Balloon Rocket Experiment: STEM Activity for Preschoolers

This balloon rocket experiment is easy to set up and use materials you probably already have in the house. This STEM experiment will teach your preschooler air and thrust.

It has been scorching hot here in SoCal. I have been avoiding going out with the kids because even getting into the car is brutal, and I am deathly scared that somehow the metal buckles on the car seats will somehow burn their little legs. However, staying inside gets boring, and bored kids equal the entire house getting flipped inside out. ARGH. I don’t want to spend tons of money on new toys just to entertain them for a few days (yup, that’s how long interest in new toys lasts in this house), so what to do, what to do??? I was determined to do something that 1) I don’t want to spend any money on, 2) is STEM-related because I am a physics nerd at heart. After some researching, the idea of balloon rockets was discovered!   How do you make these balloon rockets?

Materials:

• String (I just used the one I found around the house that is used to tie up newspapers) 
• Straw (I used a bubble tea straw because it’s nice and fat, but you can just use a regular drinking straw) 
• Tape (any will do) 
• Balloon(s)

Steps:

1. Tie one end of the string to a chair (or anything you can tie it to). 
2. Thread the string through the straw. 
3. Tie the loose end of the string to another chair (or again, whatever other objects you would like). 
4. Move the chairs apart until the string is straight and taut.  
5. Place two pieces of tape on the straw. 
6. Blow up a balloon and secure the balloon to the straw using the two pieces of tape. Make sure you hold the end of the balloon so air can’t escape. 

So simple right? In minutes you get everything all set up, and all you need to do now is let go of the balloon and watch it fly across the room (or however long your string is)! 

I didn’t anticipate just how thrilled my kids got when they saw the balloon rocket across the string. They screamed and shouted and sprinted to get the balloon so that we could do it again. I could see the excitement in their eyes and of course, I was happy to repeat the experiment again… and again…and again.  

I did try taping the balloon in different ways to see if I can prevent the balloon from flying off the straw when it reaches the end, but short of using duct tape, my balloon always flew off. That said, the kids thought the balloon flying off was hilarious, so oh well!   That said, I didn’t like wasting the tape that was holding the balloon to the straw. When I initially did this balloon rocket experiment, the tape would get stuck onto itself after the balloon flew off. The only way to attach the balloon to the straw again was to rip off the original tape and use new ones. 

So instead of securing the balloon by taping OVER the straw, I made a loop with the tape (essentially creating double-sided tape) and tape one side to the straw and the other to the balloon. It’s not as strong of adhesion, but we got a handful of balloon blastoffs before the tape lost its adhesion ability. 

I know what you are thinking …are my kids too young for this? Let me tell you, my 2-year-old daughter enjoyed this balloon rocket experiment every bit as much as my 4-year-old son. And even though neither of them really understands any physics concepts, doing STEM projects such as this helps them develop theories about how the world works. Therefore, try these different options to really blow your kid’s mind: 

• Differently sized balloons. 
• Blow up the same balloon with different amounts of air. 
• Lifting one side so that the balloon must travel on an incline up the rope. 
• Bring the chairs slightly closer together so that the rope is not taut. 

Trust me, my son was plenty interested when we tried all these different options and kept asking his favorite question, “WHY?” Why did the big balloon travel farther? Why did the balloon have trouble climbing up the rope?  Have multiple kids? Make two sets of these and have the balloons race!Talk about some safe and educational sibling rivalry!