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How to Make Water Rockets Go Faster

Water rockets are constructed from plastic soda or water bottles. The bottle is filled 1/3 or 1/4 with water and stoppered with a rubber stopper. A small hole in the stopper accommodates the needle from a bicycle pump. The young scientist will stand the bottle up and pump until the pressure inside the bottle forces the stopper out and the bottle sails up into the air. Using the same principles of aerodynamics used in airplanes, there are a number of techniques you can use to make your bottle fly faster and higher.

Things You'll Need

5 sheets of poster board
3 oz. ball of clay
Tape
Scissors
Straw
1/4 inch metal rod

Instructions

- 1
  Make a nose cone for your rocket to make it more aerodynamic. Roll one piece of poster board into a cone shape and tape. The bottom of the cone must be the same size as the bottom of the bottle. Cut the bottom of the cone straight. Place the ball of clay in the nose of the none and tape in place. Tape the cone onto the bottle. Added weight will stabilize the rocket.
- 2
  Stabilize the rocket by adding fins. Energy lost by rolling will be used to power the rocket faster and higher. Cut four fins from the poster board and glue them to the sides of the rocket, near the bottle top. Experiment with fin size and shape to see which ones work best for your bottle shape.
- 3
  Create a launch pad to help your rocket go faster. Tape the straw to the side of the rocket. Press the 1/4 inch metal pipe into the ground at a 45 degree angle. Feed it through the straw and you are ready to launch.
- 4
  Ensure the bottle is sealed properly. If the rubber stopper is the wrong size or the hole for the pump needle is too big, valuable pressure will be lost. Choose the correct size stopper for your bottle and the correct drill bit for the size needle your bicycle pump uses. Pump quickly to ensure that the pressure build up inside the bottle is not lost through leaks.

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