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How Do Rockets Fly?

Watch Newton's third law of Motion in Action

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How Do Rockets Fly? - Controlled Propulsion Experiment - Balloon - How Do Rockets Fly?

How Do Rockets Fly? - Controlled Propulsion Experiment - Balloon

NASA
Equipment Needed
  • Drinking Straw
  • String
  • Long Balloon
  • Transparent Tape
  • Clothespin
  1. Thread the string through the straw.
  2. Tie the string between two tree.
  3. Blow up your balloon. Seal the mouth of the baloon with the clothespin. (Note: It may help to fold the neck of the baloon once or twice before applying the clothespin.)
  4. Tape the baloon lengthwise along the straw.
  5. Remove the clothespin and release your balloon.
As you watch your balloon rocket fly along the string, you are observing Newton's Third Law of Motion; "For every action, there is an equal and opposite reaction." The air escaping the ballon is the action and the balloon traveling along the tring is the reaction.

Try some variations

  • Raise the opposite end of the string. What affect does this have on your balloon's flight? Why?
  • Add a second straw and ballon to the string, facing the opposite direction. Tape an additional short length of string (about 2 feet) between the balloons. Do the two balloon rockets move in one direction or the other? Why?

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