Easy Science Activity with Balloons – How to Build a Balloon Rocket

Science activities for kids is a hot topic in my home! Rocket ships are up there big time! So, I was excited when I read about this science activity for preschoolers in a book recently and I had to try it and, of course, share it with you. In this post, learn a super cool science activity with balloons: how to build a balloon rocket & impress your kids. 

Science Activity with Balloons

Great science activities come from all necks of the woods, just have to keep your eyes open. I honestly don't remember the exact title of this activity. So I will name it what my sons call it, a Balloon Rocket.

How to Do this Preschool Activity

The best part of this science project with balloons is simplicity. The materials are easy to pull together and don't cost much. Plus kids learn about science and have loads of fun doing it.

Materials Needed 

• Scissors
• String
• Tape
• Sturdy Straw
• Balloon

Approach 

• Cut a piece of string long enough to attach across a room or large doorway
• Use strong tape to secure one end of the string onto one wall (in our case we used a window sill)
• Thread the other end of the string through the straw
• Tape the other end of the string to the opposite wall or window sill. You want it to be tight.
• Cut two pieces of tape to place over the straw
• Blow up the balloon and secure the balloon with the two pieces of tape on the underside of the straw
• Let go and observe!

Science Behind this Activity

When you let go of the balloon, the air rushes out thrusting the balloon rocket in a forward motion. Thrust is an actual science term defined as the pushing force created by energy. In this case, the thrust comes from the air coming out from the balloon. That air is energy pushing the balloon forward. Rockets in the real world create thrust by the force of burning rocket fuel blasting from the engine in a downward motion forcing the rocket up.

What to Do Next?

• Get creative making zip lines for Lego mini figures, or allow your child's imagination to take over
• Ask your child how the balloon moves forward and define “thrust”
• Compare the balloon rocket to a real rocket. The air from the balloon rocket is equivalent to what from a real rocket?
• Use different sizes of balloons, different types, and lengths of straws, different length of travel, different types of string: how do these changes impact the balloon rocket? Hypothesize and then test.

• Change the angle of the string
• Measure the differences, create a graph, compare and contrast these differences and determine what impacts your balloon rocket most and least
• Buy the book 101 Great Science Experiments for loads more science fun

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