Lab: Bottle Rockets

Purpose: To create a rocket that will fly straight and will stay in the air for as long as possible.

Background Information: Launching something as large as the space shuttle is a complex project. But scientists can send this huge vehicle into orbit partly because they understand the natural laws that describe how objects move. Scientists discovered these laws years ago. Yet the laws are still fundamental to every rocket launch, even the bottle rocket that you will launch in this lab. The same law that states how hitting a tennis ball makes it go faster also tells how rockets are launched.

Materials:  Two empty 2-liter bottles  Manila folders or cardboard  Duct tape  String  Garbage bag (tall kitchen bag) If your group needs materials, you must notify instructor 24 hours in advance to allow instructor to obtain necessary materials for your group.

Rules:  Groups are not to exceed 3 people.  Each group will use two standard 2-liter soda bottles to build their rocket. No commercially finished or model products may be used.  One of the 2-liter bottles must be used as the pressurized body. There may not be any cuts or holes in the 2-liter bottle, and no metal parts of any kind will be allowed on the pressurized body. Do not use hot water or sharp instruments on the pressurized body.  When cleaning your bottle, do not use sharp instruments of any kind.  The mass of the empty rocket assembly may not exceed 300 grams.  All energy put into the rocket must originate from the water/air pressure combination.  All rockets will be launched at a pressure not to exceed 60 pounds per square inch. Once the rocket is pressurized, no student can touch or approach the rocket!!!  All students will be required to wear safety goggles at all times!!!  Prior to launch, each rocket must pass a safety inspection and have the mass measurement verified by teacher.  Though various rocket components may separate during the flight, all must remain linked together with a maximum distance not to exceed three (3) meters. If a nose cone is used, it can separate, but should remain attached to the rocket body. If any part of the rocket becomes unattached during flight, the rocket time will be used from when the first part of the rocket hits the ground.  Students are not allowed to use hot glue or super glue in constructing their rockets. Cold glue is acceptable. Sanding is not allowed on the pressurized body.  The use of duct tape is highly recommended.  All building must be done during designated class time. Part I: Constructing Your Bottle Rocket A) Below is a diagram of how your bottle rocket should be put together:

B) Nose Cone a. To construct the nose cone for you rocket use a piece of poster board or a manila folder. b. Draw a circle with a radius of approximately six inches, and cut it out. c. Cut one slit from the outer edge of the circle to the center. d. Fold the poster board until it creates a cone that fits on top of you rocket, e. Attach the nose cone to the sleeve use a piece of string.

C) Fins a. Create 3 or 4 fins to put on the pressurized bottle. b. Fins can be created from poster board, manila folders, or cardboard. c. Fins need to be strong, and not flexible. d. Fasten the fins to your rocket using tape or glue. The fins need to be spaced equally apart.

D) Parachute a. Take a large garbage bag and lay it out flat. b. Cut a large circle out of the bag. c. Put 16 pieces of masking tape around the edges of the bag, evenly spaced. d. Punch one hole through each piece of tape. Use a reinforcement tab around each hole. e. Attach sixteen 32-inch long strings to the bag, evenly spaced. i. Put 4 strings on your parachute. Tie these four strings together at the base of the strings. ii. Repeat 3 more times. (You should have 4 groups of 4 strings) iii. Use duct tape to tape the ends of the strings to your pressurized bottle. f. Fold the parachute and strings so that it makes a “z” shape.

Part II: Launching the Bottle Rocket Safety:  Students are required to wear safety goggles at all times.  Students are not allowed to approach or to touch the rocket once it is pressurized.  Students are expected to stay with the rest of the class and to be aware of rockets that are launched.

Participation:  Each group member is required to contribute equally.

Procedure: 1. Get your rocket ready to launch. 2. Fill your rocket half full (1L) of water. 3. Put the cap on the end of the bottle and take to waiting zone. 4. When called upon, place your rocket on the launch pad. a. Launching: a.i. Max amount of water is 1 L of water. Additional water will be taken out. a.ii. Pressure of lunch may not exceed 60 pounds of pressure on bike pump. Groups may go less if so desired. 5. Two of your group members will have a stopwatch. a.Member 1 and 3: Start the stopwatch when the rocket is launched, stop timing when the parachute deploys. Record the time in the appropriate column in your data table. This will be used to determine if there is a tie on total time in air. b. Member 2 and 4: Start the stopwatch when the rocket is launched, stopped timing when the rocket hits the ground. Record this time in the appropriate column in your data table. 6. Repeat steps 1-6 for a total of two times.