Build a Balloon Rocket that Blasts Off!

When you purchase something online, typically they come in bulk to make shipping worth.

And that’s how we end up with 100 balloons.

So in search of finding activities with balloons, the balloon rocket that shoots across the room often comes up. But we already did that one. My son then chimed in, “but shouldn’t rockets shoot upward?”

And that’s how we end up doing a balloon rocket that blasts off up into the air!

Balloon-Rocket-Experiment-4

This balloon rocket activity is super easy to make and uses things you have around the house. AND IT REALLY WORKS. Make sure you get the chance to launch your balloon rocket outside so that you can see how high it can fly!

How to Make a Balloon Rocket

Materials:

  • A thick straw (I used a bubble tea straw)
  • Small rubber band
  • Balloon
  • Cardstock paper
  • Scissors
  • Tape

Directions:

  1. Place the balloon over the mouth of the straw. 
  2. Fasten a rubber band around the balloon so that no air escapes when you blow into the straw.  **I used my daughter’s hair elastics because they are tiny. If you use a bigger rubber band, you will have to go around the balloon many times to make it secure.
    Balloon-Rocket-Experiment-Rubber-Band
  3. Cut 4 rectangles out of the cardstock paper. My rectangles are about 2” x 1.25” but you really don’t need to be exact when it comes to measuring the dimensions as long as the 4 rectangles are the same.
  4. Tape the 4 rectangles to the bottom of your straw (these are the rocket’s fins). **Remember to leave a little room at the bottom so you can blow up the balloon.
    Balloon-Rocket-Experiment-Fins
  5. Blow up the balloon. You may need to put your fingers on the rubber hand to hold the balloon against the straw while you blow. 
  6. Hold your thumb against the straw opening to prevent air from escaping. You can put two fingers where the rubber band is and squeeze the straw shut.
    Balloon-Rocket-Experiment-Hold-Balloon-Shut
  7. Hold your rocket vertical.
  8. Let go and watch your rocket blast off!

If you do not have rubber bands at home, you can use tape. Just make sure to cut off the lip of the balloon so you can tape the balloon securely onto the straw.

There are so many experiments you can do with this activity. You can try:

  • Shooting the rocket without any fins. 
  • Shooting the rocket with small fins.
  • Shooting the rocket with big fins.
  • Shooting the rocket with fins with different shapes
  • Shooting the rocket with two sets of fins (eight fins total).
  • Shooting the rocket with only two fins.
  • Holding the rocket vertical at blast off.
  • Holding the rocket horizontal at blast off.
  • Throwing the rocket to give it an extra boost at blast off.

Science Behind the Balloon Rocket

Besides Newton’s first law at work (explained in the balloon-powered LEGO cars experiment), the key to making this balloon rocket blast off into the air is actually the fins.

The fins help keep the rocket stable and keep going in the same direction. When a rocket is flying through the air, the changes in the air can make the rocket wobble and go off course. 

Therefore, having the right size, shape, and number of fins can majorly affect the performance of a rocket.

If you tried shooting the balloon rocket without any fins, you can see that it doesn’t really fly high. It tends to fly wildly just like what happens when you let go of a blown-up balloon.

When you have fins on the rocket, even though the fins may not be perfect, you can tell that the rocket now travels in one direction at least for a second or 2 before changing directions. And when it orients itself the right way, the balloon rocket can fly HIGH!

Balloon-Rocket-Experiment-Flying-Balloon

Final Thoughts on the Balloon Rocket Experiment

This balloon rocket activity is a great way to encourage kids to go outdoors. Even though you can launch your rocket indoors, the ceiling is going to restrict just how high the rocket can go. 

Just make sure you don’t launch the rocket too close to the house. We almost got ours stuck on the roof! But that shows you how high the rocket can go – for us, it reached the second floor of our house.

Happy blast off!

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Balloon Rocket Blast Off Step-By-Step Tutorial

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