Dry ice—or solid carbon dioxide, as it’s more specifically called—is a staple item in middle and high school science classes. But it’s also easily obtainable for anyone who wants to experiment with it in the comfort of his or her own home. While you still need to take precautions when handling it—don’t ever touch it with bare hands—it’s innocuous enough that it’s sold at most supermarkets.
[Image courtesy of Herkie's Flickr photostream]
So what can you do with dry ice? Sure, you can make artificial fog and other smoky special effects. But the possibilities certainly don’t end there. Here are just a few other things to do with solid carbon dioxide.
1. Power a rocket
If you mix dry ice with water, it will sublime—that is, change from a solid to a gas without existing in a liquid phase in between. If sublimation happens within an enclosed container, the carbon dioxide that’s produced will build up and this pressure will eventually cause a small explosion. With a few extra steps, you can use this same explosive reaction to send a basic rocket soaring.
There are dozens of ways to make dry ice rockets—and just as many YouTube demonstrations. But one of the simplest methods requires little more than a soda bottle and a cardboard box. (The guys in the above video didn't use a box; the box isn't necessary, but using one is a good way to ensure that you get the best possible launch.)
First, cut a hole in the base of the box that’s the same size as the bottle top; this is where you’ll put your projectile when you’re ready to launch it. Then cut or drill a small hole in the top of the bottle so that the gas can escape, and cover the hole with some Scotch tape.
Put enough water in the bottle so that it’s about 1/3 full and then add dry ice until it’s half full. Quickly close the bottle, stand it upside-down in the cardboard box, and wait—from a safe distance—for your rocket to take off. Just make sure to be careful; some dry ice rockets have a tendency to launch themselves horizontally.
2. Make root beer
Since dry ice is simply solid carbon dioxide—and carbon dioxide is what gives soda its fizz—you can use a chunk of the stuff to make your own carbonated beverage.
To make one gallon of root beer, take one gallon of water, two pounds of dry ice, and two ounces of root beer extract. Some recipes call for two cups of sugar as well; depending on what root beer extract you’re using, this might not be necessary.
Mix the water, extract, and sugar (if you’re using it) in a large container—one with a volume of at least four gallons and a sealable lid. Drop the dry ice, in chunks, into the liquid with tongs. Cover the container, but open it every so often in order to stir the solution and release some of the pressure building up inside so it doesn’t explode.
In about an hour, your root beer should be ready for consumption. Just make sure there are no solid chunks of dry ice remaining when you go to drink your concoction; while gaseous carbon dioxide can be consumed without concern, solid carbon dioxide can do serious damage to your internal organs. You can use this same procedure to make seltzer water if you omit the root beer extract.
3. Preserve your produce
Dry ice can be used to flash freeze food, and it’s a better way to freeze fruit and veggies than simply storing them in a conventional freezer. Produce that’s flash frozen will retain its initial texture and won’t get soggy when defrosted.
To flash freeze your food, get a seven to 10 pound bag of dry ice and put it in a large cooler. Place whatever fruits and veggies you want to freeze on a cookie sheet and then set the cookie tray on top of the dry ice. Close the cooler, and when your food is fully frozen, you can transfer it to your conventional freezer and save it for however long you like.
4. Protect yourself from pests
Mosquitoes and other insects are attracted to carbon dioxide gas; thus, dry ice can be used to lure these bugs away from their human targets. By hanging a cloth bag with a five-pound block of dry ice inside next to a mosquito lamp, you can significantly increase the trap’s efficacy. Strategically placed chunks of dry ice can be used to attract bed bugs as well.
Some people use dry ice to keep their terrariums free from unwanted bugs; removing the animals, placing a few cups of solid carbon dioxide and hot water in the base of the tank, then covering the tank and letting it sit for five minutes apparently works wonders. After five minutes passes, simply take out the cups, cover the tank, and let it stand for two or three hours before putting your animals back in.