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Lesson 2 | Energy Transformations
Student Labs and Activities
Page
Launch Lab
27
Content Vocabulary
28
Lesson Outline
29
MiniLab
31
Content Practice A
32
Content Practice B
33
Language Arts Support
34
Math Skills
36
School to Home
37
Key Concept Builders
38
Enrichment
42
Challenge
43
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
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Energy and Energy Transformations
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Name
Date
Launch Lab
Class
LESSON 2: 15 minutes
Is energy lost when it changes form?
Energy can have different forms. What happens when energy changes from one form to
another?
Procedure
1. Read and complete a lab safety
form.
2. Three students should sit in a circle.
One student has 30 buttons, one has
30 pennies, and one has 30 paper
clips.
3. Each student should exchange 10 items
with the student to the right and
10 items with the student to the left.
4. Repeat step 3. Record your observations
in the Data and Observations section
below.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Data and Observations
Think About This
1. If the buttons, the pennies, and the paper clips represent different forms of energy,
what represents changes from one form of energy to another?
2.
Key Concept If each button, penny, and paper clip represents one unit of energy,
does the total amount of energy increase, decrease, or stay the same? Explain your
answer.
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Name
Date
Class
Content Vocabulary
LESSON 2
Energy Transformations
Directions: Define each term below. Then answer each question or respond to each statement on the lines
provided. Use complete sentences.
1. friction
2. law of conservation of energy
3. radiant
4. How does thermal energy result from friction?
6. Which example requires the use of radiant energy—starting a microwave or riding a
bicycle? Explain.
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Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
5. Give an example to explain the law of conservation of energy.
Energy and Energy Transformations
4/3/10 15:18:01
Name
Date
Class
Lesson Outline
LESSON 2
Energy Transformations
A. Changes Between Forms of Energy
1. A microwave oven changes electrical energy to
energy.
2. The changes from electrical energy to radiant energy to thermal energy are called
energy
.
B. Changes Between Kinetic and Potential Energy
1. When you throw a ball upward, the ball has its greatest speed and the most
energy when it first leaves your hand.
2. As the ball reaches its highest point, the ball gains its greatest
energy.
3. As the ball moves downward,
energy decreases and
energy increases.
C. The Law of Conservation of Energy
1. According to the
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
, energy can be transformed from one
form into another or transferred from one region to another, but energy cannot be
created or destroyed.
2.
is a force that resists the sliding of one surface over
another.
a. There is always some
between any surfaces that are
in contact with each other.
b. As you pedal a bicycle, you do
and transfer
to the bicycle.
c. Because of
between moving parts of a bicycle, some
of the work you do changes to
d. One way to reduce friction is to apply a(n)
energy.
to
surfaces that rub against each other.
e. When you apply brakes on a bicycle, the bicycle’s
energy is not destroyed; instead, the bicycle’s
is transformed into thermal energy. The
energy remains the same.
Energy and Energy Transformations
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energy
amount of
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Class
Lesson Outline continued
D. Using Energy
1. You use
energy for cooking and heating.
2. Gas stoves and furnaces change
energy from natural gas
into thermal energy.
3. During photosynthesis, plants transform
energy from
the Sun into chemical energy stored in food.
4. Your body changes the chemical energy stored in food into
energy as you move and into
energy, which keeps your body temperature high.
5. A television transforms
energy into sound energy and
energy.
6. Many devices you use every day are powered by
energy
from electrical power plants.
7. With battery-powered devices,
energy is transformed
into electrical energy for power.
8. When energy changes form, some
energy is always
released. Scientists often refer to this energy that cannot be used
.
9. Cars transform most of the chemical energy in gasoline into
energy.
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Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
as
Energy and Energy Transformations
4/3/10 15:18:03
Name
Date
MiniLab
Class
LESSON 2: 20 minutes
How does energy change form?
When an object falls, energy changes form. How can you compare energies for falling objects?
Procedure
1. Read and complete a lab safety form.
2. Place a piece of clay about 10 cm wide
and 3 cm thick on a small paper plate.
