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.     

Pioneering Heart Surgeon René Favaloro Is Being Honored With a Google Doodle

Dr. René Favaloro (left) pictured with colleague Dr. Mason Sones.
Dr. René Favaloro (left) pictured with colleague Dr. Mason Sones.
The Cleveland Clinic Center for Medical Art & Photography, Wikimedia Commons // CC BY 4.0

Argentinian heart surgeon René Favaloro is the subject of today’s Google Doodle, which features a sketched portrait of the doctor along with an anatomical heart and several medical tools, The Independent reports.

The renowned doctor was born on this day in 1923 in La Plata, the capital of Argentina’s Buenos Aires province, and pursued a degree in medicine at La Plata University. After 12 years as a doctor in La Pampa, where he established the area’s first mobile blood bank, trained nurses, and built his own operating room, Favaloro relocated to the U.S. to specialize in thoracic surgery at the Cleveland Clinic.

In 1967, Favaloro performed coronary bypass surgery on a 51-year-old woman whose right coronary artery was blocked, restricting blood flow to her heart. Coronary bypass surgery involves taking a healthy vein from elsewhere in the body (in this case, Favaloro borrowed from the patient’s leg, but you can also use a vein from the arm or chest), and using it to channel the blood from the artery to the heart, bypassing the blockage. According to the Mayo Clinic, it doesn’t cure whatever heart disease that caused the blocked artery, but it can relieve symptoms like chest pain and shortness of breath, and it gives patients time to make other lifestyle changes to further manage their disease.

Favaloro wasn’t keen on being called the “father” of coronary bypass surgery, but his work brought the procedure to the forefront of the clinical field. He moved back to Argentina in 1971 and launched the Favaloro Foundation to train surgeons and treat a variety of patients from diverse economic backgrounds.

Favaloro died by suicide on July 29, 2000, at the age of 77, by a gunshot wound to the chest. His wife had died several years prior, and his foundation had fallen deeply into debt, which Argentinian hospitals and medical centers declined to help pay, The New York Times reported at the time.

“As a surgeon, Dr. Favaloro will be remembered for his ingenuity and imagination,” his colleague Dr. Denton A. Cooley wrote in a tribute shortly after Favaloro’s death. “But as a man ... he will be remembered for his compassion and selflessness.” Today would have been his 96th birthday.

[h/t The Independent]

Forget Lab-Grown Meat—You Can Now Buy Lab-Grown Ice Cream

Deagreez/iStock via Getty Images
Deagreez/iStock via Getty Images

Even though “dairy-free” doesn’t necessarily mean “healthier,” it’s still a necessary disclaimer for dairy-free people who are screaming for ice cream. And between veganism, lactose intolerance, and other dietary dairy restrictions, the race is on to create an ice cream for the masses that doesn’t taste like chalk, chemicals, or sadness.

Bay Area startup Perfect Day may have just pulled ahead of the competition. Today, Fast Company reports, it released three flavors of dairy-free ice cream—Vanilla Salted Fudge, Milky Chocolate, and Vanilla Blackberry Toffee—that contain the same proteins found in cow dairy, but grown in a lab from engineered yeast and DNA. Since those proteins contribute greatly to the rich texture and taste of ice cream that we love so much, Perfect Day’s products are supposedly indistinguishable from the real thing.


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The co-founders, vegan bioengineers Ryan Pandya and Perumal Gandhi, got the idea from their experience in medicine, where fermentation is used to grow things in a lab all the time. “The two of us started scratching our heads and wondering, what if we just apply that same exact technology that’s been around for half a century to make the world’s most in-demand, highest-quality protein?” Pandya explained to Fast Company.

Their lactose-, dairy-, and gluten-free vegan ice cream, which they’ve been working on for five years, includes the dairy proteins casein and whey, as well as plant-based fats and sugar. If you're dairy-free because of a casein or whey allergy or sensitivity, you should treat this ice cream like you would any other foods containing dairy, and heed the "Contains milk protein" disclaimer on Perfect Day products.

Lab-grown dairy has environmental benefits too, considering that cows and other livestock are major culprits of greenhouse gas emissions. Pandya and Gandhi hope to sell their proteins to large-scale food manufacturers, and have teamed up with Archer Daniels Midland, an Illinois-based food processing company, to increase production.

Though it seems like a scoop or two of this ice cream might be the recipe for a perfect day, that wasn’t the inspiration behind the company’s name—the founders stumbled upon a study in which scientists discovered that cows produced more milk when listening to music, and one of the most successful songs was Lou Reed’s “Perfect Day.” “As a company on a mission to make cows, people, and the planet happier, it seemed like a perfect fit,” the website says.

Can’t wait to taste the magic? You can purchase all three flavors in a three-pint bundle for $60 here.

[h/t Fast Company]

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