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Q:
why does a film canister shoot in the air when you dissolve an effervescent pain tablet in it
- james hatfield (age 11)
matewan middle school, matewan, wv usa
A:
ames -
I think the activity you're refering to is this: Take a film
canister and put some water in it. Drop an effervescent pain pill (like
Alka-Seltzer) in and close the lid. Keeping the canister pointed away
from you, the lid should pop off and go flying into the air.
The reason for this is a chemical reaction between the pill and the
water. Pain pills like this contain a chemical called sodium
bicarbonate (also known as baking soda). When the sodium bicarbonate
reacts with water, it forms carbon dioxide, which is a gas. Gases like
carbon dioxide take up a lot of space, so the lid is pushed off of the
container to make way, sending it flying!
-Tamara
(published on 10/22/2007)
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