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Australian Toilets Don't Flush Backwards Because of the Coriolis Effect

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Toilet image via Shutterstock

File under "News to Me": you know that old story about how northern hemisphere toilets flush counter-clockwise, and southern hemisphere toilets (and buckets, drains, and such) flush clockwise, due to the Coriolis effect? It's bogus! Today I learned that while the Coriolis effect is significant for hurricanes, it's not strong enough to make toilets flush in different directions at different points on the Earth. The real cause of "backwards"-flushing toilets is just that the water jets point in the opposite direction. Mind blown. (Mind blown even more because this was the inciting event on a Simpsons episode, and everybody knows cartoons are never wrong.)

Let's Talk Science

So there is indeed a Coriolis effect, and we see it on grand scales -- hurricanes in different hemispheres tend to rotate in different directions, because the underlying Earth is spinning, and the effect is exaggerated as you move farther from the equator. This Penn State science page by Professor of Meteorology Alistair B. Fraser explains:

On the scale of hurricanes and large mid-latitude storms, the Coriolis force causes the air to rotate around a low pressure center in a cyclonic direction. Indeed, the term cyclonic not only means that the fluid (air or water) rotates in the same direction as the underlying Earth, but also that the rotation of the fluid is due to the rotation of the Earth. Thus, the air flowing around a hurricane spins counter-clockwise in the northern hemisphere, and clockwise in the southern hemisphere (as does the Earth, itself). In both hemispheres, this rotation is deemed cyclonic. If the Earth did not rotate, the air would flow directly in towards the low pressure center, but on a spinning Earth, the Coriolis force causes that air to be deviated with the result that it travels around the low pressure center.

So it works on large scales. But on small scales (like in your toilet, sink, or bucket), the rotation of the Earth itself (at a decidedly pokey rate of one rotation per day) is much weaker than other forces -- like the force of water jets in a toilet, or the force of water hitting slopes in a sink.

The Pole to Pole Problem

In tracking down where this drain-direction myth originated and how it got so firmly lodged in the heads of people like me, many sources discuss the (otherwise awesome) Michael Palin documentary Pole to Pole, in which Palin visits the equator in Kenya and observes a tourist trap in which a man "demonstrates" (via fakery) the draining of water in different ways on the equator itself, and just north and south of it. Palin doesn't point out that it's fake. I remember seeing this documentary when it came out, and it may be where I picked up the notion -- it seems like such an appealing demonstration of science, such an "ah-ha!" moment that of course the rotation of the Earth should cause such changes in draining water! We're all tiny ants on a huge spinning globe! What wonders! Sadly, it's BS. Again, Fraser has a good write-up; here's a snippet:

[T]he faker must be forcing the rotation by other means, and by a sufficiently unobtrusive way that the busloads of tourists do not spot the means. Indeed, a colleague of mine, who witnessed the performance first hand and knew it was a cheat, was not able to spot how the fraud was perpetrated. (It is an interesting sidelight that when back on the bus, he informed his fellow tourists that they had just witnessed fakery --- the Earth did not cause the rotation they had just seen --- there was widespread disappointment. The tourists preferred the fantasy to the reality.)

Fraser proceeds to explain how you can fake it yourself.

The Plot Thickens

According to various sources, it is possible to demonstrate a Coriolis effect on water on a small scale, but only under extremely controlled circumstances -- involving predictably shaped water vessels, long periods of time of waiting for water to become as still as possible, carefully removing a stopper in the bottom of the vessel without adding spin, and other such crazy stuff. But in your typical toilet or sink, the Coriolis force is so small as to be undetectable relative to other forces. Even holding a bowl of water and turning around introduces sufficient spin to get things going in one direction or another.

A Fun Experiment

Go to your bathroom now and observe water going down the drain -- any drain you want. Depending on the efficiency of your plumbing, you may need to stop up the drain, fill the basin, then unplug it and wait. (It might also help to have something lightweight floating in there, to mark any motion -- a few bits of tissue may work, or a matchstick or two.) Observe whether the draining water forms a clockwise or counter-clockwise spiral. Go ahead, I'll wait. Now check all the other drains you can find. Do they match? In my (admittedly unscientific) testing just now, one sink drained clockwise, the other counter-clockwise, one didn't have an easily observable spin (it's small), and the toilet was also counter-clockwise, clearly due to the position of its water jets. Well. There you go: science in action.

(Via Steven Frank, via Snopes. Note that we covered this topic back in 2007 as well.)

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AMNH // R. Mickens
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science
What It’s Like to Write an Opera About Dinosaurs
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AMNH // R. Mickens

There are many challenges that face those writing the lyrics to operas, but figuring out what can rhyme with dinosaur names isn’t often one of them. But wrangling multisyllabic, Latin- and Greek-derived names of prehistoric creatures into verse was an integral part of Eric Einhorn’s job as the librettist behind Rhoda and the Fossil Hunt, a new, family-friendly opera currently running at the American Museum of Natural History in New York City.

