Answer Key Energy and Energy Transformations

Reading Essentials

Answer Key

Energy and Energy Transformations

Lesson 1

Before You Read

1. Agree 2. Disagree 3. Disagree

Read to Learn

1. the ability to cause change 2. The car on the right has more kinetic energy because it is

moving faster. 3. energy due to motion 4. b. mass and height above the ground 5. Students should circle the vase on the top shelf. 6. a. jumping on a pogo stick 7. Gravitational, elastic, and chemical potential energy are

different types of stored energy. 8. Students should highlight some of the lines in the figure that

represent chemical bonds. 9. when the girl lifted the box onto the shelf 10. Work is the transfer of energy that occurs when a force is

applied to an object. 11. when you move the rock 12. Students should circle the block of ice. Possible answer: The

block of ice is melting because thermal energy is moving from the air to the block of ice. 13. b. waves that can travel through a vacuum 14. Possible answer: Electric energy is the energy carried by an electric current; radiant or light energy is carried to Earth from the Sun through electromagnetic waves; nuclear energy is stored and released in the nucleus of an atom.

After You Read

1. Possible answer: Energy is the ability to cause change, and work is the transfer of energy when a force makes an object move.

2. Kinetic: energy due to motion Electric: the energy an electric current carries

Energy and Energy Transformations

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Mechanical: the sum of potential energy and kinetic energy in a system of objects Nuclear: energy that is stored and released in the nucleus of an atom Potential: stored energy due to the interactions between objects or particles Thermal: the sum of kinetic energy and potential energy of the particles that make up an object Radiant: energy that electromagnetic waves carry Sound: the energy that sound carries

Lesson 2

Before You Read

4. Agree 5. Disagree 6. Agree

Read to Learn

1. Radiant energy changes into thermal energy in the kernels. 2. at point C, the ball's highest point 3. Energy can be transformed from one form into another or

transferred from one region to another, but energy cannot be created or destroyed. 4. Total energy is constant because the total amount of energy never changes. 5. Friction transforms mechanical energy into thermal energy. 6. 0.3 kWh 7. Possible answer: Thermal energy can be used to cook and provide warmth; chemical energy can be used to turn food into kinetic energy for movement or into thermal energy to keep the body warm; sound energy, electric energy, and radiant energy are used by cell phones; electric energy is used to power electric devices. 8. thermal energy that cannot be used

Reading Essentials

Energy and Energy Transformations

2

After You Read

1. Possible answer: Rubbing two sticks together to create fire is an example of friction.

2.

Energy Change

Example

Energy Change

Example

Kinetic to potential

Throw a ball into Chemical

the air.

to thermal

Your body uses food to keep it warm.

Electric to A space heater

thermal

warms a room.

Sound to radiant

A call is received on a cell phone.

Potential to An object falls to Electric to A lamp lights a

kinetic

the ground.

radiant

room.

Chemical to electric

A batteryoperated mp3 player plays music.

Chemical to kinetic

Food is digested to help a person move.

3. Possible answer: Friction can cause mechanical energy to change to thermal energy.

Reading Essentials

Energy and Energy Transformations

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