Conservation of Energy

Have you ever pushed your toy car and watched it go, go, go... and then slow down. Where did its zoomy power go. Or have you seen a flashlight get dimmer and dimmer. The light didn't just disappear. I know the secret. I am a very special rule for the whole world. My rule is that energy never, ever gets lost. It just changes into something new and different. It's like a magic trick, but it's real. The energy is always there, just hiding in a new way.

For a very long, long time, people did not know my secret rule. It was a big mystery. Then, a long time ago in the 1840s, some very smart and curious people started to figure me out. A kind doctor named Julius Robert von Mayer saw that energy could change from one thing to another. Another smart person, James Prescott Joule, showed everyone that moving energy could turn into warm, cozy heat. You can feel it when you rub your hands together really fast. They get warm. That's me. I showed them that energy just likes to wear different costumes. It can be electricity in a lamp, and then...poof. It changes its costume to be bright, happy light. The yummy food you eat has energy, and it changes its costume to give you energy to run and jump and play all day.

So that's me. My big name is the Conservation of Energy. I am a very important rule that helps everyone, everywhere. Because of my rule, we know that the big, bright sun gives energy to the little plants to help them grow big and strong. Then we eat the plants, and they give us energy to live and play. I help remind you to be smart with our world's energy. When you turn off the lights when you leave a room, you are helping save that energy. Understanding my secret helps us all take care of our wonderful planet and keep our world full of power and light.