chemical ant) nuclear
1. Demonstration: Some Forms of Energy.
This demonstration uses a variety of objects to clarify the variety forms that energy lakes.
2. Activity: Can Heat Energy Make Things Move?
Certain types of candy wrappers and a light bulb are used to show that heat is a form of energy.
3. Activity: Can Chemical Energy Make Things Move?
Baking soda and vinegar are used to show that chemicals can contain energy.
B. Energy can re changed from one form to another.
1. Demonstration: Energy Chains. Everyday objects are used to trace energy flow from one form to another.
2. Activity: Energy Transformations. A matrix is used to illustrate energy transformations.
3. Activity: Demonstrating Energy Transformations Several different activities with speakers illustrate energy transformations.
C. When energy is changed from one form to another often some energy is changed to heat energy.
1. Demonstration/Discussion: Can You Change Mechanical Energy to Heat Energy? Three different ways to demonstrate the transformation from mechanical energy to heat.
2. Activity: Can You Change Mechanical Energy (motion) to Heat Energy? Shaking sand in styrofoam containers illustrates the transformation from kinetic energy to heat energy.
3. Activity: Heat Energy Smorgasbord. This activity contains five short labs showing heat energy resulting from energy transformations.
4. SOME FORMS OF ENERGY
(Demonstration)
Energy was defined as the ability to do work. If an object begins moving, then work is being done on it, and therefore, some form of energy is being used. We refer back to this idea to demonstrate some of the many forms that energy can take. It is suggested that a list of energy forms be generated by the students. Examples of each form can be taken individually and demonstrated to show its ability to make something move. As each is shown, the objects are placed on a table with a card labeling that form of energy. For example if a student mentions coal, a demonstration of how chemical energy causes motion can be shown. If another student mentions gasoline the instructor can point out that it is another form of chemical energy. The objective of this demonstration is to make similarities and differences between the many forms of energy "come alive" to focus discussion. It is not intended as an attempt to classify every form of energy in the universe. Some suggestions arc as follows:
1. Heat: Heat a bimetallic strip with a match or candle flame. Ask "Does heat make things move? Is heat a form of energy?"
Another example of heat to motion that might be used is the form of the pin wheel found in Christmas ornaments that makes use of the convention currents from candles to produce rotation, or a "palm glass" that uses heat from a person's hand to partially evaporate a colored liquid causing the remaining liquid to be forced up a glass tube..
2. Light: Start a radiometer moving with a flashlight. If a flash attachment from a camera is available, try "kick" starting the radiometer with the flash. For each of the forms of energy, ask:
Does _____________ make things move?
Is ________________ a form of energy?
3. Sound: A sound apparatus that consists of a tin can, a balloon and a small mirror that will demonstrate that sound can cause something to move. Another example would be to use two matched tuning forks (preferably mounted on sounding boxes). Striking one fork will cause the sound from it to set the other one in motion.
4. Mechanical: This type of energy is the kinetic and potential energy of objects. There are a variety of toys that can be used here to demonstrate mechanical energy.
5. Electrical: Hold up the plug to an electric fan and ask "What form of energy are we dealing with here?" (Electric). Plug in the fan and turn it on. As an alternative. use a battery operated toy. Show the battery first and ask the same question as you would with the plug. Insert the battery and make the toy move. (If a battery
is used, then it is stored chemical energy, not electrical energy).
6. Chemical: Half fill a test tube with vinegar. Put about Sec (or about half a teaspoon) of baking soda into a rubber balloon. Attach the end of the balloon to the top of the test tube and shake the baking soda into the vinegar. The gas produced (CO2) will make the balloon expand (Stretching the balloon first by blowing it up and releasing the air will make this more dramatic.) A variation of this example is to place a few drops of water into the bottom of a plastic 35mm film can and drop in an "Alka-seltzer" tablet and quickly snap on the lid. Place the can on the table in such a way that the lid will not hit anyone when it pops off.
7. Nuclear: Use a Krieger counter in listen to background radiation. Hold the Geiger tube near a piece of ordinary rock and note that the background activity remains the same. Now hold the tube near a radioactive sample. Now the sharp increase in activity, both) by the speaker and the deflection of the meter needle. This may seem kind of far-fetched, but it does make an impression on the viewers that indeed, nuclear energy does make things move.
SEVEN FORMS OF ENERGY
1. Heat
2. Light
3. Sound
4. Mechanical
5. Electrical
6. Chemical
7. Nuclear
ENERGY AND THE HUMAN BODY
Materials: chart, "Calories Burned Per Hour", chart, "Calorie Content in Common Foods" log sheets
Energy is used in the human body to do work internally as well as externally. Internally, energy is used for all of the many processes that keep us alive such as respiration, circulation, digestion, etc. Externally, energy is what allows us to do work on our body as a whole such as in climbing up stairs, or to do work on other objects such as when throwing a baseball. The body gets its energy from food (chemical energy see p 23). The purpose of this activity is to become acquainted with energy and its units by attempting to measure energy that is put into your body in a day and comparing it to what is used. This activity simplifies some of the calculations that must be made to regulate your body's food intake for health regulations and is not intended for use as a nutrition guide. For more complete information consult a Registered Dietician.
1. Using the log sheets supplied below, keep track of everything you eat in a 24 hour period. Beside each type of food list the number of Calories it contained by referring to the chart "Calorie content in common foods" (page 20-21).
2. On the same log sheets record each and every activity you do and note for how long you do it. Beside each activity list the amount of calories used up in the activity by referring to the chart "Calories burned per hour" (page 19). If the activity you did is not listed, pick the calories burned from an activity that you think requires about the same amount of energy. (Note: The numbers on this chart include both the external energy to do the activity and the internal energy to keep a person alive.)
3. What was the total number of Calories you took in during this period? ___________ Calories
4. Convert this amount of energy from Calorie units to joules, remembering that a Caloric used by dieticians is really a kilocalorie which is 4,186 joules.
calories x 4186 joules per calorie = joules
5. Calculate your weight in Newtons (one pound is approximately 4.5 Newtons)
Weight in pounds x 4.5 Newtons per pound = Newtons
6. The energy calculated in 4 is the amount of work this food can do. If all of this work went into climbing a mountain, calculate how high you could go. (Note: since Work = Force x Distance; Distance = Work/Force. The force required to pick yourself up is your weight)
Distance = Work / Force _______ meters = _______ joules / ________Newtons
7. Compare the height you calculated to the height of Mt. Everest which is approximately 8850m. Do you think you could really climb this high using the food energy you ate during a 24 hour period? For what else must your food energy be used?
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8. According to the estimates on your log sheets, what was the total number of Calories you used during this 24 hour period?
Calories
9. How does the amount of energy you put into your body during this period (step #3) compare to the estimate of the amount that you used? If there is a difference, what do you think this will cause?
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10. A net gain or loss of 7700 Calories from your diet represents a gain or loss of 1 kilogram of body mass (or about 2.2 pounds of weight). Did you gain or lose mass during this period? If so, calculate how much.
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CALORIES BURNED PER HOUR
(Body mass in kilograms)
ACTIVITY 50 60 70 75 85 100
Backpacking 400 470 540 600 690 770
Basketball 415 485 565 635 715 800
Canoeing 130 155 180 205 230 260
Climbing 360 420 485 550 620 710
Crew 310 365 420 475 535 600
Cycling (Leisure) 240 265 305 365 420 480
(Racing) 510 600 690 780 870 980
Dancing (Slow) 155 180 210 235 265 295
(Fast) 310 365 420 475 535 600
Fishing 185 220 255 290 320 365
Gardening (Mowing) 355 395 455 515 575 655
(Digging) 375 445 515 580 650 730
Golfing 260 300 350 390 440 500
Gymnastics 280 315 360 405 455 515
Horseback riding 200 235 270 305 340 390
Ironing 100 115 130 150 170 190
Judo/Karate 585 690 795 900 1005 1145
Mopping 185 220 250 285 320 365
Painting 135 185 220 245 280 305
Playing Piano 120 145 165 190 210 240
Running (10 min/mile) 360 450 530 600 650 730
(9 min/mile) 580 685 785 895 995 1135
(8 min/mile) 650 750 850 960 1060 1200
(7 min/mile) 730 835 936 1040 1145 1285
(6 min/mile) 835 935 1035 1145 1245 1385
(5 min/mile) 870 1025 1180 1335 1490 1695
Shopping 185 220 250 285 320 365
Sitting 65 70 85 95 110 125
Skating (Ice) 255 295 345 385 435 485
(Roller) 270 305 355 400 445 510
Sking (Moderate) 330 375 430 480 545 620
(Maximum) 540 730 850 1005 1105 1260
Skin Diving 620 730 840 955 1060 1210
Sleeping 60 65 80 90 100 110
Swimming (Slow) 385 455 520 595 660 750
(Fast) 470 550 635 720 805 920
Tennis 335 385 445 505 565 645
Typing 85 95 110 125 140 155
