 Hi, I'm Ashley from the North Carolina School of Science and Mathematics. Today we're going to talk about balance and motion. I'll show you some things that can be a lot of fun and help you understand more about these ideas. When we're finished, you'll have a better understanding of gravity, balance, and the center of gravity. We'll also talk about the word symmetry, a word you might not know, what it means, and how it relates to what we'll learn. These are the things you'll need to do the activities in the video. Let's look at how something balances. Pretend this piglet is performing in a circus in a high wire act. If she wasn't balanced, she would fall off the wire. Do you see where her hands are? Why do you think she's holding them out? It all gets back to balance. It's easier when you hold out your arms and hands when you're trying to balance on something. Piglet is doing that so she can shift her weight and center of gravity more easily. We'll learn about the center of gravity later. You are balanced even when you're standing right there on the floor where you are now. If you lose your balance, what happens? The earth's gravity pulls you down and you fall over. Gravity is the invisible force that pulls objects towards the center of the earth. It takes a lot of practice to balance on something like piglet is doing. Have you ever seen a toy like this? It's a balancing toy. Do you see how it stays balanced on this point and spins around so easily? It's because he's balanced perfectly on a point. The toy will also introduce us to the word symmetry. An object is symmetrical if it can be cut or folded in half and both sides are exactly the same. You can see the bird has symmetry. The two sides are the same when you look at it like this. So it is what we call symmetrical. Now let's take these ideas and make something you can try. You'll need a paper cutout like this one and some paper clips. The construction paper cutout we made looks like a person doing a handstand. What letter does it look like? What happens when you split it in the middle? Just like the toy, our figure is symmetrical. It's the same on both sides. Now take the paper cutout and try to rest it on its nose so it balances on your finger. Can you get it to stay there? Do you have any predictions on what might happen if you put the clips at different places around the cutout to help it balance? Test your predictions by trying the clips at various places on the cutout. Move them around different spots until the cutout balances on your finger. When you test your hypothesis, you're doing a scientific experiment. Did you get it to balance? Adding a clip to the only one hand adds weight, but it doesn't add equal weight to each side. This causes the cutout to fall off your finger. Gravity pulls it down on the side with the paper clip. You probably discovered that it works best with the paper clips on the two lowest points on the cutout, like this. Here, we have a really big cutout we call balancing Bernie. Let's use Bernie to further demonstrate what we just learned. First, what shape does Bernie remind us of? Yep, it's the letter Y. Do you remember that the cutout you used in the last experiment resembled a Y as well? Bernie and the letter Y also share a special descriptive word about how they're shaped. We learned it earlier. It's a word that means if an object is folded or cut in half, it's the same on both sides. Remembering what we did earlier, if we take these clips and place them somewhere on him, where would you place them for Bernie to do a headstand? At the top? How about the middle? Let's try along the bottom like we did before. Now Bernie is balanced with the weight below his head. His head is now the balance point and the weight is equal on both sides. Let's try something a little different. What if you put a weight on his foot and won by his hand? Where along his body would you place your finger so that Bernie balances? Where would the balance point be? Right about here. The weight is the same on both sides of the balance plate. People are balanced too and not just when they're walking on a high wire. Now stand up right and keep your hands close at your sides and lift your foot off of the ground. Be careful. Is it harder or easier to keep your balance when you're standing on one foot? Try it again holding your arms out. Is it easier or harder? Your arms are helping you balance your weight. Your balance point is the foot you still have on the ground. You're also balancing when you do other things like skateboard or ride a bike. When you stand with your arms out, it helps keep the amount of weight the same on each side of your body. What happens if there's more weight on one side than the other? Gravity takes control and you fall over. Hey, here's a cool fact you might not know. Special bones and nerves in your ears send messages to your brain to help you stay balanced. If you have an ear infection, this can affect your equilibrium, a fancy way to stay balanced, and you can get dizzy and fall down. Let's try another experiment. To do this, you'll need a popsicle stick, some wire, and some hex nuts. You can use these objects to make a toy that works a lot like the bird toy we saw at the beginning of the video. First, try balancing the popsicle stick on your finger. Can you do it? Now try it with the popsicle stick wrapped with the wire and the hex nuts attached like this. Experiment with your sticks and wire by squeezing or bending the wires around. Moving the wire along the stick. Move the hex nuts around and see how balancing the toy on your finger changes as you move the weight around. How does squeezing or pulling the wire out a little bit affect the way the weight shifts? Pause the video and try it yourself now. What did you find out when you tried it yourself? Today we've made balanced toys and done experiments that help show you how the piglet on the high wire keeps her balance and doesn't fall off. Compare the toys you made with the piglet on the high wire. How is your toy like the arms on the pig? Did you notice how the toys you just made work the same way as the piglet holding out her arms on the high wire? The wire is like the arms and the hex nuts are like the hands. By holding them out, it helps keep both the pig and the toy balanced and they don't fall over. Let's talk about some of the things we learned today. Do you remember the word gravity? What do you think it is? Gravity is the invisible force that pulls objects towards the center of the earth. We also learned about symmetry. Symmetry is when an object is exactly the same on both sides. We often describe that object as being symmetrical. Balance. Balance is the ability to keep something steady without falling over. When we talk about balancing things, we are talking about the center of gravity. This is the exact point at which all of the object's weight is evenly distributed. So today, we learned some things that might have been new to you. We got to try some experiments and we made some toys to go along with those experiments. Try to think of more experiments you can do relating to the world around you and maybe you can become a scientist yourself someday. Good luck!