How Energy Changes Form

By the end of this lesson, you will be able to describe how energy changes from one form to another inside a system.

Energy is the ability to make something move, heat up, or light up. Energy does not disappear, but it can change form. When energy changes form, we call that an energy transformation. This happens all around you, every day.

Think about a flashlight you might grab during a Texas thunderstorm when the power goes out. Inside the flashlight are batteries. A battery stores chemical energy, which is energy held in the materials that make up an object. When you slide the switch on, the chemical energy in the battery changes into electrical energy, which is energy carried by moving electric charges. That electrical energy travels through wires to the bulb. The bulb changes it into light energy, so you can see your way down the hallway. You may also feel the bulb get a little warm, because some of the energy turns into heat.

Notice that the flashlight is a system. A system is a group of parts that work together. The battery, switch, wires, and bulb all do their own job, and energy moves through them in order. If you take out one part, the system stops working.

Once you know the pattern, you can spot it in other places. A ceiling fan changes electrical energy into motion. A car engine changes chemical energy in gasoline into motion and heat. A solar panel on a school roof changes light energy from the Sun into electrical energy. Your own body changes chemical energy from food into motion and heat when you run at recess.

Try it: When you turn on a battery-powered toy that plays music, name the three forms of energy in order, starting with the chemical energy in the battery.