Volleyball (6 person) 185 225 260 295 320 355
Walking 240 285 325 360 395 450
Weight Training 560 665 755 850 955 1085
ENERGY CALORIE CONTENT IN COMMON FOODS
MEAT
Cheese, Cheddar 114 Cornbread 191
Bacon 92 slice 2 1/2"x3". enriched
2 slices Cheese, Cottage 109 Cornflakes 72
Beans, Refried 142 12 cup 3/4 cup
1/2 cup Cheese, Monterey 1 06 Crackers, Saltines 6 0
Beef, Ground 186 slice 5
3 oz. Cheese, Mozzarella 106 Hominy Grits 6 2
Beef, Roast 18 2 (pan skim) slice 1/2 cup, enriched
3 oz. Cheese Spread 82 Macaroni 78
Beef Liver 195 1 oz. 1/2 cup, enriched
3 oz. Cheese, Swiss 107 Noodles, Egg 100
Bologna 8 6 slice 12 cup, enriched
slice Cocoa 164 Oatmeal 66
Chicken, Fried 201 3/4 cup 1/2 cup
leg and thigh Ice Cream, Vanilla 135 Pancake 61
Egg, Fried 8 3 12 cup 4' diameter, enriched
large Ice Milk, Vanilla 112 Raisin Bran 144
Egg, Hard-Boiled 7 9 1/2 cup, soft serve 1 cup, enriched
large Milk 150 Rice 112
Egg-Scrambled 95 1 cup 12 cup
large Milk, Chocolate 208 Roll, Frankfurter 119
Frankfurter 172 I cup enriched
2 oz Milk, Lowfat 2% 121 Roll, Hamburger 119
Ham, Baked 179 1 cup enriched
3oz Milk, Lowfat 1% 102 Roll, Hard 156
Meat Loaf 2 3 0 I cup enriched
3 oz. Milk, Skim 8 6 Toast, White 6 1
Peanut Butter - 186 1 cup slice
2 tbsp Milkshake, Chocolate 356 Tortilla, Corn 63
Peanuts 211 10.6 oz. 6". enriched
1/4 cup Pudding, Chocolate 161 Waffles 130
Peas, Blackeye 9 4 1/2 cup 2. enriched
12 cup. dried Yogurt, Plain 144
Perch, Fried, Breaded 193 1 cup FRUIT • VEGETABLE
3 oz Yogurt, Strawberry 255
Pork Chop 308 1cup Apple 80
3 oz. Yogurt, Vanilla 194 medium
Sausage 135 1cup Banana 101
2 pork links medium
T-Bone Steak 212 GRAIN Beans, Green 16
3 1/3 oz. 12 cup
Tuna 168 Bagel 165 Broccoli 20
3oz Biscuit 103 12 cup
enriched Cantaloupe 29
MILK Bread, Rye 6 1 1/4 medium
slice Carrot Sticks 21
Bread, W bite 6 1 5" carrot
Buttermilk 99 slice, enriched Coleslaw 82
1cup Bread, Whole Wheat 5 5 12 cup
Cheese, American 106 slice
CALORIE CONTENT IN COMMON FOODS
Corn 7 0 Gravy, Beef 3 1 FAST FOODS
1/2 cup 1/4 cup
Grapefruit, Pink 4 8 Jelly, Currant 49 Burger King's
1/2 medium 1 tbsp Whopper 670
Orange 65 Maple Syrup 50 Dairy Queen's
medium 1 tbsp Brazier Dog 280
Orange Juice 56 Mayonnaise 101 Kentucky Fried Chicken's
1/2 cup 1 tbsp Original Recipe Dinner 643
Peaches 100 Pie, Apple 403 McDonald's Big Mac 563
1/2 cup 1/6 of 9" pie McDonald's
Pear 101 Popcorn, Unbuttered 23 Cheeseburger 307
medium 1 cup McDonald's
Peas, Green 5 4 Potato Chips 114 Egg McMuffin 327
1/2 cup 10 chips McDonald's
Potato, Baked 132 Roll, Danish Pastry 274 Filet-0 Fish 432
Large Sherbert, Orange 135 Pizza Hut's
Potatoes, French-Fried 233 1/2 cup Supreme Pizza 5 10
20 pieces Soft Drink, Cola 9 6 3 slices
Potatoes, Mashed 63 1 cup Taco Bell's
12 cup Sugar 14 Bean Burrito 343
Raisins 123 1 tsp 412 tbsp
Tomato 22 COMBINATION FOODS
1/2 medium
Tossed Salad 13 Bake Beans with Pork 156
3/4 cup 1/2 cup
Watermelon 5 2 Beef Potpie 388
1 cup 1/4 of 9" pie
Beef & Vegetable Stew 209
OTHERS 1 cup
Chicken Chow Mien 255
Butter or margarine 3 6 1 cup
I tsp Chili Con Carne
Cake, chocolate 234 with Beans 333
1/16 of 9" cake 1 cup
Cake, Sponge 196 Lasagna 633
1/12 of 10" cake 2 1/2" x 4 1/2"
Candy Bar, Chocolate 147 Macaroni and Cheese 215
I oz. 1/2 cup
Chocolate Syrup 93 Pizza, Cheese 354
2 tbsp 1/4 of 14" pie
Coffee, Black 2 Soup, Chicken Noodle 5 9
3/4 cup cup
Cookie, Sugar 89 Soup, Tomato 173
3" diameter I cup
Doughnut, Cake Type 125 Spaghetti w/Meal Bails 332
French Dressing 66 1 cup
1 tbsp Taco, Beef 216
Gelatin 71
1/2 cup
ENERGY AND THE HUMAN BODY
IDEA: PROCESS SKILLS:
Energy is important in everyday life. Measuring Interpreting Data
LEVEL: Teacher notes DURATION: 24 hr 20-30 min. (class time)
STUDENT BACKGROUND: The complete activity requires that students are familiar with work and how it is measured. If students lack this background, eliminate numbers 4-7 of the activity.
ADVANCE PREPARATION: introduce the activity and pass out log sheets, "Calorie Burned per Hour" chart and "Calorie Content in Common Food" chart early enough to allow the students the 24 hours required to collect the data. Students may need extra copies of the log sheets and may need to be shown how to calculate the Calories for an activity that is not an even number of hours. (e.g. 400 Calories burned per hour x 1.25 hours = 500 Calories.)
MANAGEMENT TIPS: It is important to remember that the purpose of this activity is to become acquainted with energy and its units by looking at how the human body uses energy. This activity simplifies some of the calculations and does not consider that good nutrition is much more than merely a matter of calories. Therefore, it is important to emphasize the activity is not accurate enough to use for health reasons and is not intended as a nutrition guide. For more complete information consult a Registered Dietitian.
RESPONSES TO
SOME QUESTIONS: 4. If the person ate 2500 Calories:
2500 Calories x 4146 joule per Calorie = 10,465,000 joules
5. If the person weighed 150 pounds: 150 pounds x 4.5 Newtons per pound = 675 Newtons
6. Using a 675 Newton (150 lb) person who eats 10,465,010 joules (2500 Calories):
15,504 meters . 10,465.000 joules / 675 Newtons
7. No. Much of the energy used must go into internal energy.
9. I used less (or more) energy than I took in. This will cause me to gain (or lose) mass.
10. If a person used 1000 Calories less than he or she took in then the gain in mass would be:
1000 Calories/ 7700 Calories per kilogram = .13 kg (.13 kg on earth weighs about .29 lb)
POINTS TO EMPHASIZE IN
THE SUMMARY DISCUSSION: A large amount of energy we use is required for internal life processes. The amount varies from person to person depending on a variety of factors, which is one of the reasons that the numbers used in "Calories Burned Per Hours" chart are only rough estimates. Typically only about 15-30% of the energy input is used for voluntary muscular activity.
POSSIBLE EXTENSIONS: 1. It is an interesting activity to try to use the "Calories Burned Per Hour" chart to plan a day that would use exactly the amount of calories ingested. Remember to include all of the activities in a 24 hour period since this is the amount of time you kept track of your food intake.
2. A similar activity could be devised using the energy input and output of an automobile.
TRANSFORMATION OF CHEMICAL ENERGY TO HEAT ENERGY
Problem: How do we determine the number of calories present in food?
[pic]
1. Obtain one half of a peanut, determine its mass (m) in grams, and place the peanut on the pin in the cork.
2. Fill the test tube with 25.0 ml. of water. Record its mass (Mwater) and temperature (T1).
(25.0 ml of water has a mass of 25.0 grams).
3. Light the peanut with a match, and place the test tube over the flame.
4. When the peanut finishes burning, record the temperature of the water (T2). Calculate the change in temperature (∆T) by subtracting T1 from T2. ∆T = T2 – T1
5. Assuming all the energy in the peanut was transferred to the water, calculate the number of calories in the peanut by multiplying the mass of the water by the temperature change. H = Mwater x ∆T
6. Determine the number of food Calories in the peanut by dividing the number of calories by one thousand.
7. Repeat the process for a different food sample, and record the data in the space provided.
DATA TABLE
| |Sample A - Peanut | Sample B - |
|1. mass of material (g) | | |
|2. mass cold water (Mwater) | | |
|3. Temp. cold water (T1) | | |
|4. Temp. heated water (T2) | | |
|5. Temp. chg. of water (∆T) | | |
|6. calories (H) | | |
|6. calories | | |
CAN HEAT ENERGY MAKE THINGS MOVE?
Materials: chewing gum wrapper (foil/paper combination) scissors, source of heat (incandescent light bulb) and socket
1. Cut a strip from the wrapper .5 centimeters wide and 6 centimeters long.
2. Hold the strip, slimy side down, over the glowing bulb. Observe what happens.
3. Describe what happened to the strip.
4. Explain how this demonstrates that heat is a form of energy.
5. Predict what will happen if the strip is removed from the source of heat and placed in a cool spot near a window or in a refrigerator.
| |
6. Check your prediction in Step 5 by moving the strip from a source of heat to a much cooler area.
7. Experiment by using a piece of paper the same dimensions as the strip cut from the wrapper.
Does the heat from the bulb make the paper move? _____________
Try a strip cut from aluminum foil. Does the heat from the bulb make the foil move? __________________________
8. Explain why the gum wrapper was a better detector of heat than the paper or aluminum foil.
| |
| |
CAN HEAT ENERGY MAKE THINGS MOVE?
IDEA: PROCESS SKILLS:
To show that heat energy is truly a form Observing
of energy Predicting Inferring
LEVEL: TEACHER DURATION: 15 min.
STUDENT BACKGROUND: Students should know that energy makes things move.
ADVANCE PREPARATION: The type of wrapper paper needed is-the kind that has a thin layer of aluminum bonded to paper. This type of wrapper can also be found on "Hershey's" miniature chocolate bars. Several snips can be cut from each wrapper.
MANAGEMENT TIPS: Have the students use caution with the scissors, as well as with the hot bulb.
RESPONSES TO
SOME QUESTIONS: 3. The snip bends away from the light bulb.
4. Energy makes things move. Energy is the ability to do work. The heat from the bulb does work on the strip.
5. It straightens out.
7. No, No.
8. The aluminum side of the paper expands more than the paper side, causing it to bend.
POINTS TO EMPHASIZE IN
THE SUMMARY DISCUSSION: 1. Energy makes things move.
2. The heat from the lamp did work on the snip, causing it to bend. POSSIBLE EXTENSIONS: Bimetallic strips used in thermostats are dial-type thermometers.
CAN CHEMICAL ENERGY MAKE THINGS MOVE?
Objectives:
1. Collect measurement data for class discussion using the Alka-Poppers.
2. Identify the conversion of chemical energy to mechanical energy.
Introduction:
An Alka-Poppers is made by placing water and part of an Alka-Seltzer tablet in a film container and then placing on the cap. The gas given off by the Alka-Seltzer builds up enough pressure to pop the cap.
