4 Things You Can Do With Dry Ice (Besides Make Fake Fog)

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.

More Details Emerge About 'Oumuamua, Earth's First-Recorded Interstellar Visitor

In October, scientists using the University of Hawaii's Pan-STARRS 1 telescope sighted something extraordinary: Earth's first confirmed interstellar visitor. Originally called A/2017 U1, the once-mysterious object has a new name—'Oumuamua, according to Scientific American—and researchers continue to learn more about its physical properties. Now, a team from the University of Hawaii's Institute of Astronomy has published a detailed report of what they know so far in Nature.

Fittingly, "'Oumuamua" is Hawaiian for "a messenger from afar arriving first." 'Oumuamua's astronomical designation is 1I/2017 U1. The "I" in 1I/2017 stands for "interstellar." Until now, objects similar to 'Oumuamua were always given "C" and "A" names, which stand for either comet or asteroid. New observations have researchers concluding that 'Oumuamua is unusual for more than its far-flung origins.

It's a cigar-shaped object 10 times longer than it is wide, stretching to a half-mile long. It's also reddish in color, and is similar in some ways to some asteroids in our solar system, the BBC reports. But it's much faster, zipping through our system, and has a totally different orbit from any of those objects.

After initial indecision about whether the object was a comet or an asteroid, the researchers now believe it's an asteroid. Long ago, it might have hurtled from an unknown star system into our own.

'Oumuamua may provide astronomers with new insights into how stars and planets form. The 750,000 asteroids we know of are leftovers from the formation of our solar system, trapped by the Sun's gravity. But what if, billions of years ago, other objects escaped? 'Oumuamua shows us that it's possible; perhaps there are bits and pieces from the early years of our solar system currently visiting other stars.

The researchers say it's surprising that 'Oumuamua is an asteroid instead of a comet, given that in the Oort Cloud—an icy bubble of debris thought to surround our solar system—comets are predicted to outnumber asteroids 200 to 1 and perhaps even as high as 10,000 to 1. If our own solar system is any indication, it's more likely that a comet would take off before an asteroid would.

So where did 'Oumuamua come from? That's still unknown. It's possible it could've been bumped into our realm by a close encounter with a planet—either a smaller, nearby one, or a larger, farther one. If that's the case, the planet remains to be discovered. They believe it's more likely that 'Oumuamua was ejected from a young stellar system, location unknown. And yet, they write, "the possibility that 'Oumuamua has been orbiting the galaxy for billions of years cannot be ruled out."

As for where it's headed, The Atlantic's Marina Koren notes, "It will pass the orbit of Jupiter next May, then Neptune in 2022, and Pluto in 2024. By 2025, it will coast beyond the outer edge of the Kuiper Belt, a field of icy and rocky objects."

Last month, University of Wisconsin–Madison astronomer Ralf Kotulla and scientists from UCLA and the National Optical Astronomy Observatory (NOAO) used the WIYN Telescope on Kitt Peak, Arizona, to take some of the first pictures of 'Oumuamua. You can check them out below.

Images of an interloper from beyond the solar system — an asteroid or a comet — were captured on Oct. 27 by the 3.5-meter WIYN Telescope on Kitt Peak, Ariz.
Images of 'Oumuamua—an asteroid or a comet—were captured on October 27.

U1 spotted whizzing through the Solar System in images taken with the WIYN telescope. The faint streaks are background stars. The green circles highlight the position of U1 in each image. In these images U1 is about 10 million times fainter than the faint
The green circles highlight the position of U1 in each image against faint streaks of background stars. In these images, U1 is about 10 million times fainter than the faintest visible stars.
R. Kotulla (University of Wisconsin) & WIYN/NOAO/AURA/NSF

Color image of U1, compiled from observations taken through filters centered at 4750A, 6250A, and 7500A.
Color image of U1.
R. Kotulla (University of Wisconsin) & WIYN/NOAO/AURA/NSF

Editor's note: This story has been updated.

Scientists Analyze the Moods of 90,000 Songs Based on Music and Lyrics

Based on the first few seconds of a song, the part before the vocalist starts singing, you can judge whether the lyrics are more likely to detail a night of partying or a devastating breakup. The fact that musical structures can evoke certain emotions just as strongly as words can isn't a secret. But scientists now have a better idea of which language gets paired with which chords, according to their paper published in Royal Society Open Science.

For their study, researchers from Indiana University downloaded 90,000 songs from Ultimate Guitar, a site that allows users to upload the lyrics and chords from popular songs for musicians to reference. Next, they pulled data from labMT, which crowd-sources the emotional valence (positive and negative connotations) of words. They referred to the music recognition site Gracenote to determine where and when each song was produced.

Their new method for analyzing the relationship between music and lyrics confirmed long-held knowledge: that minor chords are associated with sad feelings and major chords with happy ones. Words with a negative valence, like "pain," "die," and "lost," are all more likely to fall on the minor side of the spectrum.

But outside of major chords, the researchers found that high-valence words tend to show up in a surprising place: seventh chords. These chords contain four notes at a time and can be played in both the major and minor keys. The lyrics associated with these chords are positive all around, but their mood varies slightly depending on the type of seventh. Dominant seventh chords, for example, are often paired with terms of endearment, like "baby", or "sweet." With minor seventh chords, the words "life" and "god" are overrepresented.

Using their data, the researchers also looked at how lyric and chord valence differs between genres, regions, and eras. Sixties rock ranks highest in terms of positivity while punk and metal occupy the bottom slots. As for geography, Scandinavia (think Norwegian death metal) produces the dreariest music while songs from Asia (like K-Pop) are the happiest. So if you're looking for a song to boost your mood, we suggest digging up some Asian rock music from the 1960s, and make sure it's heavy on the seventh chords.


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