Why Do I Breathe Air?

chloe effron
chloe effron

Kids ask a lot of questions.

mental_floss has answers. This week we launched WHY?, our new series for kids and parents. We'll tackle all types of questions children have about how the world works by providing science-based, kid-friendly content. Our answers are written with early readers (ages 4 to 7) in mind, but we think they're interesting—and educational—for everyone.

Have a question? Send it to why@mentalfloss.com.

Air surrounds the surface of the Earth. Air is a mix of gases: 78 percent nitrogen, 21 percent oxygen, 1 percent argon, a little bit of carbon dioxide, and tiny amounts of 13 other gases. Plus, air contains water vapor, a mix of hydrogen and oxygen. Air is the part of the atmosphere closest to the Earth. Like a big blanket surrounding Earth, the atmosphere keeps us from getting too hot from the sun or too cold from space—and allows us to breathe. 

Land animals can’t exist without the oxygen in the air. More than 2.3 billion years ago the atmosphere was mostly nitrogen. But then the number of tiny microbes called cyanobacteria (SIGH-an-oh-back-TEER-e-uh) grew. Cyanobacteria use sunlight to change carbon dioxide into a kind of food—a process called photosynthesis. The waste product of photosynthesis is oxygen. So much oxygen was created that it began to fill up the atmosphere. After time, more animals evolved that were aerobic (air-OH-bick), meaning they need oxygen to survive—like us. 

Because plants photosynthesize! Remember, oxygen is a waste product of photosynthesis, and an important part of air. Without oxygen, we can’t breathe. Thanks for making oxygen, plants! But we do something for plants too. We breathe out carbon dioxide, which plants convert into simple food. So plants and animals work together to keep all creatures alive. How cool is that? 

For fun further reading about photosynthesis, visit this gardening guide for kids from the BBC.     


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

This article contains affiliate links to products selected by our editors. Mental Floss may receive a commission for purchases made through these links.

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]