Experiments with KVRR Meteorologist Scott Sincoff – Alka-Seltzer Rockets

Fun and Easy Science Experiments

This week, Meteorologist Scott Sincoff worked with Concordia Science Academy‘s Dr. Graeme Wyllie on a cool and explosive experiments – Alka-Seltzer Rockets!

Blast Off with Alka-Seltzer Rockets

For anyone out there who still has some old film canisters lying around, here’s a chance to take something simple and actually do some rocket science. If you don’t have any of the cans, they can be bought online or try and find something that has a tight enough lid that can pop off under pressure and launch in the air.

We are now going to take a few film canisters and make them into rockets. First, to check the rocket for leaks, grab the film canister and the lid. Push the lid on top of the film canister and make sure it’s real tight. You should hear a popping noise when you take it off. We need to make sure it’s nice and tight because we’re going to need it to go up to bursting strength. We’re going to take some tap water and fill the film canister about 1/5 full. Having a plate or a dish to launch from will keep the mess down. Take half an alka-seltzer tablet, drop it in, put the lid on, shake it three times and put it upside down on a flat surface. Count it down from 10 to 1 and watch it pop and fly skywards.


Make sure to take a few steps back after shaking and don’t ever get above it while it is waiting to launch. If you see water fizzing out of the bottom, have a grown up pick it up and pop it but be careful as they can still go-off with some force even if still leaking.

The Chemistry:

The Alka-Seltzer tablets contain citric acid and sodium bicarbonate (aka baking soda). The sodium bicarbonate reacts with the citric acid when placed in water and forms carbon dioxide gas, and that’s going to build up in pressure inside and BOOM!!!

Other Experiments:

  • Why not try to find other containers you can use. They should be made of plastic, not easy to break or shatter and have a lid that pops off with a little force. We’ve had some successes with plastic tubes and rubber stoppers but look around and see what else you can find
  • How high or how fast? In this experiment, it can help to shoot a little video with a phone to measure how high you can launch. Do this outside and use marks on the building like window ledges to measure how high they go. Try different amounts of alka-seltzers and water to see if you can find the best ratio. Does more water or less water make it go faster. Less water means more gas will build inside but does that help it go faster or higher. Does using a whole tablet make a difference or does it simply pop and the rest of the tablet is left behind?
  • This one should be done outside. Add some food color (very messy) or water soluble paint to the water and make starburst launch patterns where it takes off from… We often do this from paper and make all kind of patterns by doing lots of launches from the same paper.

Related Post