Whoosh! Building a Balloon-Powered Glider in Minutes

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This balloon-powered glider has it all: it’s a simple engineering experiment with a lot of teaching ability. Plus, you only need 3 things to build it in a matter of minutes! What’s not to love about that?

This experiment demonstrates physics (Newton’s Laws), friction, and engineering design using a simple DIY balloon-powered glider.

Get to gliding!

How to make the Balloon-Powered Glider STEM experiment

Supplies you will need

For this experiment, you’ll need:

Balloon
Cut off top of plastic bottle
Bottle cap
Scissors or box cutter
Optional: marker

Before you start

Please be mindful of sharp edges around the cut-off 2-liter bottle top.

Instructions

Here is how to do this experiment with your child:

Step 1: Cut off the top of the 2-liter plastic bottle

Draw a line around the 2-liter bottle (see picture below). This part isn’t totally necessary, but it does help guide your scissors or box cutter so you know you’re cutting in a straight line.

I found a little ridge in the bottle and ran my marker around the ridge.

Cut around the bottle to remove the bottle top from the body of the bottle.

Draw a line around the bottle to know where to cut

Use scissors or box cutter (easier) to cut the line on the bottle

Step 2: Smooth out the edges of the plastic bottle

If necessary, use your scissors to smooth the edges of the bottle top that you cut in step 1.

A smooth bottom to your bottle ensures that there will be less friction and even surface area so your glider is the most efficient!

Step 3: Cut a small hole in the bottle cap (BE SURE TO READ THIS SECTION!)

STOP! Read this part carefully!

For this step, we are cutting a small hole in the bottle cap of the 2-liter bottle. THIS IS IMPORTANT: start SMALL, especially if you do not have back up bottle caps.

If you cut a hole that is too large for your glider, the air pressure will overtake the bottle and it will not glide.

Then again, if the hole is too small, there won’t be enough air pressure to help your glider glide.

The important part here is to START SMALL, test, then make the hole bigger if necessary.

Step 4: Blow up the balloon

This one’s pretty simple: blow up your balloon. This is part of the experimentation process too: see how varying levels of inflation affect the glider. Does it glide more efficiently if there is less air in the balloon or more?

Step 5: Attach the balloon to the bottle top and let it go!

Carefully pinch the balloon neck and attach the opening to the bottle cap. Be sure there are no leaks.

Place the bottle top on the tabletop or floor with the balloon facing up, give it a quick tap, and watch it glide across the surface!

Remember: if it doesn’t glide well, you may need to adjust the air in the balloon or the hole in the bottle cap.

Pinch the balloon neck and attach it to the bottle cap, ensuring there are no leaks in air

The STEM behind the Balloon-Powered Glider experiment

This experiment teaches:

Physics
Friction
Engineering design

How it works

This experiment demonstrates physics, friction, and engineering design using a simple DIY glider.

An inflated balloon, which is attached to a hole in the top of a cut-off 2-liter bottle, contains pressurized air. As the air is released from the balloon through the hole in the bottle, it creates lift in the glider, allowing it to effortlessly glide along a smooth surface.

As long as the surface of the table is smooth, there will be little to no friction to interfere with the glider. If there is any friction, the glider is hindered from moving across the surface.

This experiment is great for demonstrating Newton’s Third Law of Motion, varying levels of friction and how they affect movement, and refining an engineering design to make the glider as efficient as possible.

Physics

This experiment is a great demonstration of physics in action!

The inflated balloon has pressurized air in it. When we attach it to the bottle top, air slowly escapes through the hole we created in the bottle cap, exerting a force in one direction.

If we want to throw a little Newtonian law into the mix, we can talk about Newton’s Third Law: for every action, there’s an equal and opposite reaction. The air from the inflated balloon pushes downward (the action) and the glider generates lift (the reaction).

The amount of lift generated is directly related to the rate at which the air escapes the balloon and the size of the hole in the bottle cap. If the hole in the bottle cap is really large, there will be a lot of lift generated very quickly. If there’s only a small hole in the bottle cap, the amount of lift will be small.

This is where we have to be careful: if the hole is too small, it won’t generate enough force to lift the glider!

Another variation you could add in is the size of the balloon or the amount of air you add to the balloon. You could ask your students here what they think will happen if we only fill the balloon halfway, or if we use a smaller balloon.

What will make our glider glide for the longest amount of time? How many variations could we try?

Friction

Here’s another fun variation for our glider: control the friction!

First, if your students don’t quite understand friction, this is the time to talk about it. You could try rolling a ball on a plush rug or carpet and then roll the same ball on a tile or concrete floor. Which surface does the ball roll on for a longer distance?

Since our pushing force and the ball remain constant, the only thing that’s changed is the surface we roll the ball on. What slows our ball down on the plush carpet that keeps it from traveling farther? Friction!

Now that we have friction down, we need to apply it to this experiment.

What are some factors that could affect the friction in our experiment? Hint: there’s actually two!

The friction of the tabletop/floor/whatever we glide our glider on
The base of the glider (if it’s smooth or not)

Since we covered the first bullet point already, let’s talk through the second bullet point.

If we do not make the base of the glider completely smooth, or if it is not totally flat, our glider will experience more friction.

If the bottom of the bottle has ridges or is sticky, we are increasing the friction of our glider.

That’s why it’s important to make sure to make the bottom of the glider as smooth as even as possible!

If you want to gear the experiment toward learning about friction, you can play with these elements by increasing or decreasing the friction for your glider. Try running the glider over a carpet and a smooth table to see the difference, then ask their thoughts about what could increase or decrease the friction.

Is it more efficient to increase the friction or decrease it?

Engineering design

Engineering design is all about optimizing our glider’s performance. That involves considering factors like speed, the distance it can travel, stability of the glider, and more.

We can experiment with things like:

Bottle size and shape: Different bottle sizes and shapes can affect the skimmer’s aerodynamics and stability.
Balloon size and shape: Different balloons will hold different volumes of air, and release air at different rates.
Opening size: Adjusting the opening size allows for control over the air release rate.
Weight distribution: Adding small weights to the skimmer can improve its stability and straight-line motion.

You can also discuss the materials used in creating your glider. Why was the elastic property of the balloon important for the function of our glider? And why is smooth plastic a better choice than a steel cup?

We used an elastic balloon because the balloon can easily inflate and hold a lot of air to power our glider. We used a smooth, plastic bottle because it’s light but can still maintain its shape, allowing it to easily lift off of the surface. If we used something heavier, like a steel cup, we could not easily lift the cup with an inflated balloon.

You could also play with different bottle sizes, balloon sizes and shapes, and weight distribution to see how it changes the glider’s efficiency.