Step 1: Materials
1 Film Canister - The kind where the lid snaps in, they are usually translucent white.
1 Plastic Syringe - Ask at your local drugstore for an Oral Syringe.
Baking Soda - Doesn't matter how much.
Vinegar - Again doesn't matter how much.
Paper - Plain printer paper, or construction paper if you like colour.
Tape - Regular scotch tape.
Scissors - They only need to be able to cut paper.
Step 2: Constucting the Rocket
Now cut a circle about 8 cm in diameter out of your paper, make a radial cut to the center of the circle. take one edge and slide it over the other edge, keep sliding it and it should start to form a cone, do this this until the base of the cone is the same size as the top of the film canister. Tape the cone all over and this will be the rockets nose.
Now cut 3 2cm x 20cm strips of paper and fold them until you have 3 2cm x 2cm squares, tape the squares so they will not unfold then cut them to what ever fin design you think looks coolest as these fins contribute little to the stabilization and flight. Tape them on to the Film Canister so the top is the closed end. tape on the nose cone now as well.
There you go, you have a rocket.