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Chapter Introduction
Lesson 1 Forms of
Energy
Lesson 2 Energy
Transformations
Lesson 3 Energy
Resources
Chapter Wrap-Up
What is energy and
what are energy
resources?
What do you think?
Before you begin, decide if you agree or
disagree with each of these statements.
As you view this presentation, see if you
change your mind about any of the
statements.
Do you agree or disagree?
1. A fast-moving baseball has more
kinetic energy than a slow-moving
baseball.
2. A book sitting on a shelf has no energy.
Do you agree or disagree?
3. Energy can change from one form to
another.
4. If you toss a baton straight up, total
energy decreases as the baton rises.
Do you agree or disagree?
5. Nuclear power plants release many
dangerous pollutants into the air as
they transform nuclear energy into
electric energy.
6. Thermal energy from within Earth can
be transformed into electric energy at a
power plant.
Forms of Energy
• What is energy?
• What are potential and kinetic energy?
• How is energy related to work?
• What are different forms of energy?
Forms of Energy
•
•
•
•
•
energy
kinetic energy
potential energy
work
mechanical
energy
•
•
•
•
•
sound energy
thermal energy
electric energy
radiant energy
nuclear energy
What is energy?
• Energy is the ability to cause change.
• Energy can cause changes in the
motions of objects.
energy
from Greek energeia, means
“activity”
What is energy? (cont.)
What is energy?
Kinetic Energy—Energy of Motion
• Kinetic energy is energy due to motion.
• All moving objects have kinetic energy.
• The faster an object moves, the more
kinetic energy it has.
• If two objects move at the same speed,
the object with more mass has more
kinetic energy.
The kinetic energy (KE) of an object
depends on its speed and its mass. The
vertical bars show the kinetic energy of
each vehicle.
Kinetic Energy—Energy of Motion
(cont.)
What is kinetic energy?
Potential Energy—Stored Energy
• Potential energy is stored energy due
to the interactions between objects or
particles.
• The gravitational potential energy stored
between an object and Earth depends on
the object’s weight and height.
• Elastic potential energy is energy stored
in objects that are compressed or
stretched.
Chemical potential energy is energy stored
in the chemical bonds between atoms.
Potential Energy—Stored Energy (cont.)
In what way are all forms of
potential energy the same?
Energy and Work
• Work is the transfer of energy that
occurs when a force is applied over a
distance.
• Work depends on both force and
distance.
• You only do work on an object if that
object moves.
The girl does work on the box as she lifts it.
The work she does transfers energy to the
box. The colored bars show the work that
the girl does (W) and the box’s potential
energy (PE).
Energy and Work (cont.)
How is energy related to work?
All energy can be measured in joules (J).
Other Forms of Energy
Describe three forms of energy.
• Energy is the
ability to cause
change.
• The gravitational
potential energy between an object
and Earth increases when you lift the
object.
• You do work on an object when you
apply a force to that object over a
distance.
Which type of energy is described
as the total energy of an object or
group of objects due to largescale motions and interactions?
A. electric energy
B. mechanical energy
C. radiant energy
D. thermal energy
What is the transfer of energy that
occurs when a force is applied
over a distance?
A. kinetic energy
B. work
C. potential energy
D. electric energy
Which term refers to energy due
to motion?
A. kinetic energy
B. potential energy
C. sound energy
D. stored energy
Do you agree or disagree?
1. A fast-moving baseball has more
kinetic energy than a slow-moving
baseball.
2. A book sitting on a shelf has no
energy.
Energy Transformations
• What is the law of conservation of
energy?
• How does friction affect energy
transformations?
• How are different types of energy
used?
Energy Transformations
• law of conservation of energy
• friction
Changes Between Forms of Energy
The changes from one type of energy to
another type of energy are called energy
transformations.
A microwave oven changes electric energy
into radiant energy.
Changes Between Forms of Energy
(cont.)
radiant
Science Use transmitted by
electromagnetic waves
Common Use bright and shining;
glowing
Changes Between Kinetic
and Potential Energy
Energy changes between
kinetic energy (KE) and
potential energy (PE)
when a ball is thrown and
moves upward and then
downward.
• As the ball moves upward,
its speed and kinetic
energy decrease, but the
potential energy is
increasing because the
ball’s height is increasing.
• At the ball’s highest point,
the gravitational potential
energy is greatest, and the
ball’s kinetic energy is the
least.
• As the ball moves
downward, potential
energy decreases. At the
same time, the ball’s
kinetic energy increases.
• When the ball reaches the
player’s hand again, its
kinetic energy is at the
maximum value again.
The Law of Conservation of Energy
According to the law of conservation of
energy, energy can be transformed from
one form into another or transferred from
one region to another, but energy cannot
be created or destroyed.
