Water Rocket Mission Your mission: To successfully launch a rocket with a payload and retrieve the payload without injury

Possible Materials 2-liter soft drink bottle food trays Poster board Cardboard Masking 4 ounces of clay Safety goggles Plastic grocery sacks or thin fabric scraps String Sandpaper or emery boards Your payload is a raw egg

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.

KWL This is a team effort, so you must first figure out what your team knows already to make a launch Use the Butcher paper to list all the things you think you know about rockets—what makes them launch, what physics do you already know to help. Do your partners agree? What are you unsure of that might help you find out?

Things to think about as you design 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.

Plan your construction Do you need some way to hold your rocket as you construct it? How can you add fins and nose cone? What size should they be? How much ballast should you have in your nosecone? What can you use as a recovery system? (parachute?)

Criteria for experimental design to build a better rocket Written Design with dimensions and drawings Must have a parachute or retrieval system Must have a way to carry your payload

Before launch you must test your rocket When the rockets have been completed, you will qualify your rockets for flight by conducting string tests. Using several feet of string, tie the rocket around the middle so that it balances. Because of the nose cone weight, the balance point will be towards the nose. When the rocket hangs level, a small piece of tape should be temporarily fixed to the string and bottle to keep the string from slipping. The rocket is then twirled in a circle. If the rocket tumbles while circling, it is not stable and needs more nose cone weight, bigger fins, or a combination of both. If the rocket circles with the nose always pointed forward, it is stable and ready for flight.

Design You must have a completed design by the end of today. Your design must be written down with a list of materials, a schematic drawing of your rocket and a written plan of sizes and dimensions. If you want you can pick up supplies today and put them in a bag and label your group and period number. You are welcome to add to the supplies with material from home but realize you will need to have them here next class period.

We will Test flight on Wed. for A days and Thursday for B days If your payload was unsuccessful—you may change one variable and one variable only to make your second attempt successful. If your payload was successfully retrieved change one variable to see if you can get your rocket to go further.

Final Paper-one per group Design must be written down with a list of materials, a schematic drawing of your rocket and a written plan of sizes and dimensions Explanation of variable and why you chose it. Hypothesis (what you thought would happen with the variable and why) Results and Data. What happened? Analysis of data. Why did it happen? Conclusion: Explanation of the bigger picture. What did your investigation explain about rocketry and what concepts might we study in physics that would relate to rockets.