Let’s make a balloon rocket with things you have around the house to explore Newton’s Third Law. This simple science experiment balloon experiment is a rocket that can be constructed in your backyard or on the playground with just piece of string or fishing line, a water bottle, tape, straw and a balloon. Kids of all ages will love this science activity including older kids. I am doing it with preschoolers today.

How to make a balloon rocket - three steps shown with straws on string tied at the string ends, adding a balloon to the straw and child chasing balloon rocket path
Let’s Make a Balloon Rocket Today!

Balloon Rocket for Kids

My kids are fascinated by all things outer space and real rockets (even if it doesn’t directly relate to Star Wars).  Today we are bringing NASA into our backyard through the magic of fishing line, straws and balloons.  

It is just like Apollo 13 only without the danger.

Related: Science projects for kids

What Is Newton’s Third Law?

Sir Isaac Newton is known for his three laws of motion which was published many, many years ago in 1686. His first law is about an object at rest, his second law is about how force equals mass times acceleration and his third law of motion is:

For every action, there is an equal and opposite reaction.

-Sir Isaac Newton

Let’s build a balloon rocket to explore how one action (the full balloon’s air escaping) creates an opposite direction (the balloon rocket moving)!

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How to Make a Balloon Rocket

Supplies Needed to Build a Balloon Rocket

Directions to Make a Balloon Rocket

Get your supplies together and cut the drinking straws into smaller pieces.

Step 1

String your fishing line between two objects in your backyard 80 to 100 feet apart tying one end of the string to the secure object.

Make a balloon rocket step 1 - string up the fishing line or cotton string and lace the straw pieces on before tying the end of the fishing line or end of the string to the tree or pole
Thread the straw pieces on the end of the string before tying at one end.

Step 2

Before you attach the second end of string, thread the fishing line through two of the straw pieces so they can slide on the line.

Balloon rocket water bottle - make a balloon rocket step 3 - attach the cut up water bottle piece to the straw piece with tape
Secure the water bottle ring to the straw piece with tape.

Step 3

Take the water bottle and cut off each end so that you are left with a 3-4 inch ring. Tape this ring onto one of the straw segments.

Step 4

Next get your balloons.

Note:   Please learn from my mistake. When I went to the store for long balloons I bought the ones that are for making balloon animals. When I got home I realized that those are impossible to blow up without a pump of some sort. I needed bigger balloons! So, from here on out, I am showing you how to do this with round balloons which won’t be nearly as effective as traditional long balloons or inflated balloon animal ones!

Balloon Rocket with balloons - two balloons - one is on the inside of the water bottle ring and the other is on the outside to create a two step propulsion for rocket
The two balloons will create a two step propulsion for the balloon rocket flight!

Step 5

Blow up one balloon and then hold it in the ring not letting the air escape while you put a second balloon in place.

If done with the right balloons and better coordination, the second can be positioned so that it stops the air escape from the first. Each balloon will hold different amounts of air.

Balloon Rocket launch with two balloons - final step of building a balloon rocket
10, 9, 8, 7, 6, 5, 4, 3, 2, 1…Blast Off!

Balloon Rocket Launch

Release the second balloon….the air escapes! The balloon rocket moves! We watched the rocket fly!

Whoooooosh!

The second balloon propels the rocket and the rocket travels forward and then as it gets smaller, the first balloon takes over.

Stage one!

Stage two!

Balloon Rocket lift off - balloon air escaping to push rocket travel down string
Watch the balloon rocket thrust force with balloon air to the end of the fishing line!

Reusable Balloon Rocket

We launched the balloon rocket over and over and over. Each time watching the pushing force of the air rushes that created our rocket engine.

On the subsequent launches, I used just one balloon because it was easier to set up and I had very enthusiastic astronauts.

Balloon Rocket traveling to the end of the string with child following and trying to catch it
Can you catch the balloon rocket?

Why the Balloon Rocket works

Why does this happen? For every action, there is an equal and opposite reaction. This principle observed by Newton, lies at the heart of rocket (in this case, balloon rocket) science. The air escaping the balloon out the back pushes the rocket forward in an opposite direction. The force of the balloon air escaping is the same as the forward motion force that pushes the travel.

Printable instructions for this balloon rocket experiment.

Questions Kids Might Have about Newtons Third Law

  1. What is Newton’s Third Law?
  2. Can you explain it in simple words?
  3. Who is Newton and why is he important?
  4. How does Newton’s Third Law work in everyday life?
  5. Can you give me an example of Newton’s Third Law?
  6. Does this law work for everything or just some things?
  7. What happens when I push or pull something?
  8. Why do things move when we push or pull them?
  9. If I push my friend on a swing, does the swing push back?
  10. How does this law help us understand how things move?

