Alka-Seltzer® Rockets
Purpose
To design a paper rocket propelled
by Alka-Seltzer® and water to demonstrate Newton's third law of motion.
For other interesting experiments with Alka-Seltzer® see Student Experiments.
Background
The paper rocket in this activity
is propelled according to the principle stated in Isaac Newton's
third law of motion: "For every action there is an opposite and
equal reaction." Gas pressure builds inside the film canister
due to the mixing of Alka-Seltzer® and water. This action continues
until enough pressure builds to blow apart the canister from its lid.
The reaction is the launch of the rocket.
Materials
Seltzer Rocket Patterns
To print to scale:
- Save the image to your disk (right click "Save Picture As").
- Open the image in a good image editor.
- Set the print options so that the image is 7.6 x 10.0 inches.
Color Patterns to choose from:
  
Black and white for you to color:
Other Materials
Empty film canister with lid that snaps
inside; markers, crayons, or colored pencils; tape; glue; scissors;
Alka-Seltzer® tablets; water; metric tape measure or meter sticks;
straw; (Optional launch pad: wood block, coat hanger or other stiff wire)
Preparation
Review and prepare materials. It is
most important to use film canisters with lids that snap inside. Do
not use lids that close around the outside of the canister.
Construction
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1. Cut the fins out. Cut the nose
cone and body out as one piece. |
2. Tape the body onto the film
canister, roll the paper around the side, and tape the end down. The
lid end of the film canister goes down. |
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3. Roll the nose cone around in the
shape of a cone and tape it together. Straighten the nose cone point
to the center of the rocket and tape it to the sides. |
4. Fold the fins so that the
colored side is out. Tape or glue the fin halves together to form a
complete circle. |
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5. Slide the fins over the body and
tape in place. |
6. Cut a 1 inch piece of straw and
tape it to the body. |
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Launch Time
This is an outdoor activity. If
gusty winds are a problem, then place a quarter in the canister to
keep the rocket from falling over. Launching near a wall where a
metric tape has been hung or where meter sticks have been stacked may
make it easier to judge how high the rocket goes. You may want to
wear safety glasses during this experiment as a general safety
precaution. Everyone should stand away from loaded rockets when they
are on the launch pad. It may take 15 to 20 seconds to build up
enought pressure to launch, so a loaded rocket should not be
approached prematurely. These rockets can shoot 5 meters or more into
the air. No sharp objects should be placed on top of the nose cone or
elsewhere on the rocket.
Make a launch pad with a block of
wood and a straight piece of wire. Drill a hole for the wire and
insert the wire straight up to guide the rocket at lift off.
Wrap-up
One way to record the results of
different "fuel" mixtures is to make a simple graph of
height vs. amount of water. Such a graph gives a clear, visual record
of the observations and can be used as evidence to support interpretations.
Design and launch other rockets
powered by two, three or more film canisters. Design a two-stage rocket.
NASA's web page on soda bottle
rockets: nasa_321pop.htm
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