Build a Two-Stage Balloon Rocket

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Here's how.

Active Time

45 minutes to 1 hour

Total Project Time

45 minutes to 1 hour

Key Concepts

Energy, Newton’s third law of motion, spaceflight

Two long and skinny balloons are taped to straws and each other to form a two-stage balloon rocket

Introduction

If you have ever watched a rocket launch on TV, you might have noticed that rockets have multiple stages. Some parts of the rocket fall off and burn up in the atmosphere whereas the rest of the rocket keeps going. Why does this happen? Try this activity to find out and build your own two-stage rocket using balloons!

Credits

Sabine De Brabandere, PhD, Science Buddies

This activity is not appropriate for use as a science fair project. Good science fair projects have a stronger focus on controlling variables, taking accurate measurements, and analyzing data. To find a science fair project that is just right for you, browse our library of over 1,200 Science Fair Project Ideas or use the Topic Selection Wizard to get a personalized project recommendation.

Next: Materials

Materials

Two modeling balloons (These are the long, skinny kind used to make balloon animals, not the round kind.)
Two straws
Two large binder clips
Paper towel tube
Fishing line or string (A fishing line will generally work better because it has lower friction.)
Scissors
Clear or masking tape
One other person to help set up the rocket
Balloon pump, to make it easier to inflate the balloon (optional)
Two sturdy pieces of furniture across the room from each other (to which you can tie your fishing line or string)—The farther, the better!
Open space where you can set up the activity