 Yo, so I'm here to play squash for the first time. I don't really know much about it. I hear there's a racket Probably a ball. It's a lot like tennis, which I'm pretty good at. Hey, man. Ready to go. Let's do this great Which ball do you want to use? It's all the same. Let's go with the blue one. Oh, but they're not the same I told you we should have used the blue one the black ones clearly broken. It's not broken. They're designed to bounce differently What do you mean designed differently? They're just different colors. It's not the color They're a different material. They're both made out of rubber. Sounds like you need an education in the science of bouncing When you hold a ball up high It has a certain amount of what we call potential energy When you let go and it starts to fall that potential energy gets converted into kinetic energy and the ball speeds up And when the ball gets down to the ground all of the potential energy has been converted into kinetic energy So when the ball deforms it stores kinetic energy and when the ball returns to its original shape It releases that energy making it bounce back up We call balls that deform and bounce elastic, but not all balls are like this some Like modeling clay are what we call inelastic When we drop the clay it deforms permanently and since it doesn't return to its original shape There's no way to store the kinetic energy and since there's no way to store the kinetic energy It would make a terrible material for squash balls. Exactly. There's hardly any bounce Okay, so I get why you wouldn't make a squash ball out of modeling clay that would be lame But you still haven't told me why those two rubber balls bounce differently from each other And because of that fact, I'm stuck here learning instead of beating you with squash So while these balls look similar, they're actually made out of different rubbers Let's take a look at what happens at the material level All rubber is made up of these long molecules called polymers tangled together When the ball deforms these polymers stretch out, but they quickly return to their original shape All this stretching causes the polymers to rub against each other This transforms some of the kinetic energy into heat The difference between the two balls is how tightly the polymers are tangled The looser the polymers the more they rub against one another and the more heat they produce And the more heat the less kinetic energy they have So the less kinetic energy the less bounce right on So the bouncy ball is made out of tight polymers and the other one is made out of loose polymers Exactly sweet. Let's play. You know the temperature of a ball also affects its bounce There's more definitely The warmer a ball is the stretcher the polymers and the stretcher the polymers the more bounce So is there like an oven around here or we can heat these up a bit? We don't need an oven. Remember what I told you earlier Every time a ball bounces a little bit of kinetic energy is turned into heat So if we bounce the balls a lot There'll be a lot of heat So I have agreed to stop cheating in the future and max is going to help me finish our experiment here Begrudgingly I might add so here's the ball. We've been hitting around and here's an identical one except it hasn't been bounced So it's colder So when we bounce the wait, wait, wait, I got this The warmer one's going to bounce higher. Let's see if you're right Booyah Since you're determined to teach me science today, let me make sure I got this straight A ball's bounce is determined by both its material and temperature So a stretchier and warmer ball will bounce higher You got it So let's see if you can do more than just talk about squash. Oh, you're on friend I You were nice for you you for me Love your headband your shirt's pretty cool itself. I love your sweatshirt. You were nice wig. Who bought it for you You bought it for me