3. Drop a marble onto the clay from a
height of about 20 cm, and measure
the depth of the depression caused by
the marble. Record the measurement
in the Data and Observations section
below.
4. Repeat step 3 with a heavier marble.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Data and Observations
Analyze and Conclude
1. Infer Which marble had more kinetic energy just before it hit the clay? Explain your
answer.
2.
Key Concept For which marble was the potential energy greater just before the
marble fell? Explain your answer using the law of conservation of energy.
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4/3/10 15:18:05
Name
Date
Class
Content Practice A
LESSON 2
Energy Transformations
Directions: On each line, write the term from the word bank that correctly completes each sentence. Some terms
may be used more than once.
electrical
energy transformation
friction
kinetic
law of conservation of energy
potential
radiant
thermal
1. According to the
, energy cannot be created or destroyed.
2. A change from electrical energy to radiant energy to thermal energy is called
a(n)
.
3. A force that resists the sliding of one surface over another
is
.
4. A microwave oven changes
energy to radiant energy to
energy.
5. Suppose you are shooting a basketball toward a hoop. As the ball rises in the air, its
decreases.
6. As the ball falls back toward the floor, its
and its
energy increases
decreases.
7. Friction transforms some mechanical energy into
8. You use a lamp to change
energy.
energy into
energy.
9. When you use a battery, you transform chemical energy stored in the battery to
energy.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
energy increases and its
10. The exhaust from a car contains
energy that cannot be
used. Scientists often refer to this energy that cannot be used as waste energy.
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Energy and Energy Transformations
4/3/10 15:18:10
Name
Content Practice B
Date
Class
LESSON 2
Energy Transformations
Directions: Respond to each statement on the lines provided.
1. Write a definition of energy transformation.
2. Describe the energy transformations that occur when you toss a ball upward and it falls.
Include the causes of the transformations.
3. Compare the forms and amounts of energy before and after you apply the brakes of a
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
bicycle and stop.
4. Define friction.
5. Give an example of how mechanical energy can be transformed into another type
of energy.
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Date
Class
Language Arts Support
LESSON 2
Writing Activity: Organizing Information in Tables
Learning the Skill
Tables are organizational tools that can be used to categorize, organize, and compare
information. Tables are made up of vertical columns and horizontal rows. Table 1 below, for
example, has three columns and five rows. A table’s title summarizes the content that the
table presents.
Table 1. Examples of Different Types of Energy Transformations
Initial Form of
Energy
Final Form of Energy
Example of the Energy Transformation
chemical
thermal
gas stove
chemical
kinetic
human body breaking down food
radiant
chemical
photosynthesis
electrical
radiant
lightbulb
Directions: Use the table below to answer the questions that follow.
Factors Involved
Example of How or Where This Type of
Potential Energy Is Stored
gravitational
an object’s weight and
height
a bag lifted off of the floor
elastic
extent of stretching or
compressing
a stretched rubber band
chemical
chemical bonds
firewood
1. How many rows and columns make up the chart above?
2. Write a title for this table.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Potential Energy
3. Which type of potential energy is stored in a stretched rubber band?
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Energy and Energy Transformations
4/3/10 15:15:08
Name
Date
Class
Language Arts Support
LESSON 2
Applying the Skill
Directions: Read Table 1 in Lesson 1 of your textbook. Then use what you have learned about creating tables
to reorganize the information into the table below. Include a new title for your table.
Title:
Type of Energy
Definition
Example
mechanical energy
the energy sound carries
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
a warm oven
the energy carried by an
electric current
sunlight
nuclear energy
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Name
Date
Math Skills
Class
LESSON 2
Solve a One-Step Equation
Electricity can be measured in kilowatt-hours (kWh). One kilowatt-hour is equal to the use
of 1 kilowatt of energy for 1 hour. A kilowatt (kW) is 1,000 watts (W). To calculate the
amount of energy in kilowatt-hours, multiply the number of watts times the hours used
and then divide by 1,000.