Materials: 1 film container, 10 ml graduated cylinder, clock with second hand, 1 package of Alka-Seltzer tablets, thermometer, triple beam balance, English/ metric measuring device
Procedure: (Work with one or at most two partners)
1. Open your packet of Alka-Seltzer tablets and determines the mass (weight) of one tablet. Carefully break each tablet into four pieces. Determine the mass (weight) of one of the 1/4 tablet pieces.
2. Record the temperature of the water.
3. Place 1/4 of an Alka-Seltzer tablet into the film container with 8.0 ml. of water and immediately place the lid on the container. Note: Replace the Alka-Seltzer when there is no longer enough gas to make the cap pop.
4. Record the temperature of the water after the explosion and calculate the change in temperature due to the explosion.
5. Obtain the average distance the cap goes using three trials. (Try to get the greatest distance)
6. Obtain the time to pop the cap for three trials and determine the average.
7. Using 1/2 of an Alka-Seltzer tablet estimate the number of explosions that would occur in one minute then actually perform the experiment.
Data:
| |¼ tablet |½ tablet |¾ tablet |
|1. (1) |Mass | | | |
|2. (2,4) |Temperature | | | |
|3. (5) |Distance: |1 | | | |
| | |2 | | | |
| | |3 | | | |
| | |Av. | | | |
|5. (6) |Time to explode |1 | | | |
| | |2 | | | |
| | |3 | | | |
| | |Av. | | | |
|6. (7) |Number of explosions | | | | |
Conclusion: (summarize what you have done and what you have learned concerning this activity)
_________________________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
CAN CHEMICAL ENERGY MAKE THINGS MOVE? - Alternate
Materials: soda bottle, small balloon, piece of string, vinegar, baking soda, graduated cylinder balance
1. Measure 60 milliliters of vinegar and pour into the soda bottle.
2. Measure out 7 grams of baking soda and place it into the balloon.
3. Put the neck of the balloon over the top of the bottle, being careful not to let the baking soda fall into the vinegar.
4. Tie a string around the necks of the balloon and the bottle to keep the balloon from "popping off."
5. Raise the balloon to allow the baking soda to fall into the vinegar.
6. Observe what happens as the baking soda mixes with the vinegar.
7. Describe what happened
8. Explain how this experiment demonstrates that chemicals are a source of energy.
CAN CHEMICAL ENERGY MAKE THINGS MOVE?
IDEA: PROCESS SKILLS:
To show that chemical energy is truly Observing
a form of energy Inferring
LEVEL: TEACHER DURATION: 25-30 min.
STUDENT BACKGROUND: Students should know that energy makes things move.
ADVANCE PREPARATION: All of the materials are easy to gather. The amount of vinegar and baking soda can be estimated if graduated cylinders and balances are unavailable.
MANAGEMENT TIPS: Pre-stretching the balloon by blowing it up and releasing the air will make it easier for the gas from the reaction to inflate the balloon.
RESPONSES TO
SOME QUEST1ONS: 7. The mixture starts to bubble and the balloon inflates.
8. Mechanical reaction produces a gas (carbon dioxide). The gas does work on the walls of the balloon.
POINTS TO EMPHASIZE 1N
THE SUMMARY DISCUSSION: 1. Energy makes things move.
2. The gas produced as a result of the chemical reaction did work on the balloon.
POSSIBLE EXTENSIONS: The expanding gases in an automobile engine as a result of the explosions in the cylinders.
USING A RADIO SPEAKER TO SEND YOUR VOICE
-
Materials: 2 radio speakers, 2 30 cm lengths of stranded wire with alligator clips on each end, 1 galvanometer, 1 flashlight battery (1.5 volts, any size), 5 meters of #I8 lamp cord (alligator clips on each end)
1. Use the alligator clips to connect the two wires to the two tabs on one of the radio speakers. Hold the clip on the other end of one of the wires, to either end of the flashlight battery. Tape the end of the second wire on to the other end of the battery. Observe the speaker.
2. Describe what happened.
3. Identify the energy transformations that took place.
4. Return the battery to the teacher and obtain a galvanometer. A galvanometer is a very sensitive meter that will indicate a tiny electric current by the motion of its needle. Connect the loose ends of the two wires on the speaker to the two terminals on galvanometer.
5. Very acidly touch the center of the paper cone of the speaker. Press it very lightly several times. Observe the meter.
6. Describe what happened.
7. Identify the energy transformations that wok place.
8. Experiment by shouting into the radio speaker and observing the galvanometer. Identify the energy transformations that took place.
9. Connect a speaker to each end of the long piece of lamp cord. If possible, try to have one of the speakers in the next room or in the corridor with the door closed as much as possible without breaking the wire.
10. Hold one of the speakers up close to your ear as a classmate talks into the other speaker. The person doing the talking may have to cup their hands around the speaker to funnel the sound directly onto the cone. Repeat the procedure except this time, you talk into the speaker while the other person listens.
11. Identify the links of the energy chain related to this experiment
USING A RADIO SPEAKER TO SEND YOUR VOICE
IDEA: PROCESS SKILLS:
Energy can be changed from one form Classifying
to another. Experimenting
LEVEL: TEACHER DURATION: 30-40 min.
STUDENT BACKGROUND: Students should be familiar with the different forms of energy and know that energy can be changed from one form to another.
ADVANCE PREPARATION: Several weeks before this activity, have the students bring in old or discarded radios from home. Very carefully remove the speakers trying not to puncture the paper cones. Miniature speakers can also be purchased for several dollars from an electronics store, such as Radio Shack.
MANAGEMENT TIPS: Caution the students not to press too hard on the paper cones or to puncture them by improper handling.
RESPONSES TO
SOME QUESTIONS: 2. The speaker "clicks" each time the wire is tapped on the battery.
3. Electrical- mechanical - sound.
6. The needle on the meter moves back and forth when the cone is pressed
7. Mechanical - electrical (to mechanical once again as the needle moves).
8. Sound - mechanical - electrical - mechanical.
11. Sound - mechanical - electrical - mechanical - sound.
POINTS TO EMPHASIZE IN
THE SUMMARY DISCUSSION: 1. Mechanical energy can be changed to electrical energy.
2. Electrical energy can be changed to mechanical energy and sound.
3. Sound energy can be changed to mechanical energy, which can be changed to electrical energy, which can be changed back to mechanical energy and back to sound.
POSSIBLE EXTENSIONS: Discussion of how microphones work.
Experimenting with string telephones (two cans connected by a string).
CAN YOU CHANGE MECHANICAL ENERGY
TO HEAT ENERGY?
(Demonstration/Discussion)
Drop a ball and watch as the bounces get progressively smaller. What is happening to the energy of the ball?
Where does it go?
Pound a block of wood with a hammer several times.
What happened to the kinetic energy of the hammer as it struck the wood?
To answer these questions, we must look at one of the most prevalent forms of energy, heat energy.
What is commonly called heat energy is related to the several kinds of internal energies that the molecules of a substance may have. One type of internal energy that molecules can have is kinetic energy. A thermometer is a device that allows us to measure the average kinetic energy of the molecules of a body, and thus, its temperature. For a given object, the higher the temperature the more heat energy it contains.
In the case of the bouncing ball, some of the energy was lost as sound, and some was lost in the form of heat energy. Both the molecules of the ball and the molecules in the floor had their kinetic energy increased upon impact, thus raising the temperature a tiny amount. This is also true of the hammer pounding on wood.
Some demonstrations illustrating the transformation of mechanical energy to heat energy are as follows:
a. Pound a nail into a block of wood and pull it out. Feel the nail. Its hot.
b. Drill a hole into a piece of hard wood such as oak or maple. The drill bit and the shavings get hot, (Be careful! The drill bit can get very hot)
c. Beat upon a piece of hard wood with a hammer and very quickly place a sheet of temperature sensitive liquid crystal material over the spot. Note the color change indicating a rise in temperature. (Relatively inexpensive thermometers made of liquid crystal are available in drug stores and will work with this demonstration.)
d. Materials: 2 styrofoam cups strong tape, thermometer fine dry sand
1. Fill one cup about 1/3 full of sand.
2. Very carefully. insert the bulb of the thermometer into the sand, wait about two minutes and record the reading on the thermometer.
__________degrees
3. Remove the thermometer, invert the second cup over the first, and seal well by wrapping the tape around the seam between the two cups. Vigorously shake the sand back and forth inside the cups. Continue shaking for five minutes, passing the bottle among the members of your group.
4. After the five minutes are up. carefully punch a hole in the top of the container and insert the thermometer into the sand. Record the temperature.
__________degrees
5. Compare the two temperature readings. Record the difference in temperature.
__________degrees
6. Explain what you had to do to the bottle of sand to raise its temperature.
CAN YOU CHANGE MECHANICAL ENERGY
(MOTION) TO HEAT ENERGY?
IDEA: PROCESS SKILLS:
When energy is changed from one form to Measuring
another, in most cases, some energy is Experimenting changed to heal
LEVEL: TEACHER NOTES DURATION: 25 min.
STUDENT BACKGROUND: Students should be familiar with the forms of energy, and understand that energy can change from one form to another.
ADVANCE PREPARATION: Check on sources of sand, such as pet shops (aquarium sand), the heath, etc.
MANAGEMENT TIPS: Make sure cups are tightly fastened. Have the students use care when inserting the thermometer into the sand.
RESPONSES TO
SOME QUESTIONS: 4. The temperature should be higher.
6. The student had to do work on the sand to raise its temperature.
POINTS TO EMPHASIZE IN
THE SUMMARY DISCUSS1ON: 1. Mechanical energy can be transformed to heat energy.
2. Work had to be done on the sand to raise its temperature.
ENERGY SMORGASBORD
Materials: elastic bands, hand drills, nails, block of wood, hammer, pieces of coat hangers, cap for 3/4 copper tubing, superball, modeling clay, thermometers
Arranged around the room, you will find stations, each one having the materials to demonstrate the transformation of mechanical energy to heat energy. Try the experiment at each station, recording your results on this paper.
STATION #1: ELASTIC RANDS
1. Touch one of the elastic bands to your upper lip, sensing its temperature.
2. Remove the elastic from the vicinity of your lip, expand it rapidly, and while still stretched, once again touch it to your upper lip. Describe the sensation on your lip.
