# Q & A: Energy making changes

Q:
what can energy change?
- Anonymous
A:
Just about any change matter undergoes requires energy to make it happen. Some examples:

Energy can make things hot: heating up something on a stove involves adding energy to it.

Energy can make things glow: electrical energy being dissipated in a light bulb will make it glow.

Energy can make things change shape: You can fold a piece of paper, but it takes some mechanical energy to do it. Stuff that's made out of metal needs to be bent into shape, and that means energy needs to be added to bend the metal.

Energy can break stuff: Dropping a glass on a tile floor will first exchange gravitational potential energy for kinetic energy, and then finally into the energy required to break the bonds holding the glass together as it shatters.

Energy can make music: Pluck a guitar string or blow a horn -- that takes energy. Sound waves carry energy through the air to the listener.

Energy makes waves crash on the beach -- the water moves, carrying kinetic and gravitational potential energy.

Energy makes clocks run -- wind up a spring, or plug it in the wall, it takes energy to go.

Energy can change from one form to another:
Examples:

electricity -> heat in the toaster

chemical potential energy to heat in a fire

chemical potential energy to kinetic energy in a car

gravitational potential energy to kinetic energy in a falling object

Einstein's E=mc^2 says we can even turn energy into matter!

Tom

(published on 10/22/2007)