• 1 balloon
  • 1 long piece of kite string (about 10-15 feet long)
  • 1 plastic straw
  • tape

  1. Tie one end of the string to a chair, door knob, or other support.
  2. Put the other end of the string through the straw.
  3. Pull the string tight and tie it to another support in the room.
  4. Blow up the balloon (but don't tie it.) Pinch the end of the balloon and tape the balloon to the straw as shown above. You're ready for launch.
  5. Let go and watch the rocket fly!

So how does it work? It's all about the air...and thrust. As the air rushes out of the balloon, it creates a forward motion called THRUST. Thrust is a pushing force created by energy. In the balloon experiment, our thrust comes from the energy of the balloon forcing the air out. Different sizes and shapes of balloon will create more or less thrust. In a real rocket, thrust is created by the force of burning rocket fuel as it blasts from the rockets engine - as the engines blast down, the rocket goes up!

Things to ponder…
  • Does the shape of the balloon affect how far (or fast) the rocket travels?
  • Does the length of the straw affect how far (or fast) the rocket travels?

  • Does the type of string affect how far (or fast) the rocket travels? (try fishing line, nylon string, cotton string, etc.)

  • Does the angle of the string affect how far (or fast) the rocket travels?
…try changing a material and see if you get different results…

  1. Was this activity a demonstration of balanced or unbalanced forces?
  1. What forces were acting on the balloon rocket?
  1. Why did the balloon rocket move forward?
  1. This lab is an example of Newton’s 3rd Law of Motion. This law states that for every action, there is an equal and opposite reaction. What force in the balloon rocket was the “action” force and what was the “reaction” force?

I. Types of Balloon Rockets:
1. Tracked balloon rocket: This rocket is guided to its target by fishing line.
2. Self-guided balloon rocket: This rocket has structures attached to the balloon thatcontrol its flight.
3. Multi-stage balloon rocket: This rocket uses 2 balloons. The 2nd balloon does not fire until the first one is nearly deflated.
I. The First Challenge
1. Choose a type of balloon rocket to build. Higher number is more challenging &will receive more points for success.
  • Practice & modify your design to make a better rocket. Your goal is for yourrocket to reach a target. You may change rocket types if you wish.
  • Sketch yourfinal design below.
II. The Second Challenge
1. How can you determine how fast your rocket flew? Was it the fastest in the class? Speed = distance / time.
III. The Third Challenge
1. How large a payload of paper clips can be carried to the light fixture?
  • Devise a way to attach paper clips to your rocket.
  • Run your experiment & record the maximum payload below:
IV The Fourth Challenge-The Conclusion Questions
  1. Sketch your rocket in flight. Show all the forces acting on it using arrows andlabeling the arrows.