3. Was work required to stretch the elastic band?
4. Identify the energy transformations that took place.
STATION #2. HAMMER NAIL AND BLOCK OF WOOD
1. Hold a nail to sense its temperature, and then carefully pound the nail about 4 to 5 centimeters into the block of wood. Identify the work required to do this.
2. Using the claw part of the hammer, pull the nail out of the wood. Immediately touch the part of the nail that was stuck in the wood. Describe the sensation.
3. Identify the energy transformations that took place.
STATION #3. SUPERBALL
1. Very carefully place the bulb of the thermometer into the hole drilled in the. ball. Record the temperature. degrees. Remove the thermometer from the ball.
2. Bounce the ball against a hard surface for about 5 minutes. Take turns with the other members of your group.
3. After 5 minutes, insert the bulb of the thermometer into the drilled hole. Record the temperature. degrees.
4. Identify the energy transformations that took place.
STATION #4. COAT HANGER WIRE PIECES
1. Measure one milliliter of water into a small test tube. Secure the temperature of the water. degrees.
2. Bend the coat hanger wire back and forth rapidly until it breaks in the middle. Quickly place the two broken ends into the water in the test tube. Once again, record the temperature of the water. degrees.
3. Describe the work done on the piece of wire.
4. Identify the energy transformations that took place.
STATION #5: COPPER CLIP
1. Farm a base around the small copper cup using the modeling clay. Bring the clay up to the edge of the copper cup.
2. Measure out two milliliters of water into the copper cup. Record the temperature of the water. degrees.
3. Secure the nail into the chuck of the hand drill with the head of the nail sticking out.
4. Position the head of the nail against the bottom of the cup and turn the handle on the drill for 5 minutes. Do this without stopping, taking turns with the other members of your group.
5. After 5 minutes, record the temperature of the water. degrees.
6. Describe the work you did on the drill.
7. Identify the energy transformations that took place.
ENERGY SMORGASBORD
|Device |Type |
| 1. Radiometer |Demo |
| 2. Festaware and Geiger counter |Demo |
| 3. Shaking solids I – Copper/steel |Demo |
| 4. Shaking solids II - Plastic |Demo |
| 5. Shaking solids III - Sand |Demo |
| 6. Wintergreen Mint and pliers |Act |
| 7. Battery |Act |
| 8. Battery and Bulb |Act |
| 9. Battery and motor |Act |
|10. Motor and Bulb |Act |
|11. Alka Poppers |Act |
|12. Hand Generator |FYI |
|13. Radio speaker and Galvanometer |Demo |
|14. Radio speaker to radio speaker |Demo |
|15. Hammer nail and Wood |FYI |
|16. Rubber bands |Act |
|17. Balloon and Lip |Act |
|18. Superball and thermometer |Act |
|19. Coat hanger, test tube, water |Act |
|20. Talking strip |FYI |
|21. Photo cell |Demo |
|22. Matches |FYI |
|23. Picture |FYI |
|24. Piezoelectric crystal and Neon bulb |FYI |
|25. Clap on clap off |Act |
|26. Nerf Ball Cannon |Demo |
|27. Toy car |Demo |
|28. Bimetallic Strip |FYI |
|29. Thermocouple and Galvanometer |Demo |
ENERGY SMORGASBORD
IDEA: PROCESS SKILLS:
When energy is changed from one form Observing
to another. in most cases, some energy Measuring is changed to heat.
LEVEL: TEACHER NOTES DURATION: 45 min.
STUDENT BACKGROUND: Students should know the forms of energy, and that energy can be changed from one farm to another.
ADVANCE PREPARATION: Start early gathering the materials for this activity. Practically all are readily available, and things like superball might be supplied by the students. Check around for a hand drill. The high school shop teacher might be willing to loan one.
MANAGEMENT TIPS: The teacher will have to use caution in this activity because pieces of coat hanger wire have sharp ends, elastic bands might be sent flying and fingers could he mashed while hammering nails. For health reasons, the elastic band should be discarded after a student places it on his or her lips.
RESPONSES TO STATION #1
SOME QUESTIONS: The band feels warm when it is stretched.
2. Yes, a force was exerted through a distance.
3. Chemical (muscular) - kinetic - elastic potential - heat energy.
STATION #2
1. The force of the hammer times distance drive the nail into the wood.
2. The nail feels warm.
3. Chemical (muscular) - gravitational potential - kinetic - heat energy.
STATION #3:
1. The temperature should he higher.
4. Chemical (muscular) - kinetic - gravitational potential - elastic potential - heat energy.
STATION #4:
3. The force to bend it times distance it was bent.
4. Chemical (muscular) - kinetic - gravitational potential - elastic potential - heat energy
STATION #5:
5. The temperature should be higher.
6. Hand exerted a force through distance while turning the crank.
7. Chemical (muscular) - kinetic - heat energy.
POINTS TO EMPHASIZE IN
THE SUMMARY DISCUSSION: When energy is changed from one form to another, in most cases, some energy
is changed to heat.
POSSIBLE EXTENSIONS: 1. Paper clips can be bent back and forth and then placed on the lips to detect an increase in temperature, in a manner similar to the one used in station #1. (Be sure to discard the paper clip after each use, and be careful of any sharp edges.)
2. Thermometers made of a sheet of liquid crystals are available in drug stores, and can be used to illustrate the increase in temperature of the nail.
ENERGY CONVERSIONS
How can one form of energy be converted to another form of energy?
In the chart write the name of a device that converts the form of energy listed along the left of the chart to the form of energy listed along the top of the chart. For example: the conversion of light energy to mechanical occurs using a device called the Radiometer.
| |Light |Mechanical |Heat |Sound |Electrical |Chemical |
|Mechanical |
ENERGY CONVERSIONS
IDEA: PROCESS SKILLS:
Energy can be changed from one form Inferring
to another. Classifying
LEVEL: TEACHER NOTES DURATION: 15-20 min.
STUDENT BACKGROUND: Familiarity with the variety forms of energy. ADVANCE PREPARATION:
MANAGEMENT TIPS: It is not necessary to fill in every box. The purpose of this activity is to stimulate thought and discussion about energy transformation.
RESPONSES TO
SOME QUESTIONS: Light: light bulb, sound: thunder, mechanical: steam/auto engine, electrical: thermo-couple, chemical: strike a match
Light - heat solar collector, mechanical: radiometer, electrical: solar cell, chemical: photosynthesis
Sound - mechanical: microphone
Mechanical (Motion - heat friction, sound: radio speaker. electrical: generator
Electrical - heat stove, light lightning, sound: radio speaker, mechanical: electric motor, chemical: battery charger
Chemical - heat burning, light Lumastick and fire flies, mechanical: dynamite, electrical: battery
Nuclear - heat atomic bomb reaction, light atomic bomb, sound: atomic bomb, mechanical: atomic bomb, electrical: nuclear power plant
ENERGY CHAINS
An energy chain is a picture or drawing of a series of energy transformations which traces the movement of energy from its origin to a specific outcome or activity.
Where does the energy come from, needed for a monkey to move?
Energy Chain:
Sun → Photosynthesis → Banana → Monkey → Chemical Energy → Mechanical Energy (Monkey Moves)
Where does the energy come from that is needed for a fisherman to fish?
Energy Chain:
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ENERGY CHAINS
IDEA: PROCESS SKILLS:
Energy can convert from one form to another. Observing
A series of energy conversions can be called an Inferring energy chain.
LEVEL: TEACHER DURATION: 45 min.
STUDENT BACKGROUND: Students should be able to recognize a form of energy.
ADVANCE PREPARATION: In the previous section, each of the forms of energy were shown to have the ability to make something move. Although it was not specifically mentioned, the participants were also witnessing a series of energy conversions from the form under consideration to mechanical energy. In this demonstration a series of energy conversions, or "energy chains' will be demonstrated. Have the participants identify the energy forms involved as each change takes place. Each chain can be ultimately traced back to our main source of energy, the sun.
Some suggested "energy chains" am as follows:
a. Wind-up toy (starting with the sun: nuclear - radiant - heat - chemical - mechanical - sound - heat)
b. Battery operated toy (starting with the time it is turned on: chemical - electrical - mechanical - sound - heat)
c. Lumastick (chemical - light)
d. Match (after being struck chemical - heat - light)
e. Hand generator (starling with the sun: nuclear - radiant -
heat - chemical - mechanical - electrical - heat - light -
sound)
MANAGEMENT TIPS: It is often helpful to group similar devices at the same work stations to show the connections between them. For example, a rubber ball that can be bounced could be placed with a small pendulum.
RESPONSES TO
SOME QUESTIONS: The responses will depend on the devices. In many cases the energy can be traced back to the sun. For example the energy to pick up a ball can be traced to food (chemical) which can be traced back through the food chain to solar energy.
POINTS TO EMPHASIZE IN
THE SUMMARY DISCUSSION: It is important to emphasize that things do not use up" energy. but rather the energy changes form. For example. in a battery operated toy, energy transfers from being concentrated in the chemical energy of the battery. through several forms, until it ends up as heat energy scattered around the room. in its final form it is less useful because it isn't concentrated, but it is not "used up." (More derail on this idea is presented in section IV.)
WORKSHOP LEADER'S PLANNING GUIDE
THERE ARE TWO TYPES OF ENERGY
Using several activities, the participants will get some "hands on" experiences illustrating examples of potential and kinetic energy. For the upper level grades (6-8). the equations for gravitational potential energy and kinetic energy will be discussed. The only prerequisite for this subtopic is an understanding of the metric units of force, mass, and distance.
Naive Ideas:
1. An object at rest has no energy.
2. The only type of potential energy is gravitational.
3. Gravitational potential energy depends only on the height of an object.
4. Doubling the speed of a moving object doubles the kinetic energy.
A. A body may have energy by virtue of its position or condition. This type of energy is called potential or "stored up" energy.
