What science experiments can I do with a balloon full of carbon dioxide?

November 3, 2013 7:21 PM

This Halloween I did some Halloween candy science experiments with my nieces and nephew. One of the experiments we didn't get to do (but soon will) is: Pouring Pop Rocks into a bottle of pop will make all that pent-up carbon dioxide escape but not fizz over. If you put the rocks into a balloon, then fit the balloon over the bottle's mouth and let the rocks fall in, it inflates the balloon with carbon dioxide. But what can I do with a balloon full of carbon dioxide? ...Is it a stupid idea to inhale it to see if I get a funny voice?

I'm thinking I could affix a thermometer inside each, get transparent balloons, and fill one balloon with CO2 and one with ordinary air. Then shine a heat lamp on both at equal distances to illustrate that CO2 traps heat better than ordinary air.

What else could I do?

posted by Jacob Knitig to Science & Nature (12 answers total)

Don't inhale it to see if you'll get a funny voice. You won't, and it's an asphyxiation risk.

You could try to put out a burning candle or smouldering object in a jar, perhaps? Comparing what happens if you blow lightly on a naked flame.
posted by Fiasco da Gama at 7:25 PM on November 3, 2013 [4 favorites]

You can "pour" carbon dioxide onto a candle to put it out - it's heavier than air and will displace it.
posted by O9scar at 7:35 PM on November 3, 2013 [2 favorites]

One lungful of CO2 probably won't hurt you, but you might be left gasping, as your lungs will correctly think they aren't trading CO2 for O2 effectively and will speed up your respiration. Probably not the best physiological experiment.

I would definitely do the extinguish-a-candle experiment. It's the standard.

Are they too young to read "The Invention of Air", about Joseph Priestley ?
posted by Kakkerlak at 7:36 PM on November 3, 2013 [3 favorites]

Carbon Dioxide is heavier than air, so it will make your voice lower.
posted by rhizome at 8:16 PM on November 3, 2013

Don't try inhaling it - it is an asphyxiation risk and it also triggers panic attacks. CO2 is denser than air, so not only can you pour it to put out a candle, but a balloon full of it will sink compared to a balloon full of air.

The heat lamp experiment is interesting but how well it works will likely depend on the exact spectrum of your heat lamp - the absorption windows for CO2 aren't that broad. See here for an introduction.
posted by pombe at 8:19 PM on November 3, 2013

Best answer: Inhaling carbon dioxide is not an asphyxiation risk for anybody except those with severely diminished respiratory systems. The inhalation triggers a reflex which results in...breathing, so as long as you talk while exhaling, the experiment will conclude as normal. The panic attacks happen among those who don't have enough lung power to exhale the CO2 completely, or, as illustrated by some of the studies linked, are wearing a mask that artificially increases the amount of CO2 in the air being breathed. Sorry for the derail.
posted by rhizome at 8:58 PM on November 3, 2013 [3 favorites]

In my personal experience inhaling CO2 through the nose produces carbonic acid (I think) which irritates the nasal passages and results in intense sneezing. Ymmv.

Inhalation of a really heavy gas does make your voice lower, but it's not easy to get the heavy gas out of your lungs efficiently.
posted by anadem at 9:05 PM on November 3, 2013

Best answer: You are unlikely to asphyxiate inhaling from a single balloon full of CO₂. What you will get is a stabbing pain in the chest as the mechanism your body uses to remind you to breath informs you that NOW would be a good time.

The real issue with experimenting with gasses is handling them requires some pretty specialized equipment, so transferring heavier than air CO₂ filled balloon into a container so that you can pour it over a candle is a bit of a trick. You can try filling the container with water and holding it upside down in a sink full of water and then using a bit of tubing to transfer the CO₂ into your container where it will displace the water (like so, only with your balloon replacing the test tube and Bunsen burner). Try it with a balloon filled with air a few times until you get good at it. (Or cut out the middle man and collect the fizz from your pop rocks in a tube full of water.)

Heck, just playing around with some tubing and balloons and water and just air with your nieces and nephew might be a fun educational thing to do.
posted by Kid Charlemagne at 9:07 PM on November 3, 2013

Best answer: Inhaling carefully from a balloon full of CO₂ will instantly teach you what really needing to breathe feels like, and after the subsequent gasping has subsided you will find out what strong hyperventilation feels like.

Don't do it to your kids though, and don't do it where they can see you, because they will want to try it and doing so will probably cause them quite a lot of distress. The experience is unpleasant.
posted by flabdablet at 12:16 AM on November 4, 2013

The real issue with experimenting with gasses is handling them requires some pretty specialized equipment

Not necessarily.
posted by flabdablet at 12:24 AM on November 4, 2013

Best answer: If you blow air soap bubbles into a tank half filled with CO2, they would float at the interface between the CO2 and the normal Air. You can do the same thing with a solid boat, provided you can make one light enough.

Google boat float CO2 and you can get some examples, but I think a lot of them involve SF6 instead of CO2 because the difference in density is greater.

The standard one is to have three or four candles of different heights burning in a fishtank and pour the CO2 into the fishtank and watch as they get snuffed out by the growing CO2 layer.
posted by koolkat at 1:13 AM on November 4, 2013

Response by poster: Flabdablet: Hilarious video. Thanks.
posted by Jacob Knitig at 7:49 AM on November 4, 2013