• In this how-to video, TOH host Kevin O'Connor and middle school teacher Slater Harrison show adults and kids how to make a water rocket from simple PVC plumbing pipe and some plastic soda bottles.

    Age Range: 7 and up

    Steps:1. Using the hacksaw, cut three lengths of ½-inch PVC pipe: 2 inches, 18 inches, and 78 inches.
    2. Using the drill/driver fitted with a ½-inch bit, make a hole in the top of one of the PVC end caps.
    3. Remove the small cap from the tire valve and set it aside. Slide the valve through the hole in the PVC end cap so that it sticks out the top. Screw the valve cap back on. Grab the end of the valve with pliers and pull it until it's firmly seated in the PVC end cap.
    4. Line up the pipe sections and connectors in the order in which they will be assembled: solid end cap, 18-inch piece, tee, 78-inch piece, and the 2-inch piece connected to the leg of the tee. Using PVC pipe cleaner, clean the outside of the pipe and the inside of the fitting. Glue the connections together with PVC pipe cement.
    5. Mark the pipe assembly 11 inches from the long open end. Using the flame of a birthday candle, heat the pipe evenly at this mark until it becomes soft. Then push the pipe inward to create a slight bulge. Hold the pipe straight until it has cooled and the bulge is no longer soft. This bulge will create a seal between the pipe and the soda bottle.
    6. Using duct tape, tape nine cable ties together so that they all face in the same direction. Tape over both sides so that no adhesive is showing. Slide a soda bottle over the end of the pipe and seat it against the bulge. Wrap the cable ties around the pipe so that the head of each tie faces inward and catches the lip of the bottle. Secure the cable ties in this position by tightening the hose clamp around the duct tape.
    7. Cut the top and bottom off a 2-liter soda bottle. Flatten the bottle section without creasing it and cut a 1¼-inch hole through both sides. This spring will hold the trigger in position until you're ready to launch. Drill a small hole in the side of a short scrap of 1½-inch PVC pipe. Thread the end of a 4-foot piece of string through the hole and tie a knot on it to keep it from coming out. This pipe is the trigger. Remove the bottle from the end of the pipe. Slide the plastic spring onto the pipe, over the cable ties, and up against the pipe clamp. Then slide the 1½-inch PVC scrap over the pipe and cable ties. Thread the string through the holes in the plastic spring. Tape the other end of the string securely to the pipe with duct tape. Test by pulling on the string. The PVC trigger should drop, allowing the cable ties to open up. When you let go of the string, the spring should push the trigger up and over the cable tie ends.
    8. Fill a 2-liter bottle about one-third full of water and slide it onto the end of the pipe. Pull the string on the trigger down so that the bottle can seat against the bulge and the cable ties can catch the bottle's lip. Release the string and let the trigger slide back over the cable ties to hold the bottle in place.
    9. Attach a bicycle pump to the valve coming out of the tee. Pump no more than 70 psi into the launcher.
    10. Make sure the launcher is pointed straight up and that there is adult supervision for every launch. Count down, pull the string, and blast off!

    The plans for this rocket were developed by middle school teacher Slater Harrison. To see his detailed assembly instructions, click here
    • Difficulty: Easy
      Sawing the pipe and making tight seals require a little muscle, but nothing an older kid can’t handle.
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      Tools List

      • hacksaw
        hacksaw
      • drill
        drill/driver fitted with a ½-inch bit
      • adjustable pliers
        pliers
      • utility scissors
        scissors

      Shopping List

      1. 10-foot length of ½-inch PVC pipe
      2. ½-inch PVC tee
      3. two ½-inch PVC end caps
      4. 2-inch-long scrap of 1½-inch PVC pipe
      5. PVC pipe cleaner
      6. PVC pipe cement
      7. replacement valve for a tubeless tire
      8. plastic cable ties, aka zip ties
      9. birthday candle
      10. duct tape
      11. clamp for 1½-inch hose
      12. two 2-liter soda bottles
      13. string (regular twine or cotton string is fine)