Building and Launching a Model Rocket — Children build and decorate a model rocket using oak-tag poster board for the rocket body, nose cone, and fins. A 35-mm film canister, which will later be filled with a fuel mixture of baking soda and vinegar, is the rocket's engine. The children launch their rockets.
What's the Point?
A force must be exerted for a rocket to lift off from a launch pad.
The motion of the rocket is equal to, and in the opposite direction of, the thrust of the rocket's engine.
The greater the mass of the rocket, the greater the amount of thrust needed to launch the rocket.
Given a fixed amount of thrust, the distance a rocket travels decreases at its mass increases.
For each child or small group of children:
Oak-tag poster board (8 × 10 sheets)
Plastic 35-mm film canisters (Fuji Film© canisters are recommended)
Plastic picnic spoons (or a set of measuring spoons)
Optional: Alka-Seltzer and water (can be substituted for baking soda and vinegar)
For the facilitator:
1. Have the children gather all the items needed to construct their model rockets.
Children will need oak-tag poster board with the rocket cut-out pattern, 35-mm film canister, scissors, tape, and rocket-decorating supplies.
Fuji Film© canisters are recommended because their caps attach into the inside of the canister, which enables them to pop off cleanly once sufficient pressure builds up inside the canister to blow the lid off. Film canisters with lids that grip the outside of the canister do not pop off in a consistent manner.
Use a copy machine to copy the rocket cut-out pattern onto poster boards in preparation for this activity.
2. Explain that they will need to cut out the rocket parts from the cut out pattern on the oak-tag poster board as these parts are scaled to fit onto the 35 mm film canister.
Show the children a sample model rocket that you have constructed.
Have them decorate the parts of their rocket before assembly.
5. Roll the nose cone section into a cone shape that is the same diameter as the rocket body. Tape along the seam to hold the nose cone together. Next tape the nose cone to the top of the rocket body.
Launching a Model Rocket
6. Choose a launch platform that is outside or in an uncarpeted room with a high ceiling at least 20 feet tall. All children other than the child launching his/her rocket should stand at least 10 feet back from the launch area. Make sure that the child launching his/her rocket is wearing eye protection.
7. Turn the rocket upside down, take off the film canister lid, and place 1 teaspoon of vinegar into the film canister.
8. Measure ½ teaspoon of baking soda.
9. Pour the baking soda into the film canister. Quickly snap on the film canister lid and quickly place the rocket rightside up onto the launch platform. Step back from the launch platform.
These steps need to be completed very quickly as it only takes 3–5 seconds for sufficient gas pressure to develop to blow the lid off the film canister.
Note: Alka-Seltzer and water can be substituted for the baking soda and vinegar in this experiment. Place ½ of an Alka-Seltzer tablet into the canister, then fill the container ½ to ¾ full of water. Snap the lid closed and follow the activity procedure.
To add a sense of realism, have the children count down backward from 10.
Have the children judge the relative height of each launch by referencing the maximum height to a specific point on a background object.
10. After each child has launched his/her rocket, help the children think about this activity by discussing the following questions.
Why did some rockets fly higher than others? How is your rocket similar to, and different from, a real rocket? What caused the rockets to move? What could be changed to make the rockets fly higher? What would happen to the rocket's flight if you removed the nose cone and/or the fins? What would happen if two similar rocket engines, facing directly opposite each other, were ignited at exactly the same time?
February 4, 2010