×h
______
kWh = W
1,000
If a household uses 4,500 W each hour for 12 hours, how many kilowatt-hours are used?
Step 1 Multiply the watts times the number of hours.
4,500 × 12 = 54,000
Step 2 Divide by 1,000.
54,000
_______
= 54 kWh
1,000
Practice
1. If a household uses 1,800 W each hour
for 15 hours, how many kilowatt-hours
are used?
for 8 hours, how many kilowatt-hours
are used?
3. An electric company charges customers
for the number of kilowatt-hours used.
A household uses 2,400 W for 300 hours.
How many kilowatt-hours will be on
their electric bill?
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310 hours. How many kilowatt-hours
will be on their electric bill?
5. A household uses a daily average of
1,100 W each hour for 12 hours. What
is the average daily energy use in
kilowatt-hours?
6. A household uses a daily average of
1,400 W each hour for 10 hours. What
is the average daily energy use in
kilowatt-hours?
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
2. If a household uses 3,200 W each hour
4. A household uses 1,400 W for
Energy and Energy Transformations
4/3/10 15:37:58
Name
School to Home
Date
Class
LESSON 2
Energy Transformations
Did you know?
The law of conservation of energy was developed by German doctor Julius Robert
Mayer. Because he was a doctor and not a physicist, his law did not get the attention
of people in the scientific community. Later, other scientists wrote about the law of
conservation of energy and received credit for articulating it.
Directions: Use your textbook to complete the activity.
In this activity, you will design an investigation that demonstrates energy transformation.
1. Write a Question Think about how energy changes from one form to another. Is there
something you would like to learn about it? Write a question based on what you want
to know. It will be the basis of your investigation.
2. Form a Hypothesis Based on what you know about energy transformations, what do
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
you think the answer to your investigation question will be? This is your hypothesis.
Write your hypothesis below.
3. Develop a Method Determine the best method to check your hypothesis. How would
you get information to determine whether your hypothesis is correct? Write your method
below.
4. Collect Data How will you measure your results or collect and record your data?
Describe your data collection plan below.
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Name
Date
Class
Key Concept Builder
LESSON 2
Energy Transformations
Key Concept What is the law of conservation of energy?
Directions: On each line, write the term from the word bank that correctly completes each energy transformation.
Some terms may be used more than once.
electrical energy
radiant energy
sound energy
thermal energy
1. making toast in a toaster
changes to
.
2. watching television
changes to
and
.
3. using a curling iron to curl hair
changes to
.
4. turning on a lamp
and
.
Directions: Respond to each statement on the lines provided.
5. Describe another example of energy changing form that does not include electrical
energy.
6. What are two statements you can make about energy based on the law of conservation
of energy?
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changes to
Energy and Energy Transformations
4/3/10 15:31:55
Name
Date
Class
Key Concept Builder
LESSON 2
Energy Transformations
Key Concept What is the law of conservation of energy?
Directions: In the diagram, a ball has just been thrown and is about to be caught. Use the diagram to answer
each question. Write the letter of the correct stage on the lines provided. Some stages may be used more than once.
At the ball’s highest point its
kinetic energy is zero and its
potential energy is maximum.
KEPE
C.
Total
energy
Kinetic energy is
decreasing, and potential
energy is increasing.
KEPE
D.
Total
energy
Kinetic energy is
decreasing, and potential
energy is increasing.
B.
KEPE
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Kinetic energy is
maximum, and potential
energy is minimum.
A.
KEPE
Total
energy
Total
energy
E.
Kinetic energy is
maximum, and
potential energy
is minimum.
KEPE
Total
energy
1. At which stages is kinetic energy at the maximum value?
and
2. At which stage is the kinetic energy zero?
3. Which stage has increasing kinetic energy and decreasing potential energy?
4. At which stage is the potential energy at the maximum value?
5. At which stages is potential energy at its minimum?
and
6. Which stage has decreasing kinetic energy and increasing potential energy?
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Name
Date
Class
Key Concept Builder
LESSON 2
Energy Transformations
Key Concept How does friction affect energy transformations?
