Explore: Propulsion Pop!

When you fill a balloon and let it go, you are applying Newton’s Third Law.  The air in the balloon pushed backwards.  The equal and opposite reaction pushes the balloon forwards.  Basically, that is how propulsion works.

This concept has been applied to put rockets into space. Wow! That’s simple! Of course, launching a rocket requires considering many more factors than launching a balloon.  Much trial and error was needed to design the system to allow people to explore space safely and reliably.

This next activity will test your skills as a rocket designer. Use what you know about the forces of flight and propulsion to design and test your own rocket.

  Video

Before you begin designing your rocket, watch these videos to get some ideas about how it can work:

  Notebook: What fuel provides the best propulsion for a rocket?

  1. Click here to download this activity. 
  2. Complete the activity and save to your Flight Notebook.        


  Check Your Answers

Answers will vary greatly because this has many variables such as the temperature of your water, how tightly your canister is capped, how heavy your rocket is, etc. However, most people get reasonable results using about half a canister of water with about a quarter tablet of Alka-Seltzer. Leaving some room in the canister for the gas pressure to build up produces better results than filling it all the way with water.