Empty film canister
Design your rocket, drawing it on paper. A simple cylinder, nose cone, and a pair of fins will suffice. It should stand around 6 inches (15 cm) tall and be approximately 1½ inches (3.75 cm) in diameter.
Cut out your rocket components (cylinder, nose cone, and fins) and glue them together.
Open the film canister and drop one-half of an Alka-Seltzer tablet into it.
Fill the canister half full of water and snap the canister cap into place. Slide the rocket over the cap, place the assembly cap-down, and get back. Watch the rocket blast off.
This project was excerpted from The Big Book Of Hacks: 264 Amazing DIY Tech Projects, a compendium of ingenious and hilarious projects for aspiring makers. Buy it here. And for more amazing hacks, go here.