- Alka-Seltzer tablets (from any chemist)
- Tap water
- 35mm film canister or small container with a fitting lid that can pop off (like M&Ms!)
- Divide the Alka-Seltzer tablet into quarters
- Fill the container with 1/3 of wate.
- Drop a quarter of the tablet into the container
- Put the lid on and give your rocket a quick shake
- QUICKLY place the rocket, lid down, in the launch zone!
- Countdown and wait for the rocket to launch!
First up, you'll notice some fizzing and bubbling going on. This is due to a reaction between the acid and base that are in the tablet. When these mix they react and release Carbon Dioxide - Co2. A great chemical reaction.
The gas released builds up the pressure inside the canister. Soon there is too much pressure inside and its gives way at its weakest point. A great example of how gas takes up more space than solids and liquids.
And finally, as Newton said, something wont start moving until a force makes it. This is pretty obvious in this experiment. Also, we see a great demonstration of Newton's third law - If there is a force in one direction, there is as much force in the opposite direction.
It is getting harder to find 35mm film canisters but ask in the Kodak shops. We always manage to get a couple.