Alka Seltzer Rockets!

Here's a simple science project sure to please any kid from preschool up through grade school or so.

What You'll Need:
Empty toilet paper roll
Colored construction paper
Glue (hot glue works best)
Scissors
Plastic bag (optional but highly recommended)
Alka Seltzer tabs
Film canister with a lid that tucks inside the canister (Fuji film uses this type.)



(NOTE 9/9/14: Since this post was first published, film canisters have become harder to find. BUT empty Fuji canisters are pretty easily available online! Try looking on eBay or Etsy.)

 
How to Do It:

1. Cut a piece of construction paper the width of the toilet paper roll and long enough to fully wrap around the roll. Your child can color pictures or put stickers on the paper, if desired. Wrap the paper around the roll and glue in place. Hot glue is less little kid  friendly, but is quick and will hold up better than other types of glue.

2. Next, cut an approximately 3 1/2 inch circle of construction paper. With the scissors, clip a line halfway through it. Shape the circle into a pyramid and glue in place. Glue the pyramid onto the top of the toilet paper roll. (The rocket will hold up for more "take offs" if you make the pyramid-top from three layers; one layer of construction paper, one layer of plastic, and one more layer of construction paper. Trust me, your kids will want to launch the rocket over and over again, so I highly recommend this step.)

3. Break some Alka Seltzer tabs in two and place them in a bowl. Show your child what half a tab does in water. (It bubbles and foams.)

4. Warm some water in the microwave, or run some very warm tap water into a cup. Go outside and fill the film canister with some of the warm water. (Experiment with how much: Does half a canister work better than a full canister? What effect is there if you fill the canister 1/4 full?) Let your child drop half an Alka Seltzer in the canister, then quickly replace the top of the canister, place it on a flat surface, and stick the rocket on top of it. (Since this needs to be done quickly, if you have small children, you should probably do it.) A few seconds later, the canister top will pop off and the rocket will fly into the air.

5. Explain to your child that the Alka Seltzer bubbles and builds up gas (carbon dioxide) inside the canister; eventually, the canister can't contain the gas any longer, and it pops open, giving the rocket "fuel" to fly.

Young children squeal with delight each time you launch a rocket and older kids will have fun seeing whose rocket can fly highest or longest.