Seltzer Rocket

How to Build and Launch an Alka-Seltzer Rocket

This project is a fun approach to leaning some basic physics. As a bonus, students take an interdisciplinary approach to creating a successful launch by using skills in art, engineering, physics and math.

Alka-Seltzer Rocket

Here is what you will need to complete this project

  • Film canisters with internal lipped lid like Fuji Film canisters (ask your local photo development/print store)
  • Colored construction paper or white injet paper
  • Scissors
  • Compass to draw circle for nose cone
  • Ruler or straight edge
  • Alka Seltzer tablets
  • Water
  • Thermometer (optional, if you want to test water temperature as a variable)
  • Stop watch (if you want to determine how much time it takes to pop the lid)
  • Clip board, paper, pencil to record results
  • Alka Seltzer Rocket Experiment Worksheets

    STEP 1.

    Decide how tall to make your rocket body and draw a rectangle onto a piece of colored construction paper. You can start with a rectangle the size of an index card and make different body sizes to see if body size affects launch height, etc. Cut out the rectangular body piece and wrap it around the film canister (which should be oriented so that the lid is facing downward). Use a small piece of scotch tape to secure the rectangular body piece to the canister. Use another small piece of tape to hold the body tube together.

    STEP 2.

    Select a piece of colored construction paper to create the nose cone and fins. For the nose cone, use a compass or trace around the outside of the base of a cylinder (such as a canned vegetable can). Cut out the circle and then cut out a segment so that the paper can be folded into a cone shape. Use a piece of tape to secure the cone. Place two small pieces of scotch tape inside the top of the body tube with a small part of the tape protruding above the top. Place the nose cone on top and secure the cone to the pieces of tape.

    For the fins, choose the size and shape you want for fins and, using a straight-edge, draw four equal shapes on your colored construction paper. Cut out fins and tape to body around the base.

    STEP 3.

    Now you are ready to launch your rocket.


    Using a sharp knife, slice a few Alka Seltzer tablets into four equal sections and place into a zip top baggie. Use a plastic water bottle with a lid to carry water needed for the fuel. NOTE: If you want to test how water temperature affects the launch, heat some water briefly and put in separate bottle. You will need a thermometer if you want to record the exact temperature.


    Assign someone to be the “data engineer” to read the stopwatch and record times and other data on clipboard. The other person will be the “field engineer” and will be responsible for fueling and retrieving the rocket. All team members should wear safety goggles during the launches.

    To add fuel, first turn the rocket upside-down and remove the canister lid. Add a little water (approx. 1/2 canister) and quickly add a quarter of an Alka-Seltzer tablet to the water. Tell the data engineer to start the launch clock (stop watch). Replace the lid and set the rocket on the launch pad. Quickly move back several feet.


    Experiment with different body sizes, construction materials and cone and fin sizes and shapes

    Add a payload (plastic army men?) and record what happens

    Experiement with different fuel mixtures (add more or less Alka-Seltzer and/or water) and record your results


    Diagram of how to construct rocket

    Nice Design template

    YouTube video of our rocket launches

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