This is a fun and simple craft you and your kid can do if you have any Alka-Seltzer tablets left over from making your own lava lamp.
All you need to do is:
1. Get a container that closes airtight. The smaller it is, the easier this experiment will be. We used old film canisters. (They make a satisfying *pop* noise that you can hear repeatedly in our video.) But you could even use a Ziploc bag as long as you close it securely.
2. Put water in the canister.
3. Drop in an Alka-Seltezer tablet.
4. Secure the top onto the canister so it's airtight.
5. Set the canister down and give it some space. The tablet and the water are interacting and creating carbon dioxide. Eventually, it will create too much gas for the container to hold and shoot its top off.
There won't be any fire in this explosion, but it could still hypothetically whack you in the eye; so it would be safest to wear goggles.
By the way, if you put less water in the canister, then it actually causes a bigger pop because it leaves space for more gas. However, you'll have to wait longer for your container to pop.
You can do a similar experiment with a Ziploc bag, warm water, baking soda and vinegar. Put the warm water in the bag first, then three scoops of baking soda wrapped in a tissue, and finally the vinegar. Make sure the bag is sealed completely shut or it will just leak instead of popping.
For more fun experiments and programs at Mentor Library, visit www.mentorpl.org.