It's funny how universe is made of energy and matter. According to Einstein they both can be related with a simply formula:
"Energy is equal to mass times squared speed of light."

Energy can be be found trough out the form of radiation which can be absorbed and emitted from many different ways.
When an object absorbs one kind of radiation it gets more "energetic" in some sort of speech.
It can also reflect some of the radiation.
Thanks to this our world is full colors.

Between green and purple, red and orange, yellow and blue, we can find millions, billions, zillions of different kinds of colors each one of it made with different amounts of energy.
Next time you look into an object, thing what makes you look at it and identify it.