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.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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.

Sign Up Today: Get exclusive deals, product news, reviews, and more with the Mental Floss Smart Shopping newsletter!

Why Do We Have Daylight Saving Time?

Patrick Daxenbichler/iStock via Getty Images
Patrick Daxenbichler/iStock via Getty Images

As you drag your time-confused body out of bed at what seems like a shockingly late hour next week, you might find yourself wondering why on Earth we even have Daylight Saving Time.

Though Benjamin Franklin was mostly joking when he suggested it as a money-saving tactic in a satirical essay from 1784, others who later proposed the idea were totally serious. In 1895, entomologist George Vernon Hudson pitched it to the Royal Society in New Zealand as a way to prolong daylight for bug-hunting purposes, and William Willett spent the early 1900s lobbying British Parliament to adopt an 80-minute time jump in April; neither man was successful.

During World War I, however, the need to conserve energy—which, at the time, chiefly came from coal—increased, and Germany was the first to give Daylight Saving Time the green light in 1916. Britain and other European countries quickly followed suit, and the U.S. entered the game in 1918. The practice was dropped almost everywhere after the war, but it was widely resurrected just a few decades later during World War II.

After that war ended, the U.S. abandoned DST yet again—sort of. Without any official legislation, the country devolved into a jumble of conflicting practices. According to History.com, Iowa had 23 different pairs of start and end dates for DST in 1965, while other areas of the country didn’t observe DST at all.

In 1966, Congress put an end to the chaos by passing the Uniform Time Act, which specified that DST would begin at 2:00 a.m. on the last Sunday in April, and end at the same time on the last Sunday in October. (The Energy Policy Act of 2005 extended DST by shifting these dates to the second Sunday in March and the first Sunday in November.) It didn’t require that all states and territories actually observe DST, and some of them didn’t—Arizona and Hawaii still don’t.

Throughout its long, lurching history, the supposed merits of Daylight Saving Time have always been about cutting down on electricity usage and conserving energy in general. But, as Live Science reports, experts disagree on whether this actually works. Some studies suggest that while the extra daylight hour might decrease lighting-related electricity use, it also means people could be keeping their air conditioners running for long enough that it increases the overall usage of electricity.

If your extended night’s sleep seems to have left you with a little extra time on your hands, see how DST affects your part of the country here.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.