Keep in mind that Kindergartners, first-third graders might not fully understand the scientific concepts behind Newton’s Third Law, so it’s important to provide simple, age-appropriate explanations and examples to help them grasp the idea.

How do I make the balloon rocket go faster or farther?

  1. Increase the air pressure inside the balloon: Inflate the balloon with more air to increase the pressure inside. More air escaping the balloon will generate a stronger force, propelling the rocket faster and farther. However, be cautious not to overinflate the balloon, as it may burst.
  2. Use a larger or longer balloon: A larger or longer balloon can hold more air, which means it has the potential to generate a stronger force when the air is released. Experiment with different balloon sizes to find one that optimizes speed and distance.
  3. Reduce friction: Ensure that the string or line used for the rocket’s path is tight and smooth to minimize friction. Lubricate the straw with a small amount of dish soap or cooking oil to help it slide more easily along the string.
  4. Streamline the rocket: Make sure the straw or tube connecting the balloon to the string is lightweight and has a low profile to reduce air resistance. You can also tape the balloon’s neck in a straight line along the straw to minimize drag.
  5. Optimize the angle: Experiment with different angles of the string or line to find the most efficient trajectory for the balloon rocket. A slightly upward angle may help the rocket travel farther.
  6. Use a nozzle: Attach a small nozzle or straw to the opening of the balloon to control the release of air more effectively. This can help direct the escaping air more precisely, generating more thrust and potentially making the rocket go faster and farther.

Challenging kids to make adjustments to their balloon rocket design is a great way to learn about the factors that affect the speed and distance of a balloon rocket.

Related: Use our scientific method for kids worksheets to test different balloon rocket designs!

Why does the air inside the balloon make the rocket move?

The air inside a balloon wants to escape because of the difference in air pressure between the inside of the balloon and the outside of the balloon. When you blow up a balloon, you are forcing air molecules into the confined space inside, causing the air pressure inside the balloon to increase. The elastic material of the balloon stretches to accommodate the increased air pressure.

The air pressure inside the balloon is higher than the air pressure outside the balloon, which creates a pressure gradient. The air molecules naturally try to move from an area of high pressure (inside the balloon) to an area of lower pressure (outside the balloon) to equalize the pressure difference.

When you let go of the balloon opening and allow the air to escape, the high-pressure air inside the balloon rushes out through the opening, creating an action force. As the air escapes, it exerts a force on the air outside the balloon.

According to Newton’s Third Law, the escaping air’s force has an equal and opposite reaction force. This reaction force acts on the balloon, propelling it in the opposite direction of the escaping air. The balloon moves forward as a result of this force, functioning like a rocket.

How does the balloon rocket relate to Newton's Third Law?

This balloon rocket science activity demonstrates Newton’s Third Law of Motion in action. Newton’s Third Law states that for every action, there is an equal and opposite reaction. In our balloon rocket activity, this principle can be seen when the air inside the balloon is released, causing the rocket to move in the opposite direction.

When you inflate a balloon and then let it go without tying the end, the air inside the balloon rushes out. As the air is pushed out of the balloon (the action), it exerts an equal and opposite force on the balloon itself (the reaction). This force propels the balloon in the opposite direction of the escaping air, causing the balloon to move forward like a rocket.

This balloon rocket science experiment is one of my favorite examples of Newton’s Third Law in action! It demonstrates how the force of the air escaping from the balloon results in an equal and opposite force that propels the balloon forward. This hands-on activity can help children better understand the concept of action and reaction in a fun and engaging way.

Is it safe to make and play with balloon rockets?

Yep! It is generally safe to make and play with balloon rockets because they are propelled by balloons. Obviously, younger children who might put a balloon in their mouth should not participate without adult supervision as this is a choking hazard. The other less-obvious danger is allergies. Some children have an allergy to latex which is a common material used in balloons. You can find latex-free balloons if needed.

More Rocket Fun from Kids Activities Blog

Or if your child enjoys balloon painting, here are 22 balloon painting activities.

Did you have fun with Newton’s Third Law and your homemade balloon rocket?



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5 Comments

  1. We love space here as well! My son loves toying around with Google Earth and switching from the Earth view to other views. Is that something you’ve played with? I seriously love the excitement captured in the first picture! That’s an amazing picture 🙂 I’ve stumbled and pinned and will definitely be sharing. Thanks for posting.