Why Doesn’t the Ocean Freeze?

Chloe Effron
Chloe Effron

WHY? is our attempt to answer all the questions every little kid asks. Do you have a question? Send it to why@mentalfloss.com.

Actually, it does! But only in some places where it's really, really cold, like the Arctic or Antarctica. Water is made of tiny molecules (MOL-uh-kyools) that move around a lot. As the temperature gets colder, the water molecules slow down. When the temperature falls to 32°F (F is short for Fahrenheit), these slow-moving molecules find each other and start sticking together to form ice crystals. 

Ocean water is different from fresh water, which you find in lakes, ponds, and rivers. Ocean water has salt dissolved in it. Salt has small particles called ions that surround the water molecules and keep them from sticking together to form ice. Ice will only begin to form when the ocean water gets even colder—about 29°F. 

As sea water gets colder, it gets denser. That means its molecules pack tightly together. Because it's more dense, this salty water begins to sink. That leaves less salty water on the top of the water. And this water begins to freeze. Sea ice has almost no salt in it. In fact, if you melt it, you can drink it!  

In places that get super cold, like around the North and South Poles, there is a lot of sea ice at the surface—especially in winter. That doesn’t mean the whole ocean is frozen, though. Under the ice, the ocean water is still there. Otherwise, it would be very hard for seals and fish to swim, and for Arctic polar bears and Antarctic penguins to dive below the icy surface to hunt them.   

More and more sea ice melts every year. To learn more about why this is important, watch this Discovery video on disappearing penguins

Amazon's Under-the-Radar Coupon Page Features Deals on Home Goods, Electronics, and Groceries

Stock Catalog, Flickr // CC BY 2.0
Stock Catalog, Flickr // CC BY 2.0

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Now that Prime Day is over, and with Black Friday and Cyber Monday still a few weeks away, online deals may seem harder to come by. And while it can be a hassle to scour the internet for promo codes, buy-one-get-one deals, and flash sales, Amazon actually has an extensive coupon page you might not know about that features deals to look through every day.

As pointed out by People, the coupon page breaks deals down by categories, like electronics, home & kitchen, and groceries (the coupons even work with SNAP benefits). Since most of the deals revolve around the essentials, it's easy to stock up on items like Cottonelle toilet paper, Tide Pods, Cascade dishwasher detergent, and a 50 pack of surgical masks whenever you're running low.

But the low prices don't just stop at necessities. If you’re looking for the best deal on headphones, all you have to do is go to the electronics coupon page and it will bring up a deal on these COWIN E7 PRO noise-canceling headphones, which are now $80, thanks to a $10 coupon you could have missed.

Alternatively, if you are looking for deals on specific brands, you can search for their coupons from the page. So if you've had your eye on the Homall S-Racer gaming chair, you’ll find there's currently a coupon that saves you 5 percent, thanks to a simple search.

To discover all the deals you have been missing out on, head over to the Amazon Coupons page.

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The Northern Lights Storms Are Getting Names—and You Can Offer Up Your Suggestions

A nameless northern lights show in Ylläs, Finland.
A nameless northern lights show in Ylläs, Finland.
Heikki Holstila, Flickr // CC BY-ND 2.0

While all northern lights are spectacular, they’re not all spectacular in the same way. Aurora borealis, or “northern dawn,” occurs when electrons in the magnetic field surrounding Earth transfer energy to oxygen and nitrogen molecules in the atmosphere. The molecules then emit the excess energy as light particles, which create scintillating displays whose colors and shapes depend on many known and unknown factors [PDF]—type of molecule, amount of energy transferred, location in the magnetosphere, etc.

Though the “storms” are extremely distinct from each other, they haven’t been named in the past the way hurricanes and other storms are christened. That’s now changing, courtesy of a tourism organization called Visit Arctic Europe. As Travel + Leisure reports, the organization will now christen the strongest storms with Nordic names to make it easier to keep track of them.

“There are so many northern lights visible in Arctic Europe from autumn to early spring that we started giving them names the same way other storms are named. This way, they get their own identities and it’s easier to communicate about them,” Visit Arctic Europe’s program director Rauno Posio explained in a statement.

Scientists will be able to reference the names in their studies, much like they do with hurricanes. And if you’re a tourist hoping to check out other people’s footage of the specific sky show you just witnessed, searching by name on social media will likely turn up better results than a broad “#auroraborealis.”

Visit Arctic Europe has already given names to recent northern lights storms, including Freya, after the Norse goddess of love, beauty, and fertility, and Sampo, after “the miracle machine and magic mill in the Finnish national epic poem, ‘Kalevala.’” A few other monikers pay tribute to some of the organization’s resident “aurora hunters.”

But you don’t have to be a goddess or an aurora hunter in order to get in on the action. Anybody can submit a name (along with an optional explanation for your suggestion) through the “Naming Auroras” page here. It’s probably safe to assume that submissions related to Nordic history or culture have a better chance of being chosen, but there’s technically nothing to stop you from asking Visit Arctic Europe to name a northern lights show after your dog.

[h/t Travel + Leisure]