What is the law of conservation
of energy?
The Law of Conservation of Energy
(cont.)
Friction is a force that resists the
sliding of two surfaces that are touching.
friction
from Latin fricare, means “to rub”
Friction and the Law of
Conservation of Energy
• What happens to mechanical energy
when you apply the bicycle brakes and
the bicycle stops?
• A moving bicycle has mechanical
energy. When you apply the brakes, the
bicycle’s mechanical energy is not
destroyed.
Friction and the Law of
Conservation of Energy (cont.)
• The mechanical energy is transformed
into thermal energy. Friction between the
brake pad and the moving wheel
transforms mechanical energy into
thermal energy.
• There is always friction between any two
surfaces that are rubbing against each
other.
Using Energy
• When you use energy, you usually
change it from one form into another.
• All forms of energy can be transformed
into thermal energy.
• During photosynthesis, a plant
transforms the Sun’s radiant energy into
chemical energy that it stores in
chemical compounds.
Using Energy (cont.)
What happens to energy when
it is used?
Using Energy (cont.)
• When energy changes form, some
thermal energy is always released.
• Scientists often refer to thermal energy
that cannot be used as waste energy.
• Whenever energy is used, some energy
is transformed into useful energy and
some is transformed into waste energy.
• Energy can change
form, but according
to the law of
conservation of
energy, energy can
never be created or
destroyed.
• Friction transforms mechanical
energy into thermal energy.
• Different forms of energy, such as
sound and radiant energy, are used
when someone talks on a cell phone.
All forms of energy can be
transformed into what form
of energy?
A. electric energy
B. radiant energy
C. thermal energy
D. sound energy
What term refers to the changes
from one type of energy to
another type of energy?
A. law of conservation of energy
B. friction
C. potential energy
D. energy transformations
During photosynthesis, a plant
transforms the Sun’s radiant
energy into what type of energy?
A. chemical energy
B. electric energy
C. kinetic energy
D. thermal energy
Do you agree or disagree?
3. Energy can change from one form to
another.
4. If you toss a baton straight up, total
energy decreases as the baton rises.
Energy Resources
• What are nonrenewable energy
resources?
• What are renewable energy
resources?
• Why is it important to conserve
energy?
Energy Resources
• nonrenewable energy resource
• fossil fuel
• renewable energy resource
• inexhaustible energy resource
Sources of Energy
• Almost all the energy you use can be
traced back to the Sun.
• A small amount of energy that reaches
Earth’s surface comes from inside Earth.
Electric Power Plants
• Most of the electric energy you use
comes from electric power plants, which
transform the energy in an energy
source into electric energy.
• One source of energy comes from
burning fuels, such as coal.
• Nuclear power plants use the nuclear
energy in uranium and hydroelectric
power plants convert the kinetic energy
in falling water into electric energy.
This coal-burning electric power plant
transforms chemical energy stored in a
fossil fuel into electric energy.
Nonrenewable Energy Resources
• A nonrenewable energy resource is
an energy resource that is available in
limited amounts or that is used faster
than it is replaced in nature.
• Fossil fuels are the remains of ancient
organisms that can be burned as an
energy source.
Nonrenewable Energy Resources
(cont.)
fossil
from Latin fossilis, means
“dug up”
Nonrenewable Energy Resources
(cont.)
Why are fossil fuels considered a
nonrenewable energy resource?
Nonrenewable Energy Resources
(cont.)
• Petroleum and natural gas
formed from microscopic ocean
organisms that died and sank to the
ocean floor.
• The chemical potential energy stored in
fossil fuels changes to thermal energy
when fossil fuels burn.
• Petroleum, coal, and natural gas are all
examples of fossil fuels.
Formation of Petroleum
Geologic processes buried these dead
organisms under layers of sediment and
rock. High temperature and pressure
changed them into oil and natural gas.
Nonrenewable Energy Resources
(cont.)
• Over the past 100 years,
Earth’s surface has warmed by about
0.7°C, which is due, in part, to the
increasing amount of carbon dioxide
produced by burning fossil fuels.
• In nuclear power plants, breaking apart
uranium nuclei transforms nuclear
energy into thermal energy.
A nuclear power plant transforms nuclear
energy into electric energy.
Renewable Energy Resources
A renewable energy resource is an
energy resource that is replaced as fast
as, or faster than, it is used.
Contrast renewable and
nonrenewable energy resources.
Renewable Energy Resources (cont.)
• The most widely used renewable energy
resource is falling water.
• A hydroelectric power plant transforms
the kinetic energy in falling water into
electric energy.
A hydroelectric power plant converts the
potential energy of the water stored behind
the dam to electric energy.
