1. Conservation of Energy
SC.7.P.11 Energy Transfer and Transformations
Heat and
States of Matter
Conservation of Energy
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2. What are some examples of conservation of energy?

3. Energy is always conserved
Energy is always conserved. Kinetic energy is transformed into potential energy and vice versa.

4. Kinetic and potential energy of atoms result from the motion of electrons. When the amount of energy in a system changes (temperature), a phase change may occur.

5. Energy is continually transformed, but is never lost.

6. The creation of sound when the person lands in the sand58
Which of the following is NOT evidence of a transfer of energy that can be observed when someone steps off of a boardwalk and into the sand at the beach?
The rebound of force from compression when the person lands in the sand A B
The creation of sound when the person lands in the sand C
The movement of sand when the person lands in the sand
Answer: A D
The release of heat from friction when the person lands in the sand

7. 59
Which statement best describes what happens to a snow skier's potential energy while gliding down a ski slope? A
Potential energy is conserved and has an equal value at the top and bottom of the slope. B
Potential energy is destroyed at a rate equal to the speed the skier travels down the slope. C
Potential energy is transformed into an equal amount of kinetic energy as the skier moves down the slope.
Answer: C D
Potential energy is created in an amount equal to the change in elevation as the skier moves down the slope.

8. Sunlight heats the roof which then heats the interior.60
Joseph parks his car under a tree. His friend Miguel parks his car in the sun right next to him. The interior of Miguel's car is much warmer than Joseph's car. Which of the following best explains why Miguel's car was warmer? A
Sunlight heats the roof which then heats the interior. B
The air around the car is heated which heats up the car.
Answer: C C
Energy from light waves is trapped inside the car as heat energy. D
The light waves attract heat from the surrounding ground or pavement.

9. from the aluminum cube to the beaker61
Mrs. Aldaco added a room temperature copper (Cu) cube and an aluminum (Al) cube that she just removed from the freezer to a beaker of boiling water. She left the cubes in the water for three hours. Which of the following describes a heat flow that took place during those three hours? A
from the aluminum cube to the beaker B
from the copper cube to the boiling water
Answer: D C
from the aluminum cube to the copper cube D
from the boiling water to the aluminum cube

10. Light energy is transformed into mechanical energy.62
Which of the following is the best description of an energy transformation that occurs in a light bulb? A
Light energy is transformed into mechanical energy. B
Electrical energy is transformed into light and heat energy. C
Heat energy is transformed into light energy.
Answer: B D
Chemical energy is transformed into electrical energy.