We love science activities (like this awesome DIY pulley!)! I read about how to build a balloon rocket in a book that happened to be sitting on a table in a doctor's office waiting room. True story. 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.
Pro Tip: Check out Steve Spangler Science's Amazing Monthly Science Kit for Kids. I am really impressed with it.
How to Build a Balloon Rocket
The best part about this activity is the 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 for a Balloon Rocket
- Sturdy Straw
Approach to Making a Balloon Rocket
- Cut a piece of string long enough to attach across a room or large doorway
- Use a 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 taut.
- 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 a Balloon Rocket
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 imagine 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