1. Demonstration/Discussion - Focus On Physics: Potential Energy.
2. Activity: How Do Weight and Height Affect Gravitational Potential Energy?
3. Activity: Another Way of Storing Energy.
B. A body may have energy by virtue of its motion this type of energy is called kinetic energy.
1. Demonstration/Discussion - Focus On Physic's: Kinetic Energy.
2. Activity: Does Speed and Mass Affect Kinetic Energy?
3. FOCUS ON PHYSICS - POTENTIAL ENERGY
(Demonstration/Discussion)
Materials: hammer (should be lying on a desk or table) block of wood, nails, elastic band, wind-up toy, two identical magnets
Begin by saying "Energy is the ability to do work With respect to the top of the desk, can this hammer do work? Does it have the ability to make things move?" (No) Raise the hammer a short distance above the top of the desk, and ask, "How about now?" (Yes). Under the raised hammer, place a block of wood with a nail partially imbedded in it. Let the hammer drop, further driving the nail into the wood. Have the participants identify the force applied, the distance through which the force acted and the work done. Since the hammer had the ability to do work when it was raised, then it must of had energy in it when it was in this position. Energy stored in an object because of its position is called potential energy. Note too, that work had to be done in lifting the hammer, an amount of work equal to the potential energy gained by the hammer.
Hold the large elastic band in the palm of your hand. Ask "Does this elastic band have potential energy with respect to the palm of my hand?" (No). Stretch the elastic and hold it in the stretched position. Ask "Does it have potential energy now?" (Yes). "Why?" (There was a change in the condition of the long spiral molecules that make up rubber compounds as they were pulled into a stretched position. Once again. note that work had to be done to increase the potential energy of the band. The potential energy gained is equal to the work done in stretching the band). Set an unwound mechanical toy on the desk and ask the same type questions. "Does it have potential energy with respect to the top of the table?" Wind it up. "Does it have energy now?" Release it so the students can see it move. Identify the work done to increase the potential energy of the wind-up toy. "What part of the toy had its position or condition changed as the winding took place?" (The spring). This type of stored energy is called elastic potential energy.
Place a magnet on the desk and ask the same type of questions. "Does it have potential energy with respect to the top of the table?" Take another similar magnet and push it against the first one so that their like poles are held together. "Does it have energy now?" Release it so the students can see it move. Identify the work done to increase the potential energy of the magnets. The magnets gained energy because of their position. This type of stored energy is called magnetic potential energy.
1. Potential or stored energy
PE = F x h
2. Kinetic or moving energy
KE = ½m x v2
AH-LA-BOUNCE
Purpose: To discover the amount of potential energy a super ball has before and after one bounce. To calculate the amount of energy absorbed in the bounce.
Equipment: super ball, measuring tape, calculator
Procedure:
1. Stretch as high as possible and mark a spot on the wall. This will be the initial height, and the height you will drop the super ball. Record the height (h1) from the top of the ball in meters
2. Drop the ball so that you get a good (straight up) bounce.
3. Mark the maximum height of the first bounce. Record the height (h 2 ) from the top of the ball in meters.
4. Make at least three trials and average the height (h 2)
5. Find the mass of the ball, record as mass (m) in kilograms.
6. Using the constant for the acceleration due to gravity (g) as 9.8 m/sec2.
7. Calculate PE1 = m x g x h1 in the unit joules.
8. Calculate PE2 = m x g x h2 in the unit joules.
(Estimate the amount of energy absorbed. )
9. Calculate the % of energy absorbed. % of energy absorbed = ((PE1 - PE2) / PE1) x 100. The % of energy absorbed is the amount of energy that was used up in the bouncing of the ball.
DATA TABLE
Mass of super ball ______________Kg Mass of tennis ball ______________Kg
|Trials |Super Ball |Tennis Ball |
| |h1 (meters) |h2 (meters) |h1 (meters) |h2 (meters) |
|1 | | | | |
|2 | | | | |
|3 | | | | |
|average | | | | |
|Potential Energy | | | | |
|m x g x h | | | | |
|% of energy absorbed | | | | |
HOW DO WEIGHT AND HEIGHT AFFECT GRAVITATIONAL
POTENTIAL ENERGY?
Materials: Aluminum pie plate (disposable type), 2 film cans (one filled with sand), meter stick, spring scale (0-5 Newtons), 2-30 cm pieces of string
I. Gravitational potential energy and height
1. Place pie plate upside down on the floor.
2. Place the film cans (empty and full) on the pie plate. Can the pie plate support them without being dented?
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3. Remove the film can from the pie plate. Lift the empty film can to a height of .25 m above the plate. Drop the can onto the plate. Describe what it did to the pie plate.
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4. Predict what will happen if the empty can is dropped from a height of 1 m.
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5. Drop the empty can from a height of one meter. Did your predictions come true? (You may repeat the dropping from both heights several times to check your results. Flatten out any dents between drops.) Explain how the height of an object affects its potential energy.
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II. Gravitational potential energy and weight
6. Tie a string around each film can so they can be hung on the spring scale. Weigh each can.
mass of empty can _______________ mass of full can ____________________
7. Predict what will happen if each can is dropped onto a pie plate from a height of 0.5 m.
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8. Drop each can from a height of .5 in starting with the empty can. Repeat this several times, flattening out the plate each time. Explain how the weight of an object affects its gravitational potential energy.
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III. Energy In everyday life
9. Why would a sledgehammer be used to split rocks rather than a carpenter's hammer?
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10. People in the upholstery business use a small hammer called a tack hammer. Would you want to build a house with only a tack hammer for nailing? Explain.
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11.. Would be falling off of the bottom step of a ladder or the top step be more dangerous,? Explain you answer using potential energy.
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HOW DO WEIGHT AND HEIGHT AFFECT GRAVITATIONAL
POTENTIAL ENERGY?
IDEA: PROCESS SKILLS:
A body may have energy by virtue of its position or Inferring
condition. This type of energy is called potential or Observing "stored up" energy. One form of potential energy is
gravitational potential energy. The more weight or
height an object has, the more gravitational potential
energy is stored in it.
LEVEL: TEACHER DURATION: 20-25 min.
STUDENT BACKGROUND: At this point, students should know that energy is the ability to do work.
ADVANCE PREPARATION: If spring scales are at a minimum, one can be shared by all of the groups. Pennies or (almost) any heavy small objects may be used as a substitute for the sand in the film cans.
MANAGEMENT TIPS: 1. Students may want to open the filled film can to see what's inside. Caution them to do this with care and to seal it back up securely to avoid spilling the contents.
2. An alternative to using the pie plate is to drop the objects into modeling clay or play dough. Then a permanent record of the impacts can be kept
RESPONSES TO
SOME QUESTIONS: 2 Yes.
3. The pie plate is slightly dented.
5. Yes. The more height an object has the more gravitational potential energy is stored in it.
7. The empty plate will be dented more by the full can than by the empty can.
8. The more weight an object has the more gravitational potential energy is stored in it at a given height.
9. A sledgehammer is heavier than a carpenter's hammer. therefore at a given height it will have more energy.
POINTS TO EMPHASIZE IN
THE SUMMARY DISCUSSION: 1. Relate the size of the dent to the amount of work done on the pie plate. The larger the dent the more work done, and therefore the film can had more gravitational potential energy .
2. The potential energy gained by a body is equal to the work done on it (computed by multiplying), the force exerted (equal to the weight of the body) times the vertical distance it is raised (height). Gravitational potential energy, then, is simply equal to the weight of a body times the height to which it is raised.
PEgrav = weight x height = Newtons x meters = joules
POSSIBLE EXTENSIONS: Try to relate this to examples of potential energy in your geographic areas such as avalanches, hydroelectric power, water towers, putting hay in a loft, etc.
GALILEAN CANNON
A.K. Dewdney
A rubber ball bounces handily on a hard floor, but nothing bounces like a steel ball on a firmly supported steel plate. There is a strange device (see the Reading List). I call the Galilean cannon that exploits the astonishing elasticity of steel to create some equally astonishing speeds. No gunpowder is necessary for a Galilean cannon, just a few cannonballs of different sizes!
When two elastic bodies such as balls collide, there is a transfer of momentum between the bodies. For example, a moving ball may strike an identical stationary ball squarely in the center. The moving ball will instantly stop and the stationary ball will move off at the same speed of the original ball. If the moving ball is very much larger than the stationary one, it will continue on nearly unabated and the smaller ball will rocket off at twice the large balls velocity.
This, at least, is the theoretical picture. In the real world, this collision is less than 100% efficient, the stationary ball moves off at a slightly slower speed, and so on. But I will pretend, in describing the Galilean cannon, that we live in an ideal world in which inconvenient details can be ignored.
Only in the idealized laboratory of the mind are many inventions and ideas first tried out. Those of you who build the Galilean cannon will discover the truth for yourselves.
Imagine the following experiment. If a steel ball is dropped on a steel plate, the ball will rebound to the point at which it was dropped. Suppose that a large steel ball is dropped on the steel plate and that almost immediately a second, smaller ball is released directly above it. Within a millisecond of the large balls bounce, the second ball collides with it.
If the large ball had reached a velocity of v when it struck the plate, it will rebound upward with this same speed. The second ball, according to Galileo, is also traveling at the speed v when it strikes the large ball going upward (neglecting the large balls diameter for the moment).
What happens when a large ball collides head-on with a small ball, both traveling at the same speed? If the large ball is sufficiently massive, it will lose practically no speed in the collision and the small ball will rebound at a speed of 3v. Think about this for a moment.
In this simple mental experiment lies the seed of an idea for a cannon of sorts. Imagine, for example, three steel balls, one 10 centimeters (4 inches)in diameter, one 2 centimeters (0.8 inch) in diameter and one about the size of a ball bearing, say 4 millimeters (0.16 inch). The three balls are dropped as a train, each directly over its predecessor, as shown in Figure 3. There does not need to be any space between the balls. The rebounds will occur anyway.
What happens when the three-ball train hits the steel plate? The bottom ball will rebound at speed v and, as we have already seen, the second ball will rebound at speed 3v. How fast will the third ball rebound? It is time to solve the general problem.
If a heavy ball is moving upward at speed v when it strikes a light ball moving downward at speed y, imagine a frame of reference that moves upward with the larger ball. Relative to this frame, the small ball approaches at a speed of x + y. It therefore rebounds from the larger ball at a speed of x + y in the upward direction. But that is in relation to a frame of reference that is already moving upward at speed x. This speed must therefore be added to the speed of the upward rebound, x + y, resulting in the speed 2x .+ y. Now, if x is 3v and y is v, the answer to the question just posed is 7v!
