How to Demonstrate Newton's Third Law of Motion using a Paper Car & a Balloon

Learn how to demonstrate Newton's Third Law of Motion using a paper car and a balloon with the instructions in this Howcast science project video.

Have you ever been on a skateboard? Now, think about it. When you’re on the skateboard, to get the skateboard to go, you move your foot backwards and the car goes forwards.

That is exactly how rockets work. There’s an action; you going back. And there’s an opposite reaction, you’re going forward. Now think about a rocket ship. Something is pushing down, and the rocket goes up.

But do rockets always have to go up? Could we make a rocket go, that way? I want to show you how we can make a rocket balloon car that works on the exact same principles as a rocket ship. There’s an action, and there’s an opposite reaction.

And the best part about this all, you have all the stuff pretty much in your home, paper that I’m going to use just to make the body. And I’m only going to show you how to make the body and attach the wheel. And then I’m going to show you one that I have already made before because I don’t need to show you how to make the walls and all that extra fun stuff.

But making the body is important because you want your rocket balloon car to move fast. So, I’m going to make my rocket balloon car skinny and long and has to have wheels and axles. So, look what I’m going to do, candy. I’m going to show you how I could use regular candy and straws and create something called a simple machine. So we’re actually making two connections, okay; flying rockets, simple machines.

And I’m going to take a straw, and I’m going to attach it to my paper. And you could tape it down or you could use glue. I’m going to use an actual glue gun just because, to me, I think it works better. I’m just going to glue it down.

This is going to be my axle. Cars do not just run with their wheels, right? The wheels are attached to something. I’m going to push this out, just like this. And then, I’m going to put this back here. And now I have my axles done.

Now, they’re a little too long. So, what I’m going to do is attach my wheel and attach my wheel. Now you need something to hold your wheels in place. And that’s where your Scotch tape comes in. It could be masking tape, duct tape, any tape. And take a piece of tape and you’re going to wrap it around just so that it becomes thicker than the hole of the candy. And now your wheels cannot escape.

And then, you’re going to do it two times, three times, and four times. Trim off your ends. Trim off your end. And you’re going to do it to this side and this side. And then, you’re going to have your wheels.

But the cool part is you can have fun. After you’re done, you could build walls to your rocket balloon car. You could make it pointy so that it can cut through the air.

But how’s it going to move? Well, one balloon and my straw, and I’m going to make a rocket balloon car because right now, I have my car. And I have this simple machine to wheel and axle and it’s ready to rock.

Now I’m going to take my straw, I’m going to cut about an inch of the balloon. I’m going to wrap the rubber band five times. But if you wrap the rubber band too many times around the straw, the straw will close, and the air will not be able to go into the balloon or out. So, you’ve got to be aware of that.

One, two, three, four, five – I’m going to try six. Now, I’m going to test it and listen to see if any air is escaping and if it’s not, let the air out. And now, I’m going to attach my rocket balloon to here. And I’m going to tape it down.

Now some of you still are not getting what’s about to happen, but watch this. Now that this is taped, think about this. What if I fill up the balloon?

Now think about this guys. The more air you put into the balloon, and I let the air out, the air is going to escape out of the straw and go which way? That way. So, according to Newton’s third law of motion, "For every action there’s an opposite reaction," if the air is going that way, my car should go the opposite way.

So, let’s try it. In three, two, one. Ah, and there’s your rocket balloon car.