Film can rocket

A rocket can be made with a film can.

The best film cans to use are the white ones with thick tops, the worst ones are the black film cans which often leak gas.

To Do and Notice

Put water into the film can until it is 1/4 full.

Put baking powder into the depression that is inside the lid.

Fill the lid with baking powder and then put water into the film can.


Put the lid on the film can, place it on the ground and step back. After ten seconds there will be a "pop" and the film can lid will be launched into the air.

Put the lid on the can and step back.

What's Going On?

Baking powder contains a dry tartaric acid powder in addition to bicarbonate of soda. When wet by water the tartaric acid dissolves and reacts with the bicarbonate releasing carbon dioxide gas. The pressure builds inside the can. When the pressure is great enough the lid of the film can is blasted into the air.

Going Further

What happens if you put the lid on the floor and the film can upright?

What happens when you put the film can on its side?

Try various amounts of water, which yields the greatest height?

You can also use vinegar and baking soda, however the reaction proceeds so rapidly that you may not have time to escape before the lid blasts off.

Try warm water and cold water.