Directions: Answer each question or respond to each statement on the lines provided.
1. What happens to a bicycle’s mechanical energy when you apply the brakes and stop?
2. Compare a bicycle’s total energy when the rider is coasting, applying brakes, and
stopped.
3. Which force resists the sliding of two surfaces that are touching?
5. How can friction between a bicycle’s parts be reduced?
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Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
4. When you ride a bicycle, when is friction helpful and when is it not helpful? Explain.
Energy and Energy Transformations
4/3/10 15:32:08
Name
Date
Key Concept Builder
Class
LESSON 2
Energy Transformations
Key Concept How are different types of energy used?
Directions: Respond to each item on the lines provided. Use complete sentences.
1. Give an example of how you might use each form of energy. Include any changes that
occur from one form to another.
a. thermal energy
b. chemical energy
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
c. radiant energy
d. electrical energy
2. Explain how waste energy is produced when an inefficient lightbulb converts electrical
energy into radiant energy.
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Enrichment
Class
LESSON 2
Harnessing Solar Energy
Earth receives a tremendous amount of
energy from the Sun. Solar energy is free,
its supply is unlimited, and it produces no
air, water, or soil pollution in its natural
form. Therefore solar energy has been the
focus of research on efficient ways of
transforming radiant energy into electricity,
fuel, and heat.
Thermal and Electrical Energy
Power Plants
Solar thermal power plants use the Sun’s
rays to heat a fluid, which then enters a
heat-transfer system to produce steam. A
turbine transforms the steam into
mechanical energy, and a conventional
generator attached to the turbine transforms
the mechanical energy to electricity.
The most common type of solar power
plant is one that collects the Sun’s rays
using parabolic troughs. Curved troughs
reflect direct solar radiation onto a receiver
that runs along the trough. The receiver
(also called an absorber or collector) has a
heat-transfer fluid passing through it. The
fluid becomes hot as it passes through, and
it is then transported to a heat engine
where about a third of it is transformed to
electricity.
Applying Critical-Thinking Skills
Directions: Answer each question or respond to each statement.
1. Compare the characteristics of solar energy with those of energy from fossil fuels
with regard to effects on the environment, availability, and restriction by geopolitical
boundaries.
2. Describe In addition to the parabolic trough, two other designs for solar power plants
are (1) power towers, which use an array of movable mirrors to focus the Sun’s rays
upon a collector tower (the receiver), and (2) the dish design, in which a parabolic solar
dish focuses all the sunlight that strikes it up to a single point above the dish, where a
receiver captures the heat. How are the designs are different? How they are alike?
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Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Solar thermal energy is used to heat water
for homes, buildings, and swimming pools
and to heat spaces inside buildings. Passive
solar space-heating systems circulate air past
a solar heat surface and then through the
building by convection. Active heating
systems use a collector to absorb and collect
solar radiation. Fans or pumps then circulate
the heated air or heat-absorbing fluid.
Solar energy can be transformed to
electricity using photovoltaic devices (solar
cells) or solar power plants. Photovoltaic
cells transform sunlight directly into
electricity. When light energy strikes the
cell, it knocks electrons loose from the
atoms in the solar cell material. Electrical
conductors attached to the positive and
negative sides of the cell form an electrical
circuit, and the loose electrons are captured
as electric current.
Energy and Energy Transformations
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Name
Date
Challenge
Class
LESSON 2
Energy and Civilization
Part of the progress of humans from the time of early societies to the present has been
due to our ability to develop methods of energy transformation that furthered our survival
and the advancement of civilizations.
Trace Energy Flow
1. Describe applications of six forms of energy that you use every day.
2. For each form of energy that you described, trace a path back from its present form to
its original source on a six-part diagram or graphic organizer. Describe and label each
point of transformation along the way.
3. Distinguish the transformations that occur as part of the natural world from the
transformations that result from technological advances.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
4. Highlight the original source of each of the six forms of energy.
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