What you need:
- sodium bicarbonate (baking soda)
- mixing cup and teaspoon
- film canister (they aren’t easy to find any more – ask for some used ones from your local camera store)
What to do:
- Place one teaspoon of sodium bicarbonate in the cup. Add a few drops of water and mix to form a thick paste.
- Put some paste inside the lid of the lm canister, packing the paste in tightly, away from the rim.
- Pour a small amount of vinegar into the lm canister so it is about one-third full.
- Carry the lid and canister separately to the launch pad (outdoors is best as this experiment can be messy).
- The next part has to be done carefully and quickly: Hold the canister in one hand away from your body and use your other hand to put the lid on.
- Quickly place the canister upside-down on a level surface and stand back. Be sure to keep your head well back from the canister.
How high does the film canister fly? Where does the energy come from to make the canister move?
Mixing the vinegar and sodium bicarbonate starts a chemical reaction which produces carbon dioxide gas. The gas expands quickly and pressure builds up inside the film canister. The pressure is so strong that eventually the gas pushes the canister up off the lid.