OVERHEAD WATER ROCKET
Water Resources Activity
Facilitators: Dr. Jairo Hernandez (Assistant Professor, Civil Engineering Department), Guillermo
Najera (Mechanical Engineering undergraduate student)
(Source: google.com/images)
(Source: google.com/images)
The first rockets were invented around 1100 AD in China; these rockets were mainly
used as fireworks at first. Simple and creative innovations like a rocket take more than just
common sense, there is science and engineering behind the manipulations and developments
of such simple artifacts. In this day and age the incredible ingenuity of engineers and scientist
and the advanced technology at hand has led the way for rockets of extreme capabilities and
complexity to be developed.
Water can be a tremendous resource when it comes to generating energy and work.
The reason for this, is because water can become a force. This force carries linear momentum
when in motion. Linear momentum (p) is the product of the mass (m) and its velocity (v) and
can be stated as p = mv. This momentum can be conserved or it can be transferred. By the
other hand, pressure (P) is the equivalent of a force (F) being applied to an area (A) and
therefore stated as P=F/A When the linear momentum is transferred, it can be applied to other
mechanisms to use energy. In this experiment we will use the water's linear momentum in
conjunction with pressurized air. The pressurized air will expel the water to propel a rocket up
into the sky! Let's make water do some work for us!
Materials
2 Soft Drink bottles
1/2 inch PVC pipe – 10ft
Roll of Duct Tape
1 and 1/2 inch PVC pipe – 3in
Roll of electrical Tape
1/2 inch Internal Threaded
Adapter
Sand Paper
1/2 inch external Threaded
Adapter
Air Pump
1 roll of Teflon tape
Drill
Can of PVC pipe cement
Drill bits
Hose Clamp
1/2 inch PVC slip T
8 Plastic Zip ties
1/2 inch PVC end caps
Air Valve stem
Candle
Roll of twine
Procedures (see pictures on last page)
Gather necessary materials first. Construction can be separated in three activities: (1)
bottle seal, (2) trigger, and (3) piping and fittings, as follows.
Bottle seal
1. To begin cut 48 inches of ½inch PVC piping.
2. Insert the PVC piece from step one into a 2 liter bottle. Insert the PVC pipe enough for
the PVC to not touch the end of the bottle. With a Pencil mark the PVC where it is
aligned with the opening of the bottle. (image 1)
3. Using a candle heat the PVC at the line you marked in step 2. This will soften the plastic,
heat it until it is flexible enough to bend. (image 2)
4. Push the two ends of the PC towards the line marked. This will create a buldge. This will
act as the seal for the bottle. (image 3)
Trigger
5. Obtain 8 zip-ties and place them beside one another. Using about 2 inches of duct tape,
tape both sides of all 8 zip-ties at the bottom leaving the head of zip-ties free. (image 4)
6. Use a hose clamp to attach the zip ties to the 48in piece of PVC. Place the hose clamp
around the duct taped part of the zip-ties. Attach zip-ties close to the buldge and tighten
the clamp with a screwdriver. (image 5)
7. Get 2 inches of the 1½ PVC piping and drill a small hole at the bottom of the piece. Make
the hole big enough for the twine to fit through. Place around zip-ties. (image 6)
8. Cut the middle section of a 2 liter bottle (about 4in). You will have an open-ended
cylinder that will act as a spring. Cut a hole (1½ diameter) on opposite walls of the
cylinder exactly in the middle. (image 7)
9. Mount the spring in between the hose clamp and the bottom 1 ½ PVC section. (image 8)
Piping and Fittings
10. Cut an 18 inch piece of the ½ inch PVC pipe. Using PVC cement attach an end cap at one
of the ends. (image 9)
11. Cut a 2 inch piece of the ½ inch PVC pipe.
12. Cut a 30 inch piece of the ½ inch PVC pipe. Using PVC cement attach a ½ external
threaded adapter to one of the ends.
13. Using PVC cement attach the internal threaded adapter to the 48in piece of PVC from
(step 1)
14. Get another end cap and drill a hole on the end. The hole should be big enough for the
air valve stem to fit tight. (image 10)
15. Using the end cap from step 14 and with the air valve attached. Use The PVC cement to
glue the 2in piece of pipe from step 2 to the end cap. (image 11)
16. Obtain a ½ inch PVC slip T. Using the PVC cement attach the free ends of the 18 inch
pipe and the 30 inch pipe (from steps 10 and 12) to the two ends of the Slip T. (image
11)
17. Attach the 2 in PVC pipe with the air valve to the out-going end of the Slip T. (image 11)
18. When Launching screw the external adapter attached to the 30 inch pipe and screw it to
the internal adapter of the 48 inch pipe.
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References
siencetoymaker. (2013, April 16). How to Make an Overhead Water Rocket Launcher.mov
Video file. Retrieved from https://www.youtube.com/watch?v=xqLbnsylF-Q
Enos, Taylor, and Jamie Adams. Water Works! Ed. Jairo Hernandez. Boise: Boise State University, 2014.
Print. 08 June 2015.