The Sun's energy reaches Earth as ______________.

• heat energy and light energy
• kinetic energy and light energy
• kinetic energy and chemical energy
• electrical energy and chemical energy

What happens when we burn fuels such as coal and gasoline?

• We change heat energy to light energy to do work.
• We change kinetic energy to heat energy to do work.
• We release the potential energy within them to do work.
• We release the electrical energy within them to do work.

Which of these objects has kinetic energy?

• car moving on a road
• skier going down a slope
• ball rolling down a ramp
• all of the above

What happens to the chemical energy in the battery when you use an electric toothbrush?

• It changes into kinetic energy and then potential energy.
• It changes into potential energy and then kinetic energy.
• It changes into electrical energy and then kinetic energy.
• It changes into kinetic energy and then electrical energy.

What is an electric circuit?

• the movement of electric energy
• an outlet you can plug a cord into
• the path that an electric current flows through
• a machine used to change sunlight into electricity

What is the trough of a wave?

• the top of the wave
• the width of the wave
• the length of the wave
• the bottom of the wave

What happens when a warm object comes into contact with a cool object?

• The cool object loses heat.
• The warm object gains heat.
• The warm object loses heat and the cool one gains heat.
• The cool object loses heat and the warm one gains heat.

When can you notice friction?

• when wood bruns
• when sunlight warms the sand at a beach
• when you heat frozen vegetables in a pot on the stove
• when you warm your hands by rubbing them together

How does heat make liquid water change?

• The liquid water becomes ice.
• The liquid water becomes a solid.
• The liquid water evaporates and disappears.
• The liquid water evaporates and becomes a gas.

What is a chemical change that gives off light and heat?

• boiling
• burning
• freezing
• evaporating