Why Do Onions Make You Cry?

iStock/D-Keine
iStock/D-Keine

The onion has been traced back as far as the Bronze Age and was worshipped by the Ancient Egyptians (and eaten by the Israelites during their bondage in Egypt). Onions were rubbed over the muscles of Roman gladiators, used to pay rent in the Middle Ages, and eventually brought to the Americas, where today we fry, caramelize, pickle, grill, and generally enjoy them.

Many of us burst into tears when we cut into one, too. It's the price we pay for onion-y goodness. Here's a play-by-play breakdown of how we go from grabbing a knife to crying like a baby:

1. When you cut into an onion, its ruptured cells release all sorts of goodies, like allinase enzymes and amino acid sulfoxides. The former breaks the latter down into sulfenic acids.

2. The sulfenic acids, unstable bunch that they are, spontaneously rearrange into thiosulfinates, which produce a pungent odor and at one time got the blame for our tears. The acids are also converted by the LF-synthase enzyme into a gas called syn-propanethial-S-oxide, also known as the lachrymatory factor (or the crying factor).

3. Syn-propanethial-S-oxide moves through the air and reaches our eyes. The first part of the eye it meets, the cornea, is populated by autonomic motor fibers that lead to the lachrymal glands. When syn-propanethial-S-oxide is detected, all the fibers in the cornea start firing and tell the lachrymal glands to wash the irritant away.

4. Our eyes automatically start blinking and producing tears, which flushes the irritant away. Of course, our reaction to burning eyes is often to rub them, which only makes things worse since our hands also have some syn-propanethial-S-oxide on them.

It only takes about 30 seconds to start crying after you make the first cut; that's the time needed for syn-propanethial-S-oxide formation to peak.

WHY DON'T GREEN ONIONS MAKE US CRY?

The onion's relatives, like green onions, shallots, leeks and garlic, also produce sulfenic acids when cut, but they generally have fewer (or no) LF-synthase enzymes and don't produce syn-propanethial-S-oxide.

HOW DO I AVOID CRYING?

Since I usually go through a good deal of onions while cooking at home, I've been road testing some of the different methods the internet suggests for reducing or avoiding the effects of the lachrymatory factor. Here's what I tried:

Method #1: Chill or slightly freeze the onions before cutting, the idea being that this will change the chemical reactions and reduce the gas that is released.
Result: The onion from the fridge has me crying just as quickly as room temperature ones. The one that was in a freezer for 30 minutes leaves me dry-eyed for a bit, but by the time I'm done dicing my eyes start to burn a little.

Method #2: Cut fast! Get the chopping over with before the gas reaches your eyes.
Result: Just hacking away at the onion, I get in the frying pan without so much as a sting in my eyes. The onion looks awful, though. Doing a proper dice, I take a little too long and start tearing up. If you don't mind a mangled onion, this is the way to go.

Method #3: Put a slice of bread in your mouth, and cut the onion with most of the bread sticking out to "catch" the fumes.
Result: It seems the loaf of bread I have has gone stale. I stop the experiment and put bread on my shopping list.

Method #4: Chew gum while chopping. It keeps you breathing through your mouth, which keeps the fumes away from your eyes.
Result: This seems to work pretty well as long as you hold your head in the right position. Leaning toward the cutting board or looking right down at the onion puts your eyes right in the line of fire again.

Method #5: Cut the onions under running water. This prevents the gas from traveling up into the eyes.
Result: An onion in the sink is a hard onion to cut. I think Confucius said that. My leaky Brita filter is spraying me in the face and I'm terrified I'm going to cut myself, but I'm certainly not crying.

Method #6: Wear goggles.
Result: In an effort to maintain my dignity, I try my eyeglasses and sunglasses first. Neither do me any good. The ol' chemistry lab safety glasses make me look silly, but help a little more. I imagine swim goggles would really do the trick, but I don't have any.

Method #7: Change your onion. "Tear free" onions have been developed in the UK via special breeding and in New Zealand via "gene silencing" techniques.
Result: My nearest grocery store, Whole Foods, doesn't sell genetically modified produce or onions from England. Tonight, we eat leeks!

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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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Why Does the Supreme Court Have Nine Justices?

