Wait for it…
Want to try it? You’ll need:
a Mini M&Ms canister – cut the lid off the body
a little bit of clay or gum
Alka-Seltzer tablets – break into quarters
decorations if you want them (washi tape, stickers, Sharpie markers, foil for a shiny nose cone)
Decorate your canister (I didn’t because I was just trying to make sure it worked first). My nose cone is a semi-circle of card stock taped together to make a cone and hot glued in place. Stick the little bit of clay in the lid. This is to delay the reaction of the Alka-Seltzer so that you can take your time. I wish I could remember where I saw about the clay. Thank you, Mysterious Blogger who is probably also a Homeschooler!
When you are ready to launch, stick 1/4 of an Alka-Selzer tablet into the clay, put about a tablespoon of water into the canister, and put the lid on top. DON’T FLIP THE ROCKET OVER until you are ready to start the reaction!
Flip it over, set it on the ground (top down) and move away. Pop!
Troubleshooting: Go easy on the water. Too much and it just leaks out as the pressure builds – you need space inside the canister for the CO2 to build up.
Film canisters also work (the Fuji kind especially since the lids sink into the canister) but Mini M&Ms are much easier to come by these days.