A few months ago we shared a way to "catch" a gas in a liquid here...today we're sharing a similar gas-catching experiment with another exciting product: a balloon blown up with dry ice!
Actually any time you blow up a balloon, you are catching a gas (your breath, mostly carbon dioxide, but with signifcant amounts of oxygen and nitrogen) inside a solid (the balloon). If you have helium handy, it would be fun to blow up three balloons: one with helium, one with your breath, and two with carbon dioxide (one using dry ice and one using a vinegar/baking soda reaction like this one).
Anyway, on to this little experiment!
Dry ice is just frozen carbon dioxide. At room temperature carbon dioxide sublimates, or goes directly from a solid to a gas. If you place a small piece inside a balloon and tie a knot, the carbon dioxide will fill the balloon!
Easy Dry Ice Experiment:
* 12 inch balloon
* chunk of dry ice about the size of a blackberry
Easy How To:
1- Let everyone make a hypothesis about how long it will take to blow up the balloon OR what they think the balloon will look like after 1 minute and 10 minutes.
2- Carefully place the dry ice inside the balloon. Do not touch the dry ice with your hands. We used a spoon. I held the balloon open while one of my kids poured the little piece of dry ice into the balloon. There's no picture of this step because my hands were quite full! Using a 12-inch balloon makes this step a little easier than a smaller balloon. You may want to experiment with different sizes of dry ice...if the piece is too small, your balloon will never fill, but if the dry ice is too big, your balloon may pop!
3- Wait for the balloon to fill! We did a few other experiments during this time.
Here's our balloon after one minute:
After 5 minutes:
And after 10 minutes:
Your kids may notice that the balloon is heavier than a "normal" balloon (because carbon dioxide is heavier than "normal" air).
We also had fun watching the balloon over the next two days as it slowly shrunk. We decided that the balloon must lose carbon dioxide very slowly through its "skin" and the knot.
This is a super fun (and very visual) way to see dry ice changing to a carbon dioxide gas--it's great for a discussion on states of matter! There are also a lot of easy-to-control variables for your kiddos to experiment with and test any other hypotheses they may make about the balloons, dry ice, and/or the blowing-up-process!
I may share at any of these parties!
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