(a kinetic energy science demonstration)
demonstration relies on a chemical reaction to 'blow'
the lid off the canister. It is rather dramatic and bound
to get a few 'Wow!!!' type responses.
- safety goggles
- 1 film canister (must seal internally)
- 1 alka-seltzer tablet
- a small amount of water
- 1 towel
- 1 ice-cream container lid
Place the ice-cream container lid on the ground in a clear
Pour approximately 1cm of water into the film canister.
Place the alka-seltzer tablet into the film canister and
put the lid on very quickly.
Quickly place the bottom of the film canister on the ice-cream
container lid with the bottom of the canister and step
Pair Share - How do you think the rocket works?
The water causes a chemical reaction with the alka-seltza
tablet that produces the gas carbon dioxide. The carbon
dioxide continues to be produced but it has no where to
go and as a result builds up pressure in the canister.
Eventually the pressure becomes too great and the lid
is pushed off.
/ Further Investigation:
- Repeat the demonstration but invert the canister (turn
the canister up the other way).
Which went higher the lid or the canister? Why?
Try adding fins to the rocket. Does this have any effect
on height or direction of flight?
Add a 'nose cone' by creating a small cone from paper.
Does this have an effect?
Experiment with different levels of water and a stop watch
to see if you can work out how long until it blows.
Create a two stage rocket by taping two canisters together.
Substitute the alka-seltza tablet for bicarbonate soda.
Does this give better results.
- If you do this activity at the beginning of the year
& manage leave a mark on the roof, the kids will proudly
recount the story of how the mark got there to any visitor
will to listen :-)