energy

What is Energy?
 The simplest definition of energy is "the ability to do work". Energy is how things change and move. It's everywhere around us and takes all sorts of forms. It takes energy to cook food, to drive to school, and to jump in the air.

 Different forms of Energy
 Energy can take a number of different forms. Here are some examples: 
Chemical - Chemical energy comes from atoms and molecules and how they interact.

 Electrical - Electrical energy is generated by the movement of electrons. 

Gravitational - Large objects such as the Earth and the Sun create gravity and gravitational energy. Heat - Heat energy is also called thermal energy. It comes from molecules of different temperatures interacting.

Light - Light is called radiant energy. 

source:http://www.ducksters.com/