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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.

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Penn Vet Working Dog Center
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Stones, Bones, and Wrecks
New Program Trains Dogs to Sniff Out Art Smugglers
Penn Vet Working Dog Center
Penn Vet Working Dog Center

Soon, the dogs you see sniffing out contraband at airports may not be searching for drugs or smuggled Spanish ham. They might be looking for stolen treasures.

K-9 Artifact Finders, a new collaboration between New Hampshire-based cultural heritage law firm Red Arch and the University of Pennsylvania, is training dogs to root out stolen antiquities looted from archaeological sites and museums. The dogs would be stopping them at borders before the items can be sold elsewhere on the black market.

The illegal antiquities trade nets more than $3 billion per year around the world, and trafficking hits countries dealing with ongoing conflict, like Syria and Iraq today, particularly hard. By one estimate, around half a million artifacts were stolen from museums and archaeological sites throughout Iraq between 2003 and 2005 alone. (Famously, the craft-supply chain Hobby Lobby was fined $3 million in 2017 for buying thousands of ancient artifacts looted from Iraq.) In Syria, the Islamic State has been known to loot and sell ancient artifacts including statues, jewelry, and art to fund its operations.

But the problem spans across the world. Between 2007 and 2016, U.S. Customs and Border Control discovered more than 7800 cultural artifacts in the U.S. looted from 30 different countries.

A yellow Lab sniffs a metal cage designed to train dogs on scent detection.
Penn Vet Working Dog Center

K-9 Artifact Finders is the brainchild of Rick St. Hilaire, the executive director of Red Arch. His non-profit firm researches cultural heritage property law and preservation policy, including studying archaeological site looting and antiquities trafficking. Back in 2015, St. Hilaire was reading an article about a working dog trained to sniff out electronics that was able to find USB drives, SD cards, and other data storage devices. He wondered, if dogs could be trained to identify the scents of inorganic materials that make up electronics, could they be trained to sniff out ancient pottery?

To find out, St. Hilaire tells Mental Floss, he contacted the Penn Vet Working Dog Center, a research and training center for detection dogs. In December 2017, Red Arch, the Working Dog Center, and the Penn Museum (which is providing the artifacts to train the dogs) launched K-9 Artifact Finders, and in late January 2018, the five dogs selected for the project began their training, starting with learning the distinct smell of ancient pottery.

“Our theory is, it is a porous material that’s going to have a lot more odor than, say, a metal,” says Cindy Otto, the executive director of the Penn Vet Working Dog Center and the project’s principal investigator.

As you might imagine, museum curators may not be keen on exposing fragile ancient materials to four Labrador retrievers and a German shepherd, and the Working Dog Center didn’t want to take any risks with the Penn Museum’s priceless artifacts. So instead of letting the dogs have free rein to sniff the materials themselves, the project is using cotton balls. The researchers seal the artifacts (broken shards of Syrian pottery) in airtight bags with a cotton ball for 72 hours, then ask the dogs to find the cotton balls in the lab. They’re being trained to disregard the smell of the cotton ball itself, the smell of the bag it was stored in, and ideally, the smell of modern-day pottery, eventually being able to zero in on the smell that distinguishes ancient pottery specifically.

A dog looks out over the metal "pinhweel" training mechanism.
Penn Vet Working Dog Center

“The dogs are responding well,” Otto tells Mental Floss, explaining that the training program is at the stage of "exposing them to the odor and having them recognize it.”

The dogs involved in the project were chosen for their calm-but-curious demeanors and sensitive noses (one also works as a drug-detection dog when she’s not training on pottery). They had to be motivated enough to want to hunt down the cotton balls, but not aggressive or easily distracted.

Right now, the dogs train three days a week, and will continue to work on their pottery-detection skills for the first stage of the project, which the researchers expect will last for the next nine months. Depending on how the first phase of the training goes, the researchers hope to be able to then take the dogs out into the field to see if they can find the odor of ancient pottery in real-life situations, like in suitcases, rather than in a laboratory setting. Eventually, they also hope to train the dogs on other types of objects, and perhaps even pinpoint the chemical signatures that make artifacts smell distinct.

Pottery-sniffing dogs won’t be showing up at airport customs or on shipping docks soon, but one day, they could be as common as drug-sniffing canines. If dogs can detect low blood sugar or find a tiny USB drive hidden in a house, surely they can figure out if you’re smuggling a sculpture made thousands of years ago in your suitcase.

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iStock
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Medicine
New Cancer-Fighting Nanobots Can Track Down Tumors and Cut Off Their Blood Supply
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iStock

Scientists have developed a new way to cut off the blood flow to cancerous tumors, causing them to eventually shrivel up and die. As Business Insider reports, the new treatment uses a design inspired by origami to infiltrate crucial blood vessels while leaving the rest of the body unharmed.

A team of molecular chemists from Arizona State University and the Chinese Academy of Sciences describe their method in the journal Nature Biotechnology. First, they constructed robots that are 1000 times smaller than a human hair from strands of DNA. These tiny devices contain enzymes called thrombin that encourage blood clotting, and they're rolled up tightly enough to keep the substance contained.

Next, researchers injected the robots into the bloodstreams of mice and small pigs sick with different types of cancer. The DNA sought the tumor in the body while leaving healthy cells alone. The robot knew when it reached the tumor and responded by unfurling and releasing the thrombin into the blood vessel that fed it. A clot started to form, eventually blocking off the tumor's blood supply and causing the cancerous tissues to die.

The treatment has been tested on dozen of animals with breast, lung, skin, and ovarian cancers. In mice, the average life expectancy doubled, and in three of the skin cancer cases tumors regressed completely.

Researchers are optimistic about the therapy's effectiveness on cancers throughout the body. There's not much variation between the blood vessels that supply tumors, whether they're in an ovary in or a prostate. So if triggering a blood clot causes one type of tumor to waste away, the same method holds promise for other cancers.

But before the scientists think too far ahead, they'll need to test the treatments on human patients. Nanobots have been an appealing cancer-fighting option to researchers for years. If effective, the machines can target cancer at the microscopic level without causing harm to healthy cells. But if something goes wrong, the bots could end up attacking the wrong tissue and leave the patient worse off. Study co-author Hao Yan believes this latest method may be the one that gets it right. He said in a statement, "I think we are much closer to real, practical medical applications of the technology."

[h/t Business Insider]

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