Balloon inflator #2
Objective
To use the gas from a soda bottle to inflate a balloon
Difficulty:
Time: a few minutes
Adult supervision: minimal
Dangers: none
Materials
1.5 L bottle of soda (unopened)
Balloon
Instructions
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Pre-stretch the balloon by inflating and deflating
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Open the bottle of soda and place the end of the balloon over the opening of the bottle
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Wait and see how long it takes for the balloon to start to inflate
The Science
The substance that makes fizzy drinks effervescent (that's another word for fizzy) is carbon dioxide. It is added to the soda under pressure. When the pressure is released, carbon dioxide gas starts to separate and we can see it as bubbles.
Further investigation
You could try using different sized bottles of soda. Does a soda bottle twice the size result in a balloon twice the size? Gee, older kids, you could get really technical here and try to work out the volumes.