Renewable Energy Resources (cont.)
• An inexhaustible energy resource is
an energy resource that cannot be used
up.
• Because the Sun will produce energy for
billions of years, solar energy is an
inexhaustible energy resource.
• Solar cells can be placed on the roof of a
building to provide electric energy.
Renewable Energy Resources (cont.)
• Wind energy is another inexhaustible
energy resource.
• Modern wind turbines convert the kinetic
energy in wind into electric energy.
• Thermal energy from inside Earth is
called geothermal energy.
• In a few places, wells can be drilled to
reach geothermal reservoirs.
A geothermal power plant transforms the
thermal energy from inside Earth into
electric energy.
Conserving Energy Resources
• Fossil fuels provide about 85 percent of
the energy used in the United States.
• Because the supply of fossil fuels is
decreasing, there could be shortages of
fossil fuels in the future.
• Conserving energy is one way to reduce
the rate at which all energy resources
are used.
About 93 percent of the energy used in the
United States
comes from
nonrenewable
energy
resources—
fossil fuels and
nuclear energy.
Conserving Energy Resources (cont.)
How does conserving energy
affect the rate at which energy
resources are used?
• Nonrenewable energy resources,
such as fossil fuels, are used faster
than they are replaced in nature.
• Renewable energy resources are
replaced in nature as fast as they
are used.
• Conserving energy, such as driving
fuel-efficient cars, is one way to
reduce the rate at which energy
resources are used.
What is the term for an energy
resource that is available in
limited amounts or that is used
faster than it is replaced?
A. nonrenewable energy resource
B. renewable energy resource
C. inexhaustible energy resource
D. alternative energy resource
What is the name for thermal
energy that comes from inside
Earth?
A. solar energy
B. hydroelectric power
C. geothermal energy
D. fossil fuels
How much of the energy used in
the United States comes from
fossil fuels?
A. about 15 percent
B. about 35 percent
C. about 55 percent
D. about 85 percent
Do you agree or disagree?
5. Nuclear power plants release many
dangerous pollutants into the air as
they transform nuclear energy into
electric energy.
6. Thermal energy from within Earth can
be transformed into electric energy at a
power plant.
Key Concept Summary
Interactive Concept Map
Chapter Review
Standardized Test Practice
Energy is the ability to
cause change. Energy
resources contain
energy that can be
transformed into other,
more useful forms of
energy.
Lesson 1: Forms of Energy
• Energy is the ability to
cause change.
• Kinetic energy is the energy
a body has because it is
moving. Potential energy
is stored energy.
• Different forms of energy include thermal energy
and radiant energy.
Lesson 2: Energy Transformations
• Any form of energy can be
transformed into other forms
of energy.
• According to the law of
conservation of energy, energy
can be transformed from one
form into another or transferred from one region to
another, but energy cannot be created or destroyed.
• Friction transforms mechanical energy into thermal
energy.
Lesson 3: Energy Resources
• A nonrenewable energy resource is an energy
resource that is available in a limited amount and
can be used up.
• A renewable energy resource
is replaced in nature as fast as,
or faster than, it is used.
• Conserving energy, such as
turning off lights when they are
not needed, is one way to
reduce the rate at which energy
resources are used.
Which term describes the ability
to cause change?
A. energy
B. friction
C. motion
D. work
Which type of energy is due to
the motion of particles that make
up an object?
A. thermal energy
B. sound energy
C. radiant energy
D. kinetic energy
What is a force that resists the
sliding of two surfaces that are
touching?
A. friction
B. kinetic energy
C. waste energy
D. work
Most of the chemical energy
used in cars ends up as what kind
of energy?
A. waste energy
B. thermal energy
C. radiant energy
D. electric energy
What term refers to an energy
resource that cannot be used up?
A. exhaustible energy resource
B. renewable energy resource
C. inexhaustible energy resource
D. nonrenewable energy resource
What is another term for light
energy carried by
electromagnetic waves?
A. electric energy
B. mechanical energy
C. radiant energy
D. thermal energy
Work depends on what two
factors?
A. force and mass
B. mass and distance
C. force and distance
D. speed and mass
Which is true according to the law of
conservation of energy?
A. Energy can be created and destroyed.
B. Energy can be created, but not
destroyed.
C. Energy cannot be created or destroyed.
D. Energy cannot be created, but can be
destroyed.
Friction between a bicycle’s brake
pads and the moving wheels
transforms mechanical energy
into what kind of energy?
A. chemical energy
B. electric energy
C. potential energy
D. thermal energy
What are the remains of ancient
organisms that can be burned as
an energy source?
A. solar energy
B. hydroelectric energy
C. fossil fuels
D. inexhaustible energy resources