Incredible Things You Probably Never Thought About

Why do we hiccup?

During a hiccup, the muscles we use to inhale contract while our vocal cords are slammed shut by the tongue and the roof of the mouth. There’s no discernible purpose for hiccups in humans, but a similar pattern of movement among amphibians is useful. When tadpoles are breathing underwater during a stage when they have both lungs and gills, they take in a mouthful of water, close the opening to the lungs, and then force the water out through their gills. In both humans and amphibians, the signal initiating hiccup-like activity comes from the brain stem.
Causes:

• Drinking carbonated beverages
• Drinking too much alcohol
• Eating too much
• Excitement or emotional stress
• Sudden temperature changes
• Swallowing air with chewing gum or sucking on candy

Why are school buses yellow?

The color is officially called “national school bus glossy yellow,” and it’s standard across the United States. Back in 1939, at a conference funded by the Rockefeller Foundation, transportation officials from all of the then 48 states agreed on a number of safety standards for school buses, including the color. Yellow is very visible, even in early morning or late-evening light, and black lettering on a yellow background is easy to read. It took until 1974 for all the school buses in the country to meet the standards.

Why do squirrels chase one another?

When they go on mad sprints up and down trees and across your yard and deck, they’re probably working out their hierarchy, according to Live Science. Squirrel expert Michael Steele of Wilkes University in Pennsylvania tells the website that the most common U.S. species—the Eastern gray squirrel—doesn’t tend to be territorial but does like to let everyone know who’s boss. Not too surprisingly, young squirrels also like to chase one another around for fun, just as puppies do.

How do birds know where to migrate?

Forty percent of bird species migrate every year, with some traveling tens of thousands of miles. (Arctic terns fly about 50,000 miles every year, from pole to pole.) Migrating birds can even find their destinations if researchers make them start from unusual locations, according to an article in the Conversation by Richard Holland, senior lecturer in animal cognition at Bangor University. How do they do it? Holland and his team published a study suggesting that some songbirds use a magnetic map to navigate long distances, but nobody knows how they can detect the Earth’s magnetic field. 

Why are there 13 in a baker’s dozen?

Bakers in medieval England are thought to have come up with the idea of tossing in an extra roll or loaf of bread to make sure their customers were happy. While 12 eggs are easy to quantify, baked goods can turn out all different sizes because of differences in how much the dough rises. Plus, many bakers didn’t have accurate scales to weigh their flour, according to Britannica. Being accused of cheating could result in punishment, including flogging, so bakers hedged their bets and included 13 (or sometimes 14) items to make sure nobody complained.

Why do we say “cheese” when we’re having our picture taken?

Saying the word cheese does make you pull your lips back and show your teeth, so if you’re trying to get a lot of people to at least approximate smiling at the same time, it’s a good start. The practice is mentioned in a 1943 Texas newspaper article, according to Today I Found Out.

Why do jeans have those tiny pockets?

Those tiny pockets in your jeans seem pretty pointless, but they actually served a purpose back in the 1800s. It’s called a watch pocket because it was originally intended as a safe place for men to store their pocket watches. It dates back to Levi’s first-ever pair of jeans, which hit the market in 1879. 

Why do passports only come in four colors?

The International Civil Aviation Organization requires that all countries use a specific typeface, type size, and font for all official documents, including passports. Even though there are a lot of requirements that passports have to meet, the specific color isn’t actually one of them. But most countries choose to use simple dark shades of red, green, or blue because they look more official and they hide dirt and wear.

Why do car windows have little black dots?

The little black dots on your car’s windshield and windows, and the black rims that surround them, aren’t just there for decoration. The dots date all the way back to the ’50s, when car manufacturers used adhesive to hold car windows in place rather than metal trim.

The black trim around the windows  and the black dots are painted onto the glass to hide the not very appealing look of the adhesive. The rims are actually baked into the window, so they hold the glue and window in place. The dots serve as an aesthetically pleasing transition from the thick black line to the transparent window. They aren’t just there to look nice though.

They help provide temperature control. When the glass is bent to fit into the frame of the windshield, it’s heated up. The black-painted glass heats up faster than the rest, and the dots help to distribute the heat more evenly and keep the glass from warping. 

Why do my fingers get wrinkly when I’m swimming?

It may seem as if your skin is absorbing extra water during a soak in the pool or bathtub, but that’s not the case. Researchers have known since the 1930s that people with nerve damage in their fingers don’t prune up the way everyone else does. In other words, wrinkly fingers don’t happen through osmosis, according to Scientific American.

Instead, it’s caused by blood vessels below the skin that constrict, which seems to have the evolutionary advantage of making it easier for us to pick up wet objects. For a 2013 study published in Biology Letters, scientists found that subjects with wrinkled fingers were faster at picking up submerged marbles (but didn’t do any better at picking up dry objects) than those with unwrinkled fingers.

Why do squirrels chase one another?

When they go on mad sprints up and down trees and across your yard and deck, they’re probably working out their hierarchy, according to Live Science. Squirrel expert Michael Steele of Wilkes University in Pennsylvania tells the website that the most common U.S. species the Eastern gray squirrel doesn’t tend to be territorial but does like to let everyone know who’s boss. Not too surprisingly, young squirrels also like to chase one another around for fun, just as puppies do.