Boy, do I have a day planned for you. Swimming! Dancing! Racing! Building! You're going to need a lot of different clothes to do each one of these right, so get your wardrobe ready. We're going to see what it feels like to change like energy. Lucky for you, though, unlike energy, you don't have to move from place to place naked.
Time to swim! Put on your swimsuit, and let's go to the beach. As you swim, you can feel the heat of the sun on your shoulders. You can hear the sound of waves. Energy is moving all around you!
Waves are a kind of energy that moves through things like sound and water, and can also travel through space as light. Energy wiggles out in every direction when a wave crashes or the sun shines. Once you hear or feel these waves, they become a new kind of energy. They put on clothes.
Has anyone seen my Boogie Board?
The original uploader was Estrategy at English Wikipedia., CC BY-SA 3.0 , via Wikimedia Commons
Time to dance! Change out of your swimsuit and into clothes that let you move. Shake and bounce around and throw your arms and legs every which way. Energy does that, too.
Heat energy is a kind of energy that shakes the tiny water particles that make up things. We can see this when a wave of light warms something. The light changes into something that shakes tiny parts of the thing that are too small for us to see. We feel this shaking as heat. You can also see this heat when steam rises off something hot. The bits that make up water start to shake so much that they bounce away from the rest of the water! Or better yet, feel it as your skin begins to warm by a fire. Maybe that's why people call some dance moves "hot."
Looks like A PARTY!
Frank H. Carter, Public domain, via Wikimedia Commons
Phew! That was a lot of moving. It's time to rest. Here, rest at the top of this hill. I will tell you why later. Just like you, energy can become very still after all that moving. It does not need to move like a wave through the air. It does not need to shake. It does not need to carry anything through space. It can just sit and wait.
Potential energy is energy stored inside of a thing that can be used at a later time. Think of lifting a ball high into the air . . . but not dropping it. While it's up there, it has a lot of energy in it. You just need to let go to let the energy out. That wheel just needs a push to start rolling. That match just needs a scratch to start dancing. Now why did I have you rest at the top of the hill?
Race time! Throw on some tight clothes that will not flap in the wind or catch on anything. Being at the top of that hill gives you a lot of potential energy. Now, we are going to use it. Ready? One . . . Two . . . Three . . . SSSHHHHHHHHOOOOOOOOOM! CAN YOU STILL HEAR ME? GOOD!
Kinetic energy is the energy something has when it moves. When cars drive, rocks roll, the Earth turns, birds fly, even when you fly down this hill, you have this kind of energy. When a car uses gas, the energy in the gas turns into the energy of moving. And now that you are slowing down at the bottom of the hill, you have less and less energy.
You have different clothes to get you ready for the world. To swim. To dance. To race. To sleep. Energy also changes. It can move through the air as heat or sound. It can carry something through space. Or it can just wait inside something so it can be used someday. Just be glad that whenever you move from one place to another, you don't have to go there naked.
References Burn, An Energy Journal. "Forms of Energy: Motion, Heat, Light, Sound." Burn, 2012. <http://burnanenergyjournal.com/forms-of-energy-motion-heat-light-sound-2/>
Energy Kids. "What is Energy? Forms of Energy." U.S. Energy Information Administration, 2013. <http://www.eia.gov/KIDS/energy.cfm?page=about_forms_of_energy-basics-k.cfm>