 Welcome back to Kids Fun Science. My name is Ken and today's experiment is heat from friction. As always, adult supervision is required. What you need for this experiment is a pen, a dowel, a cardboard, a wire hanger, and wire cutters. Welcome back to Kids Fun Science. Today we're going to do an experiment about friction. If you take your hands and rub them together really quickly, you're going to know something. You're going to notice that they start warming up as you're watching this video. Well, how does this happen? Well, any object, no matter how smooth it is, if you rub them together, they're going to produce friction. Friction is a force that is opposite motion that causes tiny imperfections and surfaces to run over each other. In this experiment, I'm going to show you how we can explore friction in multiple different ways. What we're going to use is a wooden dowel, a pen, a piece of cardboard, and a wire coat hanger. And we're going to do friction on each one of these. All right, so we're going to start off with the wooden dowel first. Friction can be caused by rubbing something very quick together. And if you just kind of lightly grip it, you're not going to get as much friction, but the harder you grip it, and the faster you move it, the more friction you're going to get. So I start off slowly first, and I really don't feel too much there. It's a little warm, not much, but if I hold it tighter and go back quicker, I can really feel it starting to get warm. And it actually goes away pretty quick with the wooden dowel. So let's try a piece of cardboard, and same thing, slow. You don't feel it as much. It's not that warm. If I squeeze down and do it fast, I can start to feel it, and it actually kind of stays in the cardboard where the wood, it went away a little bit, but you can still feel, I can still feel the heat inside the cardboard because of the friction. Alright, so I have two more left. I have the hanger, and I have a plastic pen. So when we do the plastic pen, I take the cap off, and I start moving it back and forth lightly. I don't really feel it, but if I hold it tighter and move it back really quick, I can start feeling it get really hot, and I can still feel it, but it kind of goes away after a little bit where the cardboard held the heat for a lot longer, and the wooden dowel didn't hold the heat at all. It got hot, but it went away really quick. So now we're going to try the metal hanger right here, and go like this, and I'm squeezing really hard this time, because I know light is not. It's starting to feel really hot. That was super hot, and oh my god, that is still hot. So the metal, of course, is holding the heat a lot quicker, or holding it a lot longer, and getting a lot hotter on here, which is amazing. And then I have one more experiment I want to do, is I want to cut this metal, and I'm going to do one more experiment after that. The science behind this is the harder you press, and the faster you rub, the more friction, and therefore the more heat you generate. Rubbing the materials uses kinetic energy, which is then transferred into heat energy as the atoms in the material move and vibrate. The different materials transfer different heat. So we take the hanger, we want to cut it about a six inch gap here. So we'll cut it here, and then cut it down on the bottom here to get about a six inch gap. There we go, put that right here. And so now with this, I'm going to try to do is bend it back and forth, and see if we can get heat generated by moving it back and forth. And it's a little harder than I thought, but if you go quicker, I could really, oh my gosh, that is super hot, right there. I wasn't even touching this piece, I'm just moving it back and forth, but the wire bending back and forth is extremely warm. That was probably the hottest it was. That was amazing. And all I was doing is bringing the metal up and down. So I do it again. I can already feel it and get it warm up here. It's coming down the side of the metal. The faster you go, oh wow, that was very hot. Be careful. This is actually that was really hot just by moving up down very, very impressive by not even rubbing it, but just the friction itself, releasing that kinetic energy. So the science behind this is when you bend the metal wire back and forth like this, there is no surfaces rubbing together. But within the metal there are atoms of copper or whatever wire you've found, they're still passing each other. So the rapid motion is chugged into heat, and the metal being a great conductor of heat will pass that heat along itself. All right, well, I hope you enjoyed this video. Make sure you try this one, but be very careful. You might even want to wear gloves with this one. It got extremely hot on here. If you like this experiment, click thumbs up and share. And thanks for watching.