| A | B |
|---|
| energy | ability to do work and make things happen |
| potential energy | stored energy |
| kinetic energy | energy in motion |
| sun | the most important energy source |
| fossil fuels | oil, coal and natural gas |
| mechanical energy | energy created by the motion of working parts |
| sound energy | energy caused by the vibration of an object |
| electrical energy | energy from the flow of electricity |
| heat energy | energy flowing from a warm object to a cool object |
| light energy | energy that travels in waves |
