Caution: this rocket can fly up to 3-4m. Adult supervision required.

You will need:

Film canister with lid (clear film canisters where the lid presses inside work the best)
Baking powder
Vinegar
Teaspoon
Toilet paper

What to do:

Take the lid off the film canister.
Measure three teaspoons of vinegar into the canister.
Take a sheet of toilet paper and place it on top of the canister.
Press it down to form a small well. Don’t press it down so far that it touches the vinegar! The aim is to keep the two ingredients apart.
Place a teaspoonful of baking powder in the well.
Press the lid on tightly and trim the excess toilet paper from the edges.
Do not turn it over yet and definitely DO NOT SHAKE IT! You don’t want it to go off and hit you in the eye.
Find a clear, safe area outdoors. It is not a good idea to do it where a slumbering dog or nervous cat is in the vicinity. Come to think of it make sure grandma or granddad are not snoozing in the garden either.
Turn the canister over and place it lid-down on the ground then retreat to a safe distance i.e. at least 2m away.
Brace yourself. It will take about 20 seconds or so to launch. The advantage of the clear canister is that you can see the mixture bubbling up. This means that you don’t have to get impatient and approach it just as it shoots up.
Whe-hay! Thar she blows! If you’re lucky it will go over the shed much to the pleasure of any watching kids.

What’s going on?

Vinegar and baking powder react together to form carbon dioxide gas. The gas builds up until it forces the lid off the film canister. The gas pushes downwards which in turn (thanks to Newton and his Third Law) causes the canister to be forced upwards.