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.     


This Outdoor Lantern Will Keep Mosquitoes Away—No Bug Spray Necessary

Thermacell, Amazon
Thermacell, Amazon

With summer comes outdoor activities, and with those activities come mosquito bites. If you're one of the unlucky people who seem to attract the insects, you may be tempted to lock yourself inside for the rest of the season. But you don't have to choose between comfort and having a cocktail on the porch, because this lamp from Thermacell ($25) keeps outdoor spaces mosquito-free without the mess of bug spray.

The device looks like an ordinary lantern you would display on a patio, but it works like bug repellent. When it's turned on, a fuel cartridge in the center provides the heat needed to activate a repellent mat on top of the lamp. Once activated, the repellent in the mat creates a 15-by-15-foot bubble of protection that repels any mosquitos nearby, making it a great option for camping trips, days by the pool, and backyard barbecues.

Mosquito repellent lantern.

Unlike some other mosquito repellents, this lantern is clean, safe, and scent-free. It also provides light like a real lamp, so you can keep pests away without ruining your backyard's ambience.

The Thermacell mosquito repellent lantern is now available on Amazon. If you've already suffered your first mosquito bites of the summer, here's some insight into why that itch can be so excruciating.

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

Map Shows How Everyone Blamed Syphilis on Everyone Else

Portrait of Gerard de Lairesse by Rembrandt van Rijn. De Lairesse, a painter and art theorist, had congenital syphilis that deformed his face and eventually blinded him.
Portrait of Gerard de Lairesse by Rembrandt van Rijn. De Lairesse, a painter and art theorist, had congenital syphilis that deformed his face and eventually blinded him.
Gerard de Lairesse, Wikimedia Commons // Public Domain

The origins of syphilis may be one of the greatest (and grossest) health mysteries of our time. Some historians claim that Christopher Columbus and his sailors contracted the sexually transmitted disease in the New World and brought it back to Europe. Other experts believe that the disease, which is caused by the bacterium Treponema pallidum, existed in various forms around the globe but was simply misclassified as other conditions. (European writers, including Italian historian Niccolo Squillaci, first described syphilis in the late 15th century.) And in 2015, researchers announced that they had identified signs of congenital syphilis in 14th-century skeletons from St. Polten, Austria, adding new evidence to an ages-old debate.

One thing's for sure: As the map below illustrates, nobody wanted to take credit for originating the virulent condition. Created by Redditor masiakasaurus (and spotted by The A.V. Club), the map illustrates the various nicknames Europeans gave the disease before the name syphilis caught on. (Italian physician and poet Hieronymus Fracastorius coined the word in 1530 with his poem "Syphilis Sive Morbus Gallicus" ("Syphilis or the French Disease"). Not surprisingly, nearly every single moniker used for the disease places blame on another group for giving birth to what by then had become a continental scourge.

“Most physicians felt that this was a new disease, that it hadn’t been seen before in Europe, and that view tended to prevail for quite some time,” medical historian John Parascandola told The Atlantic in 2016. “There were certain tempting reasons for people to accept that—blame it on the others, blame it on the outsiders. Before that, the French were blaming it on the Italians, the Italians were blaming it on the French, et cetera.”

Masiakasaurus sourced the syphilis nicknames from nine scholarly books/journals, including The Early History of Syphilis: A Reappraisal,The rise and fall of sexually transmitted diseases in Sweden, and A Medical History of Persia and the Eastern Caliphate: From the Earliest Times Until the Year A.D. 1932. You can view the full list on Reddit—after giving silent thanks to Alexander Fleming for discovering penicillin, found to be an effective cure for syphilis in 1943.

[h/t The A.V. Club]