Alka-Seltzer Rocket

Dry ice is solid carbon dioxide. It is sold in some grocery stores, fish markets, and specialty stores. The Alka-Seltzer rocket can be repeated using dry ice in place of Alka-Seltzer. Do not use water, but place a small piece of dry ice into the canister. 

Put on your safety glasses. To make a rocket, fill a film canister about / full of water. Place the canister in the center of the pie pan. Break an Alka-Seltzer tablet into three piece of about equal size. Drop one of the pieces into the canister, snap on its top, and quickly invert the canister so its top is resting on the pie pan. Step back and wait. The pressure inside the canister increases due to the accumulation of carbon dioxide gas inside it. This pressure builds up until the canister body suddenly explodes from the pie pan launching pad. If the top of the canister is quickly replaced and the canister repositioned, another blast can occur. In fact, several blast-offs can be obtained with one Alka-Seltzer tablet. 

This step requires you to be quick. Drop the broken antacid tablet into the container, then quickly close the lid and place the canister on the ground with the cap side down. Stand back a good distance, and wait for the rocket to launch. The Alka-Seltzer will react with the water in a reaction that produces carbon dioxide gas. The pressure of this gas will build and build until it exerts a force so great that it will blast the canister off of the cap, shooting the canister into the air. 

Try repeating this experiment using different ratios of Alka-Seltzer to water, or using canisters of different types or sizes. You might also compare different brands of antacid tablets, or different methods for crushing the tablet before you add it to the canister. Compete with your friends to see who can make the rocket that shoots the highest ... 

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