Excerpted from the Water Rocket Construction activity of NASA's Rocket Educator Guide. Working in teams, students construct a simple bottle rocket from two-liter soft drink bottles and other materials. The rocket is powered by air pressure and water.
For example, Seminole SECME Hawk TeamObjective Student teams will construct water rockets and successfully launch them.
Success!Description Using 2 liter plastic soft drink bottles, cardboard or Styrofoam food trays, tape, and glue, small teams of students design and construct rockets. A simple assembly stand assists them in gluing fins on their rockets, and a nose cone is mounted on the top. The rocket is launched with a special launcher.
Gardner
Moore
Narcisse and Gardner
Dosch and Bartels
Pham and Masters
ZawackisProcedure
1. Set up a supply station with materials such as Styrofoam food trays, posterboard, tape, sandpaper, and art supplies.
2. Divide students into teams for constructing rockets. Discuss construction techniques for their rockets. Give each team an assembly stand and a 2-liter soft drink bottle. Require teams to keep track of the materials they used.
3. Describe how fins can be smoothed with sandpaper to slice through the air with little drag.
4. Review launch procedures with the teams. Conduct an inspection before the launch to ensure that rocket fins and nosecone are securely attached. 
Inspect each team’s rocket for the construction skill employed.
5. Set up a tracking station for measuring the altitudes achieved by the rockets. Follow all safety procedures and instructions when launching the team rockets.
Background
A water rocket is a chamber, usually a 2-liter soft drink bottle, partially filled with water. Air is forced inside with a pump. When the rocket is released, the pressurized air forces water out the nozzle (pour spout). The bottle launches itself in the opposite direction. The bottle usually has a nose cone for streamlining and fins for stability. Water rockets are easily capable of 100-meter-high flights, but advanced hobbyists have combined bottles and staged bottles for flights over 300 meters high.
Water bottle rockets are ideal for teaching Newton’s laws of motion. The launch of the rocket easily demonstrates Newton’s third law. Students can see the water shooting out of the nozzle (action) and see the rocket streak into the sky (reaction). Students can also experiment with different pressure levels inside the chamber and different amounts of water. The rocket will not fly very high if it is filled only with air. The air will quickly rush out during the launch, but its mass is very low. Consequently, the thrust produced is also low (Newton’s second law). By placing water in the bottle, the air has to force the water out first before it can leave the bottle. The water increases the mass expelled by the rocket, thereby increasing the thrust.
Like all rockets, the flight performance of water bottle rockets is strongly influenced by the rocket’s design and the care taken in its construction. Beveling the leading and trailing edges of fins allows them to slice through the air more cleanly. Straight-mounted fins produce little friction or drag with the air. A small amount of ballast weight inside the nose cone helps balance the rocket. This moves the center of mass of the rocket forward while still leaving a large fin surface area at the rear.
Bartels and Dosch prelaunchBartels and Dosch water bottle rocket launch
Masters and Pham prelaunch
Masters and Pham water bottle rocket launch