Front row, left to right: Stephen G. Breyer, Clarence Thomas, (Chief Justice) John G. Roberts, Jr., Ruth Bader Ginsburg, Samuel A. Alito. Back row: Neil M. Gorsuch, Sonia Sotomayor, Elena Kagan, Brett M. Kavanaugh.
Front row, left to right: Stephen G. Breyer, Clarence Thomas, (Chief Justice) John G. Roberts, Jr., Ruth Bader Ginsburg, Samuel A. Alito. Back row: Neil M. Gorsuch, Sonia Sotomayor, Elena Kagan, Brett M. Kavanaugh.
Fred Schilling, Collection of the Supreme Court of the United States // Public Domain

Some facets of the U.S. government—like presidential terms and post offices—were written into the original Constitution after (often lengthy) deliberations by the Founding Fathers. The number of Supreme Court justices was not one of those things.

The document did establish a Supreme Court, and it stated that the president should appoint its judges; it also mentioned that a “Chief Justice shall preside” if the president gets impeached. Since it was left up to Congress to work out the rest of the details, they passed the Judiciary Act of 1789, which outlined an entire court system and declared that the Supreme Court should comprise one chief justice and five associate justices. As History.com explains, they landed on six because the justices would have to preside over federal circuit courts, one of which was located in each state. Traveling wasn’t quick or easy in the horse-and-carriage days, so Congress wanted to minimize each justice’s jurisdiction. They split the courts into three regions, and assigned two justices to each region.

According to Maeva Marcus, director of the Institute for Constitutional History at George Washington University Law School, the even number of justices was a non-issue. “They never even thought about it, because all the judges were Federalists and they didn’t foresee great disagreement,” she told History.com. “Plus, you didn’t always have all six justices appearing at the Supreme Court for health and travel reasons.”

Over the next 80 years, the number of Supreme Court justices would fluctuate for two reasons: the addition of federal circuit courts, and presidents’ partisan motives. John Adams and his Federalist Congress reduced the number to five with the Judiciary Act of 1801, which they hoped would prevent Democratic-Republican Thomas Jefferson from getting to fill a seat after he took office that year. By the following year, Jefferson’s Congress had passed another judicial act that returned the number of justices to six, and they upped it to seven after forming another circuit court in 1807.

The nation grew significantly during the early 19th century, and Congress finally added two new circuit courts—and with them, two new Supreme Court seats—during Andrew Jackson’s presidential tenure in 1837. Republican Abraham Lincoln then briefly increased the number of justices to 10 in order to add another abolitionist vote, but Congress shrunk it to seven in 1866 to keep Andrew Johnson from filling seats with Democrats. As soon as Republican Ulysses S. Grant succeeded Johnson, Congress set the number back to nine, where it’s remained ever since.

Sketched portraits of the U.S. Supreme Court justices through 1897.Popular and Applied Graphic Art Print Filing Series, Library of Congress Prints and Photographs Division // No Known Restrictions on Publication

In 1911, Congress did away with circuit courts altogether, so the number of Supreme Court justices stopped being contingent upon their expansion (though each justice does still oversee a region to help with occasional tasks). As for presidents shifting the number to serve their own goals, it’s now looked down upon as “packing the court.” When Franklin D. Roosevelt tried to increase it to 15 in the 1930s to push his New Deal through the Supreme Court, the Senate opposed the bill by a whopping 70 to 20 votes.

In short, the depth of the Supreme Court’s bench changed a lot in America’s early years not only because the country was expanding, but also because the federal government was still testing out its system of checks and balances. And though presidents do still appoint justices based on their own political party, we’ve gotten used to the idea that the Supreme Court is, at least ideologically, supposed to be unbiased. If Congress and the president kept up the habit of adding and subtracting justices at will, it would tarnish this ideal.

“If Congress increases the size of the Supreme Court for transparently partisan political reasons, it would cement the idea the justices are little more than politicians in robes, and that the court is little more than an additional—and very powerful—arm through which partisan political power can be exercised,” Steve Vladeck, a professor at the University of Texas School of Law, wrote for NBC News. “Indeed, that Congress has not revisited the size of the court in 150 years is a powerful testament to just how ingrained the norm of nine has become—and how concerned different political constituencies have been at different times about preserving the court’s power.”

[h/t History.com]