As some readers may already have begun to suspect, each time we add a new ball to the train, the speed doubles, in effect. Here is a little table showing rebound velocities for trains of up to eight balls:
Number of Rebound
Balls Speed
1 1v
2 3v
3 7v
4 15v
5 31v
6 63v
7 127v
8 255v
To really appreciate the idea in more concrete terms, imagine that the eight ball train is dropped from a height of 10 meters (33 feet). This is about the roof height of a two-story house. The velocity of the train when it hits a massive steel plate or block on the ground would be slightly greater than 10 meters per second, but we will suppose just 10 meters per second for ease of calculation. On the rebound, the smallest ball whizzes upward at 2,550 meters (8,364 feet) per second. This is more than twice the speed of a high-velocity rifle bullet and more than seven times the speed of sound. Galilean cannon balls may not be large, but they are fast!
One might imagine putting a ball bearing in orbit with a Galilean cannon by adding just a few more balls. Unfortunately, air friction would intervene. And so would a lot of other factors, in any case.
Those of you with a little physics background are in an excellent position to calculate what the rebound velocities would be for actual steel balls. Taking both the coefficient of restitution of a steel ball, as well as actual masses into account will produce more modest velocity formulas (but not that modest). The effect is still very much there even when each ball in the train is twice the diameter of its successor. This brings us to actual construction.
In an experimental Galilean cannon, the "ball§' are not necessarily spherical. Solid steel rods with rounded ends might work as well. In such a case, greater lengths would have larger masses. The last two or three "balls' might be truly that, each nestled temporarily in a little pocket in its predecessor. The whole train could then be dropped down a smooth steel pipe, the barrel of the Galilean cannon.
Caution: Needless to say, anyone who builds this device with the hope of exploring its technological limits must take appropriate safety precautions when testing it. In particular, arrange to drop the balls remotely from a safe location and either use a deflector plate to contain the shots or take due care that the balls do not land where there are likely to be people!
ABOUT THE AUTHOR
A,K. Dewdney, who for eight years wrote columns about computers and mathematical recreations for Scientific American, is a professor of computer science at the University of Western Ontario, He is the rounding editor of Algorithm, a magazine devoted to recreational and educational computer programming. Professor Dewdney's interests extend far beyond the realm of computing to include amateur astronomy, paleontology, botany and biology,
ANOTHER WAY OF STORING ENERGY
Materials: empty thread spool, Q-tips, or large wooden matches, elastic bands, paper clip, scotch tape, button
1. Loop the rubber band through two of the holes in the button as shown.
2. Make a small hook in the end of a paper clip and use it to pull the rubber band through the hole in the spool, as shown below.
3. Hold the rubber band in place in the spool by inserting a short length of Q-tip or a piece of the wooden match through the ends of the band. Use small pieces of rape to hold the stick in place, as shown below.
4. Insert a Q-tip or match through the other end of the rubber band, so that one end sticks out beyond the edge of the spool, as shown below.
5. Using the long end of the stick, wind the rubber band 5 complete turns. Place it on its side on a table and let it go. Observe the result.
6. Explain what happened to the spool when it was placed on the table.
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Why did you have to wind the elastic band?
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Explain where the energy came from to drive the spool.
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Wind the spool again 5 times and using a ruler, measure how far it travels. Centimeters
9. Predict what will happen if you wind the rubber band 10 turns. Test your prediction by winding the band 10 times and letting it go on the table. Describe the result and compare it to your prediction.
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Experiment with your motorized spool by measuring the distance it travels when it is wound 10, 15, 20 turns.
10 turns centimeters
15 turns centimeters
20 turns centimeters
Does the spool go twice as far with 20 turns as it did with 10 turns? Explain why it did or did not.
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11. Wind the rubber band 10 turns and hold the stick in place with a piece of tape. Put the spool away until the next day.
12. After storing the spool oversight, remove the tape and release the spool on the table. How far does the spool go now?
Centimeters
How well did the rubber band store energy overnight?
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ANOTHER WAY OF STORING ENERGY
IDEA: PROCESS SKILLS:
A body may have energy by virtue of its position or Observing
condition. This type of energy is called potential or Inferring "stored" energy.
LEVEL: TEACHER DURATION: 30-45 min.
STUDENT BACKGROUND: Students should have discussed the meaning of potential energy. Also, work must be done to store energy in a spring or elastic band.
ADVANCE PREPARATION: Stan early rounding up spools. Ask the children to bring in spools from home. Tailor shops and fabric stores may have spools they would be willing to donate. Plastic spools can be used, however the paper ends should be kept on. The rest of the materials are readily available.
MANAGEMENT TIPS: The students enjoy assembling this rubber band motor. Caution the students not to hook themselves with the bent paper clip. Experiment with the number of turns of the stick. Too many alms result in wild and erratic motion. If there is too much friction try lubricating the surface between the button and the spool by rubbing them with an old candle.
RESPONSES TO
SOME QUESTIONS: 6. It was driven along by the elastic as it unwound.
7. To do work (store energy) by changing the tension in the band.
8. The potential energy stored in the rubber band.
10. It travels farther. More work done, more potential energy.
11. Part 2: Probably not. Energy lost as driving stick skids on the table top (friction).
14. Very well.
POINTS TO EMPHASIZE IN
THE SUMMARY DISCUSSION: Work must be done in storing energy in the elastic band. Have the students identify the force and the distance.
Doing twice as much work may not give you twice as much useful energy. The tighter the elastic band is wound, the faster the stick spins, causing a greater amount of slippage on the table.
POSSIBLE EXTENSIONS: 1. Large versions of this motor can be made with spools used by photo developing shops to hold photographic paper, and pencils instead of matches.
2. Rubber band motors in model airplanes.
FOCUS ON PHYSICS
KINETIC ENERGY
(Discussion)
When a person throws a bowling ball, work is done on the ball to get it going. Once the ball is going it has the ability to do work on another object such as the pins at the end of the lane. This "energy of motion" is called kinetic energy.
Kinetic energy is very important in everyday life. A car traveling down the mad has kinetic energy, and the more it has the harder it is to stop. Moving water was used to run mill wheels in the old days and is used today to ran hydroelectric power plants. This water has energy because it is moving — kinetic energy. It is the kinetic energy of the wind that is used to make wind generators and sailboats go. Sometimes, such as in tornados and hurricanes, the kinetic energy of the wind becomes too much and can cause great destruction.
Kinetic energy is also important on the microscopic scale. The more kinetic energy the molecules of an object have, the hotter it will be. Heat energy is related to kinetic energy. The sounds people hear are caused by the motion of their ear drum. Sound is also related to kinetic energy!
The next activity investigates the factors that affect the kinetic energy of an object.
INVESTIGATING POTENTIAL AND KINETIC ENERGY
Objectives
1. Given the following list of terms, identify each term's correct definition. Conversely, given definitions identify their correct terms. acceleration, force, kinetic energy, mass, Newton, potential energy, power, velocity,
2. Given the formula for potential energy P.E. = m x g x h, or the formula for Kinetic Energy K.E. = 1/2 m x v2, determine which formula to use and calculate the amount of energy.
3. Given the formula for work w = f x d, calculate the amount of work given force and distance.
4. Given the formula where p = power, w = work, and t = time calculate the power using the formula p = w / t.
5. Identify the affect of force on potential and kinetic energy.
6. Identify the affect of mass on potential and kinetic energy.
Materials
toy truck Newton scale
2 - .060 Kg masses mass to be pushed
string for mass stopwatch with sensors
device to change height of inclined plane .0355 Kg mass
Meter stick balance or pre-massed objects
inclined plane - ramp
Truck Set-Up
1. Set-up the equipment as indicated in the figure.
a. connect the two pieces of the ramp together.
b. connect the electronic sensor to the stopwatch
c. place one of the sensors in the t1 position and the other sensor in the t2 position. The distance is 0.400-m.
d. adjust the height of the support block to the height indicated in the table.
e. place the support block at the .380-m position.
Section 1: Does Potential And Kinetic Energy Depend On Height (Force)?
While keeping the release position constant we will vary the force (height)
1. In this experiment we will keep the release position constant while varying the height of the support block. This will change the force on the truck.
2. Determine and record the mass of the truck.
3. Set the block, as indicated in the table, and place the block under starting point of the truck. Measure and record the truck height (h) from the top of the table to the top of the ramp, at the starting point.
4. Measure the force of the truck using the Newton scale. Hook the Newton scale on the truck and hold the body of the scale in your hand parallel to the ramp so the weight of the scale does not pull on the truck.
5. Release the truck and measure the time needed to travel through the timed distance.
6. Repeat the experiment changing the support block height. Remember to measure the height and the force for each new support block height.
7. Calculate the average time, velocity, potential and kinetic energy. Formulas are provided in the chart.
8. Does the change in height (force) on the truck effect time and energy, explain?
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9. Explain why potential energy and kinetic energy are not numerically equal.
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|Position from Start: -m |Height (h): Measured | Gravity (g): 9.8 m/sec2 |
|Mass of truck (m) -Kg |Timed Distance (d): -m |Block Height: Given |
| |Time Trials |Speed |Energy |
|Experiment |
8. Explain why potential energy and kinetic energy are not the same.
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| |Height (h): Measured | Gravity (g): 9.8 m/sec2 |
| | | |
| | | |
|Position from Start: -m | | |
|Force on truck (f): Measured |Mass of truck (m): Variable |Timed Distance (d): -m |Block Height -m |
|Time Trials |Speed |Energy |
|Experiment |
8. Was energy conserved? Explain.
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|Position from Start: -m |Block Height: Given |Gravity (g): 9.8 m/sec2 |
|Force to move block (f): Measured |Mass of truck (m): -Kg |Distance (d) Block moves: Measured - chart |
| Experiment |
9. Compare the work done on the wooden barrier to the potential energy of the truck as calculated.
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| Position from Start: -m |Block Height: -m |Gravity (g): 9.8 m/sec2 |
|Force to move block (f): Measured |Mass of truck (m): Variable |Distance (d) Block moves: Measured-chart |
|Experiment |
4. Release the pendulum (don't push it!) and observe its motion for one complete swing (across and back). Where was it traveling the fastest?
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5. What kind (or kinds) of energy did it have at this point?
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6. What kind (or kinds) of energy did it have halfway between the high point and the low point of its swing?
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7. What kind (or kinds) of energy did it have when it was at the opposite end of the swing from where it was released?
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8. Summarize you answers to questions 3-7 by describing the energy transformations that occur as a pendulum swings from one side m the other and back.
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9. Pull the weight back to the height of the stung and again release the pendulum, observing its motion for one complete swing (across and back). Does it return to the same height as it started? Explain why or why not.
