Why Does My Shower Curtain Liner Attack Me?

iStock
iStock

For most of us, showers are a time to block out external stimuli and enjoy a moment to ourselves. The blissful monotony can often lead to creative inspiration or new ideas. Celebrated screenwriter Aaron Sorkin once said he takes up to six showers a day to help unblock his mind and resolve story problems.

But not all showers can make us part of the wealthy Hollywood elite. Some showers can become exercises in dread and frustration. We’re referring to the persistent attack of the shower curtain liner.

Liners have a tendency to billow inward during showers, enveloping themselves around our calves and forcing us to swat them away. As problems, go, it’s fairly innocuous. But that doesn’t mean science hasn’t tried to understand the physics behind the phenomenon.

Back in 1938, Popular Science theorized that liners were behaving badly as a result of air currents. When hot air from the warm water rises, cold air around the tub seeks to replace it, causing the liner—which is in between—to grow agitated. This explanation seemed to satisfy people for a while, until someone pointed out that the liners tend to move even during a cold shower.

Others believed the liner was acting as a result of Bernoulli's principle, which states that air pressure around fluid decreases when the fluid is moving quickly. With a difference in air pressure inside and outside the tub, the liner will move.

In 2001, someone finally had the means and motivation to examine this theory more closely. David Schmidt, an assistant professor at the University of Massachusetts Amherst, used computer software developed to examine fluid spray to assist in diesel and aircraft engines to put Bernoulli's theory to the test. This being 2001, it took his home PC two weeks to run the simulation, which Schmidt programmed to replicate a typical shower (rod, curtain, liner, shower head).

Schmidt found that the shower spray created a vortex with a low-pressure region—a little like the center of a cyclone. That region is what “sucks” the liner inward. Despite the relative calm of a shower, the simulation indicated that you’re basically in the eye of a very low-level storm.

For more answers, Schmidt would probably have to consider overseeing a real-world model, but he said he doesn’t have the time or inclination to take the whole shower cyclone science thing to the next level.

That’s not quite the end of the story, though. In 2007, physics author Peter Eastwell tinkered with a shower set-up and noted that the cyclone effect was more pronounced in hotter than cooler water, and that factors like the distance of the liner from the spray affected the liner’s movement.

Clearly, more work needs to be done on this important issue. Until then, using a heavier liner or attaching weights to the bottom can prevent billowing. Alternately, you could just install a shower door. Aaron Sorkin probably has one.

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How and Why Did Silent Letters Emerge in English?

iStock/Bychykhin_Olexandr
iStock/Bychykhin_Olexandr

Kory Stamper:

The easy answer is “"because English can’t leave well enough alone."

When we first started speaking English around 600 AD, it was totally phonetic: every letter had a sound, and we sounded every letter in a word. But English—and England itself—were influenced quite a bit by the French, who conquered the island in 1066 and held it for a long time. And then later by Dutch and Flemish printers, who were basically the main publishers in England for a solid two centuries, and then by further trading contact with just about every continent on the planet. And while we’re shaking hands and stealing language from every single people-group we meet, different parts of the language started changing at uneven rates.

By the 1400s, English started to lose its phonetic-ness: the way we articulated vowels in words like “loud” changed slowly but dramatically, and that had an effect on the rest of the word. (This is called “The Great Vowel Shift,” and it took place over a few hundred years.) Somewhere in the middle of the GVS, though, English spelling became fixed primarily because of the printing press and the easy distribution/availability of printed materials. In short: we have silent letters because the spelling of words stopped changing to match their pronunciations.

This post originally appeared on Quora. Click here to view.

What’s the Origin of Jack-O’-Lanterns?

iStock/matejmo
iStock/matejmo

The term "jack-o'-lantern" was first applied to people, not pumpkins. As far back as 1663, the term meant a man with a lantern, or a night watchman. Just a decade or so later, it began to be used to refer to the mysterious lights sometimes seen at night over bogs, swamps, and marshes.

These ghost lights—variously called  jack-o’-lanterns, hinkypunks, hobby lanterns, corpse candles, fairy lights, will-o'-the-wisps, and fool's fire—are created when gases from decomposing plant matter ignite as they come into contact with electricity or heat or as they oxidize. For centuries before this scientific explanation was known, people told stories to explain the mysterious lights. In Ireland, dating as far back as the 1500s, those stories often revolved around a guy named Jack.

LEGEND HAS IT

As the story goes, Stingy Jack—often described as a blacksmith—invited the devil to join him for a drink. Stingy Jack didn't want to pay for the drinks from his own pocket, and convinced the devil to turn himself into a coin that could be used to settle the tab. The devil did so, but Jack skipped out on the bill and kept the devil-coin in his pocket with a silver cross so that the devil couldn’t shift back to his original form. Jack eventually let the devil loose, but made him promise that he wouldn’t seek revenge on Jack, and wouldn’t claim his soul when he died.

Later, Jack irked the devil again by convincing him to climb up a tree to pick some fruit, then carved a cross in the trunk so that the devil couldn’t climb back down (apparently, the devil is a sucker). Jack freed him again, on the condition that the devil once again not take revenge and not claim Jack’s soul.

When Stingy Jack eventually died, God would not allow him into heaven, and the devil, keeping his word, rejected Jack’s soul at the gates of hell. Instead, the devil gave him a single burning coal to light his way and sent him off into the night to “find his own hell.” Jack put the coal into a carved-out turnip and has supposedly been roaming the earth with it ever since. In Ireland, the ghost lights seen in the swamps were said to be Jack’s improvised lantern moving about as his restless soul wandered the countryside. He and the lights were dubbed "Jack of the Lantern," or "Jack O'Lantern."

OLD TALE, NEW TRADITIONS

The legend immigrated to the new world with the Irish, and it collided with another old world tradition and a new world crop. Making vegetable lanterns was a tradition of the British Isles, and carved-out turnips, beets, and potatoes were stuffed with coal, wood embers, or candles as impromptu lanterns to celebrate the fall harvest. As a prank, kids would sometimes wander off the road with a glowing veggie to trick their friends and travelers into thinking they were Stingy Jack or another lost soul. In America, pumpkins were easy enough to come by and good for carving, and got absorbed both into the carved lantern tradition and the associated prank. Over time, kids refined the prank and began carving crude faces into the pumpkins to kick up the fright factor and make the lanterns look like disembodied heads. By the mid-1800s, Stingy Jack’s nickname was applied to the prank pumpkin lanterns that echoed his own lamp, and the pumpkin jack-o’-lantern got its name.

Toward the end of the 19th century, jack-o’-lanterns went from just a trick to a standard seasonal decoration, including at a high-profile 1892 Halloween party hosted by the mayor of Atlanta. In one of the earliest instances of the jack-o’-lantern as Halloween decor, the mayor’s wife had several pumpkins—lit from within and carved with faces—placed around the party, ending Jack O’Lantern’s days of wandering, and beginning his yearly reign over America’s windowsills and front porches.

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