How to Build a Water Rocket

Ever dreamt of flying your own rocket! Then let us learn how to make one. And don’t worry, this one works on water. So don’t be afraid of the explosives. The principle used here is very simple. If air is pressurized then it can be used to propel any object upwards. If you use water in addition to air then you can easily reach higher than trees. Make your own water rocket using some inexpensive stuff.

Tools required:

  • Hacksaw
  • Pliers
  • Drill
  • Scissors

Materials needed:

  • PVC pipe( 10 ft. long and diameter about 0.5 inch)
  • PVC end caps -2
  • PVC – tee ( diameter 0.5 inch)
  • PVC pipe cleaner, cement
  • Duct tape
  • Clamp, Soda bottles ( 2 liter)
  • String (cotton or regular twine), candles, plastic cable ties
  • Tire valve
  • Scrap PVC pipe (1.5 or 2 inch diameter)

The rocket is propelled using the force of pressurized air and so all the parts should be sealed perfectly to maintain the optimum pressure. PVC pipes are used since they are quite strong and mostly leak proof. Make sure that the pipe is cleaned well before attaching them. Steps involved in the making of water rocket:

  1. Cut the PVC pipe into three pieces of lengths: 2 inch. , 18 inch. , and 78 inch; with the hacksaw.
  2. Fit a 0.5 inch bit to the drill and drill a hole in one of the PVC caps. Make sure the drill is held straight and use pliers to hold the cap steady.
  3. Take a tire valve and remove its cap. Now slide this valve through the hole of the end cap. Put the valve cap back to the valve. Make sure that the valve is firmly fixed in the cap.
  4. Place the connectors and pipe section that we made earlier, in proper order, in which they are to be assembled. The proper order is: first the solid end cap, then 18-inch pipe, then the longest section (78 inch) and connecting the leg of tee by the 2-inch pipe.

Now clean the pipes using the PVC pipe cleaner, both from inside and outside. Then join the pipes one by one using the PVC pipe cement. Hold the parts for a while to allow the cement to set.

Take care that you work in an open area while applying the cement.

  1. Taking 11 inches from the long end, mark the pipe. Heat the pipe at the mark till it is softened. Then make a slight bulge at the soft area by pushing it inward. Let the pipe cool and hold it straight until it cools. This creates a seal between soda bottle and the pipe.
  2. Tape nine parallel cable ties facing in same direction. Tape them properly on both sides.
  3. Now take a soda bottle and slide it through the open end and make sure it is sealed against the bulge. And fix the cable ties around the neck of the bottle.
  4. Cut a soda bottle from top and bottom, then flatten the sections and cut holes from both sections each measuring 1.25 inches. This will be the spring to hold trigger before launch. Then make a small hole in a scrap 1.5 inch PVC pipe. Tie a piece of string through the hole; the pipe will be our trigger.
  5. Now remove from pipe and slide the spring into pipe, against the pipe clamp, over the cable ties. Then put the PVC scrap over pipe and cable ties. Then pull out a string from holes of the plastic spring and tape other end of string to the pipe using duct tape.
  6. Then test the trigger by pulling the string. The trigger drops opening up the cable ties. Now, fill a soda bottle one-third with water and slide this onto the pipe end. Pull the string from the trigger so that bottle is set against the bulge and cable ties catch bottle’s lip. Release string and let trigger slide back to hold bottle in place.
  7. Lastly pump about 70 psi into the launcher by attaching a bicycle pump to valve.
  8. Point the launcher straight up, pull the string to launch the rocket.

NOTE: Adult supervision is necessary during the launch.

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