Energy causes things to happen around us. Look out the window.
During the day, the sun gives out light and heat energy. At night, street lamps use electrical energy to light our way.
When a car drives by, it is being powered by gasoline, a type of stored energy.
The food we eat contains energy. We use that energy to work and play.
We learned the definition of energy in the introduction:
"Energy Is the Ability to Do Work."
Energy can be found in a number of different forms. It can be chemical energy, electrical energy, heat (thermal energy), light (radiant energy), mechanical energy, and nuclear energy.
Next chapter is about Electricity.