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10. Pull the weight back to the height of the string and again release the pendulum, this time letting it make 5 complete swings. On the last swing, did it return to the height from which you first released it? Explain why or why not using energy.
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ENERGY TRANSFORMATIONS AND THE PENDULUM
IDEA: PROCESS SKILLS:
When energy is converted from one form to Observing
another, the total amount of energy remains Inferring the same.
LEVEL: TEACHER DURATION: 30 min.
STUDENT BACKGROUND: Students should be familiar with the concepts presented in the other sections of this book.
ADVANCE PREPARATION: Cut the string to the lengths required for the desks in the room you are using.
MANAGEMENT TIPS: Almost any small object that has a weight of about 1 Newton (approx. 1/4 lb.) can be used for the pendulum weight. Lighter objects can also be used. They are however more affected by friction (mechanical energy losses due to conversion to heat energy). Be sure that students don't give the pendulum a push as they release it
RESPONSES TO
SOME QUESTIONS: 3. Gravitational potential energy.
4. At the bottom, or low point of the swing.
5. Kinetic energy.
6. Gravitational potential energy and kinetic energy.
7. Gravitational potential energy.
8. Work is done to pick the weight up to the height of the string, and this gives the weight gravitational potential energy. As the weight falls, its gravitational potential energy decreases and its kinetic energy increases. At the bottom its kinetic energy is at a maximum and its gravitational potential energy is zero. On the way up the other side, the process is reversed -- kinetic energy decreases and gravitational potential energy increases.
9. Yes (or fairly close). The total amount of energy is constant or conserved.
10. No. As the weight moves through the air. friction with the air and with the string causes some of the mechanical to be converted to heat energy.
POINTS TO EMPHASIZE IN If no energy was converted to heat energy, the total mechanical energy
THE SUMMARY DISCUSSION: (potential + kinetic) at any point in the system would be constant As the pendulum makes its first swing, very little energy is converted to heat energy and the weight returns to Dearly the same height. As it continues to swing, the small amount of mechanical energy lost to heat energy with each swing begins to add up, as shown by the weight not returning to the original height. It is important to note that the energy convened to heat energy is not destroyed or truly "lost" It merely leaves the pendulum system and goes off into the air of the room and from there is spread out around the universe. The energy leaves the pendulum, but it is not destroyed. Energy is conserved!
POSSIBLE EXTENSIONS: 1. A playground swing could also be used to-illustrate the transfer of potential energy to kinetic energy to potential energy.
2. A dramatic extension of this activity is to construct a heavy pendulum which is supported by a strong pivot point on the ceiling, such as by tying it to an "I" beam. The pendulum is adjusted so that when the weight is pulled back it comes in contact with a person's nose when he or she is standing with their head against a wall. When it is released (not pushed!) it will travel across the room and return to a point close to the person's nose but not touching it Obviously, caution must be exercised to insure that the rope used is strong and well-attached to the weight and a strong support. It should be attached in a manner that prevents slipping.
3. STOP AND GO BALLS
(Demonstration/Discussion)
Tie about 50-75 cm of swings between two supports (the backs of two chairs work fine). Suspend two tennis balls from the string using pieces of swing about 40 cm long. They should be about 20 cm apart (see diagram below).
Start one of the balls swinging. Now that the other ball begins to respond to this motion, and as its amplitude of swing starts to increase, the ball that was initially moving starts to lose some of its energy. This continues until the ball that was originally at rest is swinging with full amplitude, and the other ball comes to a complete stop. The cycle continues with the balls transferring energy from one to the other.
The energy is transferred by the process of resonance, but it is not necessary to get into a discussion of the method at this time. What should be pointed out is that energy is conserved. As one ball gives up its energy, it is gained by the other. Have the participants reason out why the swings gradually diminish (heat losses due to friction at the knots, air resistance).
COAT HANGER CANNON
EQUIPMENT: Coat Hanger Cannon: take a coat hanger and unbend it. The hanger end should be bent into a loop that can fit over a support rod. Place a sharp bend, approximately. 2 cm. at the other end to hold the projectile. Projectile: small piece of wood - approximately 2 cm. cube with a hole drilled in it, Metric ruler, Stop watch
ENERGY TRANSFORMATIONS AND THE HAND GENERATOR
Materials: 2 hand powered generators (Genecons), sets of clip leads for the generators, 1 miniature light bulb (7.5 volt) bulb holder, 2 "D" cell batteries, masking tape
1. Place the bulb in the bulb holder. Plug a set of clip leads into the generator and connect one of the clip leads to each terminal on the bulb holder. Crank the handle of the generator and observe. Describe what happens in terms of energy transformations.
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2. Tape the two batteries together in series (the positive terminal of one to the negative of the other). Hold one of the clip leads from the generator to each of the remaining terminals. Describe what happens in terms of energy transformations.
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3. Connect the two generators to each other as shown. Using what you observed in the previous two steps, predict what will happen when you turn the crank of one of the generators.
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4. Turn the crank of one of the generators. Describe what happens in terms of energy transformations.
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5. Turn the crank of the first generator ten revolutions while your partner counts how many revolutions the crank of the second generator makes. Record the results.
Number of revolutions of the first generator 10 .
Number of revolutions of the second generator
6. Did the two generators make exactly the same number of revolutions? Discuss why or why not in terms of energy transformations.
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ENERGY TRANSFORMATIONS AND THE HAND GENERATOR
IDEA: PROCESS SKILLS:
When energy is convened from one form to Inferring
another, the total amount of energy remains Observing
the same.
LEVEL: TEACHER DURATION: 30 min.
STUDENT BACKGROUND: Students should be familiar with the concepts presented in this book.
ADVANCE PREPARATION: Gather the materials. Students need to be in groups of at least two.
MANAGEMENT TIPS: A bulb with a voltage lower than 73 volts can be used in #1; however, if the generator is cranked too rapidly, the bulb will blow out If battery holders are available, then the taping together of batteries in #2 can be omitted. If tape is used, the batteries have to be taped tightly to insure good contact. Pushing them together when putting on clip-leads will also help to insure good contact. In #3 the polarity of the connections does not make a difference. Let the students try it both ways. (The direction in which the second generator turns will be reversed.)
RESPONSES TO
SOME QUESTIONS: 1. Mechanical energy is converted to electrical energy which is convened to light and heat by the bulb. Heat energy and sound are also created by the friction in the gears of the generator.
2. Chemical energy in the battery converts to electrical energy. When electrical energy is put into a generator it becomes an electric motor and converts the electrical energy into mechanical energy. As the generator turns, heat energy and sound are also created by the friction in the gears.
3. When the first generator is cranked, the second one will turn.
4. When the first generator is turned, mechanical energy is convened to electrical energy. This electrical energy goes into the second generator which converts it back to mechanical energy. In the process, heat energy and sound are also created by the friction in the gears of both of the generators.
5. Less than 10.
6. No. As the energy is convened from mechanical energy to electrical energy and back to mechanical energy, some of it was converted to heat energy and sound energy. This energy left the system and was not convened back to mechanical energy.
POINTS TO EMPHASIZE IN
THE SUMMARY DISCUSSION: When energy is convened from one form to another, the total amount of energy remains the same. If during the conversion some of the energy is converted to a form that leaves the system, the total amount remaining in the system will be reduced. For example, in the third pan of the activity the heat energy and sound energy that were created by the friction of the gears left the system and were not available to be convened back to mechanical energy. It is important to emphasize that this energy is not destroyed or truly "lost." It merely leaves the system and goes off into the air of the room and from there is spread out around the universe. The energy leaves the system, but it is not destroyed. Energy is conserved!
POSSIBLE EXTENSIONS: 1. This activity can be easily related to activity “Energy Transformations and the Pendulum”.
2. Ask students to write about the availability or "usefulness" of the heat energy that was scattered about the universe in this activity. This should open the door to an interesting discussion about why we are running out of energy if the total amount of energy in the universe is conserved.
DETERMINING YOUR HORSEPOWER?
1. Determine your horsepower by timing yourself walking up a flight of stairs.
horsepower = [pic]
power (watts) = work (joules) / time (seconds)
work (joules) = f (Newtons) x d (meters)
2. Distance is determined by measuring the height of one stair (in meters) as shown in the illustration and counting the number of stairs, you climbed, then multiply the height of one stair by the number of stairs.
distance = stair height x number of stairs
3. To determine the force that moved up the stairs take your weight, in pounds, which reflects the pull of gravity. Convert this pull (force) to Newtons. Since one pound is approximately 4.5 Newtons, multiply your weight by 4.5 Newtons/pound to calculate the force in Newtons.
force = your weight x 4.5 Newtons/pound
5. The energy used in climbing the stairs can be determined by measuring the amount of work done. (Work = Force X Distance). Note: the force is in Newtons and the distance in meters producing an answer with a label of Newton- meters. Another name for a Newton-meter is called a joule. Express your work done in joules.
Work = Force x Distance
6. Determine the power that was exerted as you walked up the flight of stairs.
Power = work / time
Note: the answer will have a label of joules / second. This is the definition of a unit of power called the watt. Express your power in watts.
7. Finally, let's see how we compare to our friend the horse by determining our horsepower.
Horsepower = [pic]
| |Force |Work |Power |Horsepower |
| | |W = f x d |Power = work / time |Hp = watts / 746 |
| |F |d |w |t |p |Hp |
|Trial |(Newton) |(meters) |(joules) |(seconds) |(watts) | |
|2 | | | | | | |
|3 | | | | | | |
|Average | | | | | | |
DETERMINING YOUR HORSEPOWER?
IDEA: PROCESS SKILLS:
Energy is the ability to do work. Measuring
LEVEL: TEACHER DURATION: 20-30 min.
STUDENT BACKGROUND: Familiarity with the metric system. ADVANCE PREPARATION:
MANAGEMENT TIPS: Participants should know their weight in pounds prior to this activity. Be sure there is no horse play on the stairs which might result in injury.
RESPONSES TO
SOME QUESTIONS: Answers to questions vary.
POINTS TO EMPHASIZE IN
THE SUMMARY DISCUSSION: 1. When you are measuring work done against gravitational forces, only the vertical distance between the two levels is needed. (This topic is covered in detail in "SIMPLE MACHINES".) The work calculated in this lab is only the work to move your body as a whole. Energy is also required for all the internal processes (circulation, respiration, etc.) that keep you alive and and for you m pick your legs up and down in the act of walking. The next activity (IB4) is an excellent follow-up to this activity.
