Energy _______________________________________________________________________________________________________________________________________________________________________________________________________________________ 2. Definition of energyFigure 6.1
When you see changes in the world around you, you are seeing evidence, or proof, of energy.
Look at the picture. What changes do you think are happening?
- As the wave crashes onto the shore, the water moves. That is one change. - Imagine you are there on the seashore. You hear the sound of the water splashing against sand and rocks. The sound changes because of the movement of the water and the wind. - Another change is the movement of the sand as it is pushed by the water. - And there’s a change happening that you can’t see—the temperature of the sand is changing as it is warmed by the bright sunlight or cooled by the water.
All these changes are caused by some form of energy.
DEFINITION OF ENERGY
Whenever there is a change, there is some form of energy causing the change.
Energy is the ability to cause change.
Energy is a quantity that is transferred from system to system.
Energy is also defined as the ability of a system to do work or transfer heat.