Build a Film Canister Rocket

+Requires adult supervision+

Your Materials For This Experiment:

  • One empty 35 mm plastic film canister and lid.
  • One fizzing antacid tablet (such as Alka-Seltzer - Get this from your parents)
  • Water
  • Safety goggles

Now Follow These Steps:

Put on those safety goggles and head outside

Break the antacid tablet in half.

Remove the lid from the film canister and put a teaspoon (5 ml) of water into the canister

*Do the next 2 steps quickly

Drop the tablet half into the canister and snap the cap onto the canister (make sure that it snaps on tightly.)

Quickly put the canister on the ground CAP SIDE DOWN and STEP BACK at least 2 meters

About 10 seconds later, you will hear a POP! and the film canister will launch into the air!

*Caution: If it does not launch, wait at least 30 second before examining the canister. Usually the cap is not on tight enough and the build up of gas leaked out.

Here's what's happening?

There's nothing like a little rocket science to add some excitement to the day. When you add the water it starts to dissolve the alka-seltzer tablet. This creates a gas called carbon dioxide. As the carbon dioxide is being released, it creates pressure inside the film canister. The more gas that is made, the more pressure builds up until the cap it blasted down and the rocket is blasted up. This system of thrust is how a real rocket works whether it is in outer space or here in the earth's atmosphere. Of course, real rockets use rocket fuel. 

Courtesy of