2. How does the amount of work done against gravity when someone walks up the stairs compare to the work done against gravity when someone runs up the stairs? (The sane).
POSSIBLE EXTENSIONS: 1. Although the concept of power is covered in the workshop "SIMPLE MACHINES" the students in the upper grades might be interested in calculating the rate at which their legs can do work (or expend energy). This rate is called power to do this, time the students as they run up the stairs..
Power = Work = Newton-Meters = Joules = Watts
Time Sec. Sec.
The unit of power is the watt. (Note: every 746 watts = 1 horsepower) Student power values often come out high because they usually only run up one flight of stairs. The values would lower drastically if they had to run up stairs for a whole day!
HOT ROD POWER
Determining the horsepower needed to lift an object
[pic]
1. Determine the horsepower of a small battery powered car as it lifts a load (force) through a timed distance. Set-up the equipment on the table top as indicated in the above figure. If the wheels spin you will need to wash them with soapy water and possibly even the tabletop to get the best traction. To calculate Horsepower you will need to determine force, work, and power.
Horsepower =
power (watts) = work (joules) / time (seconds)
work (joules) = f (newtons) x d (meters)
2. To determine force, obtain the mass (in Kilograms) of the object to be lifted by the battery powered car. Convert the mass to Newtons by multiplying by 9.8 m/sec2. (You may wish to try other masses, but you will need a mass that the car can pull.)
Force (Newtons) = mass in Kg x 9.8 m/sec2
3. To determine work identify and measure, on the track, the distance, in meters (approximately 0.50-m), that your car pulls the load and multiply it times the force of the load being lifted.
work (in joules) w = f x d
4. To determine power obtain the work and then divide it by the average time needed to lift the load.
power (watts) p = w / t
5. To determine the horsepower divide the power, in watts, by the number of watts in a horsepower (746).
Horsepower =
| |Force |Work |Power |Horsepower |
| |F = m x g |W = f x d |Power - work / time |Hp= watts/746 |
| |m. |g |F |d |W |t |
|Trial |(Kg.) |(m/s2) |(Newton) |(meters) |(joules) |(seconds) |
|Mechanical | | | | | | |
|Electrical | | | | | | |
|Chemical | | | | | | |
|Thermal | | | | | | |
|Sound | | | | | | |
|Light | | | | | | |
Energy Conversion Dominoes: Cut out the 24 energy conversion dominoes on the handout. (For extra durability they can be mounted on card stock beforehand.) Place them face down on a table. Distribute 12 of the dominoes equally among the players. That is, two players will each draw six dominoes, three players will each draw four, four players will each draw three, and five or six players will each draw two. (The game is not suitable for a larger number of players.)
In “regular” dominoes, the highest “double” is played first. The energy conversion dominoes corresponding to “doubles” are those that convert a form of energy to the same form—for example, the refinery (converting one form of chemical fuel to another chemical fuel), the transformer (converting electric energy to another form of electric energy), and the drive shaft (converting one form of motion to another form of motion). Whoever has the double beginning with the earliest letter of the alphabet (in the order “chemical,” “electrical,” and “motion”) plays it first, and play continues counterclockwise from that point. Succeeding players complete their turn as follows: if they have a domino in their hand that can connect to exposed ends of dominoes on the board (e.g., the internal combustion engine, which uses chemical fuel, connected to the chemical fuel output of the refinery), they may play one domino from their hand per turn. If they cannot properly play a domino from their hand, they must draw from the still overturned dominoes (historically called the “graveyard”) until they draw a domino that can be properly played. The first player to play all of his/her dominoes wins.
Note that proper play of the energy conversion dominoes requires not only matching the same forms of energy but matching them in the same direction. That is, the energy output from one domino must match the energy input to the domino adjacent to it. (This is not a requirement of regular dominoes!) An actual device corresponding to the sequences of dominoes, which is characterized by a sequence of energy conversions, is known as a “Rube Goldberg” device. You may have seen devices like this on sale at gift shops, particularly at airports.
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|electricity |light |
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|electricity |motion |
|electricity |heat |
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|electricity | |
| |sound |
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|chem fuel |electricity |
|motion |motion |
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|waste heat | |
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|sound |electricity |
|waste heat |sound |
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|light | |
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|light |nuclear fuel |
|electricity |steam |
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|motion |light |
|electricity |chem fuel |
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|heat |electricity |
|electricity |heat |
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|motion |light |
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|motion motion|chem fuel |
| |heat |
|motion | |
| |sound |
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|motion |electricity |
|sound |chem fuel |
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|electricity |heat |
|light |light |
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|waste heat | |
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|sound | |
|motion |chem fuel |
| |electricity |
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|steam |chem fuel |
|motion |steam |
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|waste heat | |
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| |chem fuel |
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|sound |chem fuel |
|electricity |chem fuel |
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| |chem fuel |
ENERGY CONVERSIONS - Completed
How can one form of energy be converted to another form of energy?
In the chart write the name of an device that converts the form of energy listed along the left of the chart to the form of energy listed along the top of the chart. For example: the conversion of light energy to mechanical occurs using a device called the Radiometer.
| |Light |Mechanical |Heat |Sound |Electrical |Chemical |
|Mechanical |
Physical Science Materials Vendor List
Operation Physics Supplier
Arbor Scientific
P.O. Box 2750
Ann Arbor, Michigan
48106-2750
1-800-367-6695
Astronomy
Learning Technologies, Inc.
Project STAR
59 Walden Street
Cambridge, MA 02140
1-800-537-8703
The best diffraction grating I've found
Chemistry
Flinn Scientific Inc.
P.O. Box 219
Batavia, IL 60510
1-708-879-6900
Discount Science Supply (Compass)
28475 Greenfield Road
Southfield, Michigan 48076
Phone: 1-800-938-4459
Fax: 1-888-258-0220
Educational Toys
Oriental Trading Company, Inc.
P.O. Box 3407
Omaha, NE 68103
1-800-228-2269
Laser glasses
KIPP Brothers, Inc.
240-242 So. Meridian St.
P.O. Box 157
Indianapolis, Indiana 46206
1-800-832-5477
Rainbow Symphony, Inc.
6860 Canby Ave. #120
Reseda, California 91335
1-818-708-8400
Holographic stuff
Rhode Island Novelty
19 Industrial Lane
Johnston, RI 02919
1-800-528-5599
U.S. Toy Company, Inc.
1227 East 119th
Grandview, MO 64030
1-800-255-6124
Electronic Kits
Chaney Electronics, Inc.
P.O. Box 4116
Scottsdale, AZ 85261
1-800-227-7312
Electronic Kits
Mouser Electronics
958 N. Main
Mansfield, TX 76063-487
1-800-346-6873
All Electronics Corp.
905 S. Vermont Av.
Los Angeles, CA 90006
1-800-826-5432
Radio Shack
See Local Stores
Lasers
Metrologic
Coles Road at Route 42
Blackwood, NJ 08012
1-609-228-6673
laser pointers
Magnets
The Magnet Source, Inc.
607 South Gilbert
Castle Rock, CO. 80104
1-888-293-9190
Dowling Magnets
P.O. Box 1829/21600 Eighth Street
Sonoma CA 95476
1-800-624-6381
Science Stuff - General
Edmund Scientific
101 E. Gloucester Pike
Barrington, NJ 08007-1380
1-609-573-6270
Materials for making telescopes
Marlin P. Jones & Associates, Inc
P.O. Box 12685
Lake Park, Fl 33403-0685
1-800-652-6733
Natural Wonders
Nature Store
Flea Markets
Garage Sales
-----------------------
The MAPs Team
Meaningful Applications Of Physical Sciences
Dr. Michael H. Suckley
Mr. Paul A. Klozik
Materials in this manual are based upon the Operation Physics program funded in part by the National Science Foundation. All material in this book not specifically identified as being reprinted from another source is protected by copyright. Permission, in writing, must be obtained from the publisher before any part of this work may be reproduced in any form or by any means.
Participants registered for this workshop have permission to copy limited portions of these materials for their own personal classroom use.
Aluminum Foil Covered Cardboard
25 ml. Water
Pin
.380-m
Finish – t2
Start - t1
|Variables |Small Truck |
| Truck Height (h) |Measure & Record |
|Force on truck (f): |Measure & Record |
|Mass of truck (m): |Measure & Record |
|Timed Distance (d): |0.40-m |
|Position from Start: |0.38-m |
|Independent Variable | |
| Block Height: 1 |0.03-m |
| Block Height: 2 |0.06-m |
| Block Height: 3 |0.09-m |
|Variables |Truck |
|Truck Height (h): |Measure & Record |
|Force on truck (f): |Measure & Record |
|Position from Start: |0.38-m |
|Timed Distance (d): |0.40-m |
|Block Height: |0.03-m |
|Independent Variable | |
| Mass of truck (m): 1 |Truck |
| Mass of truck (m): 2 |Truck + 0.060-Kg |
| Mass of truck (m): 3 |Truck + 0.120-Kg |
| Mass of truck (m): 4 |Truck + 0.180-Kg |
Finish – t2
Start - t1
|Variables |Truck |
|Force to Move Block (f): |Measure & Record |
|Mass of truck (m): |Measure & Record |
|Distance Barrier Moved (d): |Measure & Record |
|Position from Start: |0.38-m |
|Independent Variable | |
|Block Height: 1 |0.03-m |
|Block Height: 2 |0.06-m |
|Block Height: 3 |0.09-m |
|Variables |Small Truck |
|Force to Move Block (f): |Measure & Record |
|Distance Barrier Moved (d): |Measure & Record |
|Position from Start: |0.38-m |
|Block Height: |0.03-m |
|Independent Variable | |
|Mass of truck (m): 1 |Truck |
|Mass of truck (m): 2 |Truck + 0.060-Kg |
|Mass of truck (m): 3 |Truck + 0.120-Kg |
rubbing objects
transformer
motor
internal combustion engine
speaker
absorber
nuclear reactor
photocell
plant
generator
toaster
thermocouple
electricity
fire
drive shaft
battery charger
tuning fork
glowing object
light bulb
battery
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ear drum
boiler
steam turbine
refinery
microphone
One Distance Unit
Two Distance Units
Three Distance Units
Object Strength = 1 Strength = 1/4 Strength = 1/9
Table
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