Create a nose cone for the rocket by cutting a circle out of construction paper, using scissors to make a cut to the center, and bending it into a cone shape that you can tape to the end of the tube opposite the film canister so it looks like the second picture.
Hold your rocket upside down and fill the film canister about halfway or so with vinegar. If you want it to go faster, add more. But beware, don't make the same mistake it did when I added too much vinegar. (It exploded in my hands, ouch!)
The baking soda and vinegar will react to form carbon dioxide (a gas that has one carbon atom and two oxygen atoms), and the pressure created by the gas will force the lid off the container, launching your rocket into the air and crashing down.
Please, launch the rocket outdoors to prevent it from hitting someone or his/her property.This thing can shoot pretty high, so be very carefull! Happy making!
(As you can see It was icy outside when I made this. I made it in February.)
Or you don't even need the body, you could just shoot the canister itself.