Created by On Site Opera, which puts on operas in unusual places (like Madame Tussauds Wax Museum) across New York City, in conjunction with the Lyric Opera of Chicago and the Pittsburgh Opera, Rhoda and the Fossil Hunt follows the true story of Rhoda Knight and her grandfather, the famous paleoartist Charles R. Knight.

Knight worked as a freelance artist for the American Museum of Natural History from 1896 until his death in 1953, creating images of extinct species that paved the way for how we imagine dinosaurs even now. He studied with taxidermists and paleontology experts and was one of the first to paint dinosaurs as flesh-and-blood creatures in natural habitats rather than fantastical monsters, studying their bones and creating sculptural models to make his renderings as accurate as contemporary science made possible.

In the 20-minute opera, singers move around the museum’s Hall of Saurischian Dinosaurs, performing among skeletons and even some paintings by Knight himself. Einhorn, who also serves as the director of On Site Opera and stage director for the opera, wrote the libretto based on stories about the real-life Rhoda—who now goes by Rhoda Knight Kalt—whom he met with frequently during the development process.

Soprano Jennifer Zetland (Rhoda) sings in front of a dinosaur skeleton at the American Museum of Natural History.
AMNH // R. Mickens

“I spent a lot of time with Rhoda just talking about her childhood,” he tells Mental Floss, gathering anecdotes that could be worked into the opera. “She tells this great story of being in the museum when they were unpacking the wooly mammoth,” he says. "And she was just there, because her grandfather was there. It's being at the foot of greatness and not even realizing it until later.”

But there was one aspect of Rhoda’s childhood that proved to be a challenge in terms of turning her story into a performance. “Unfortunately, she was a really well-behaved kid,” Einhorn says. “And that doesn't really make for a good opera.”

Knight Kalt, who attended the opera’s dress rehearsal, explains that she knew at the time that if she misbehaved, she wouldn’t be allowed back. “I knew that the only way I could be with my grandfather was if I was very quiet,” she says. “Sometimes he would stand for an hour and a half discussing a fossil bone and how he could bring that alive … if I had interrupted then I couldn't meet him [at the museum anymore].”

Though Knight Kalt was never an artist herself, in the fictionalized version of her childhood (which takes place when Rhoda is 8), she looks around the museum for the missing bones of the dinosaur Deinocheirus so that her grandfather can draw them. The Late Cretaceous dino, first discovered in 1965, almost didn't make it into the show, though. In the first draft of the libretto, the dinosaur Rhoda is searching for in the museum was a relatively new dinosaur species found in China and first unveiled in 2015—zhenyuanlong suni—but the five-syllable name proved impossible to rhyme or sing.

Rhoda Knight Kalt stands next to the head of a dinosaur.
Rhoda Knight Kalt
Shaunacy Ferro

But Einhorn wanted to feature a real dinosaur discovery in the opera. A paleontologist at the museum, Carl Mehling, suggested Deinocheirus. “There are two arms hanging right over there,” Einhorn says, gesturing across the Hall of Saurischian Dinosaurs, “and until [recently] the arms were the only things that had ever been discovered about Deinocheirus.” Tying the opera back to an actual specimen in the museum—one only a few feet away from where the opera would be staged—opened up a whole new set of possibilities, both lyrically and otherwise. “Once we ironed that out, we knew we had good science and better rhyming words.”

As for Knight Kalt, she says the experience of watching her childhood unfold in operatic form was a little weird. “The whole story makes me laugh,” she says. But it was also a perfectly appropriate way to honor her grandfather. “He used to sing while he was painting,” she says. “He loved the opera.”

Performances of Rhoda and the Fossil Hunt will be performed at the American Museum of Natural History on Fridays, Saturdays, and Sundays until October 15. Performances are free with museum admission, but require a reservation. The opera will later travel to the Lyric Opera of Chicago and the Pittsburgh Opera.

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iStock
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Animals
11 Buoyant Facts About Humpback Whales
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iStock

Humpback whales are some of the most intelligent animals on the planet. Hunted almost to extinction during the 19th and early 20th centuries, their populations are slowly recovering, and now they’re a favorite sight for whale-watchers. Here are 11 facts you might not have known about the mysterious marine giants, who are known for their acrobatics and for sidling right up alongside boats to get a good look at their human observers.

1. THEY’RE LONGER THAN A SCHOOL BUS.

North American school buses max out at about 45 feet long. Female humpback whales—which are larger than males—can be up to 60 feet long, and their pectoral fins alone can be 15 feet long. At birth, humpbacks weigh around 1 ton, doubling in size during their first year of life and eventually reaching up to 40 tons.

2. THEY HAVE HUGE MOUTHS.

In keeping with the rest of their bodies, their mouths are huge—their tongue alone is the size of a small car. But the opening to their throat is only about the size of a grapefruit, according to the Hawaiian Islands Humpback Whale National Marine Sanctuary, so they can’t swallow large prey. Instead, they eat krill, small fish, and plankton. They can eat up to a ton of food per day, according to the 2015 documentary Humpback Whales.

3. THOSE BUMPS ARE HAIR FOLLICLES.

Each of the distinctive bumps along a humpback’s head holds a single hair that the whale uses to sense the environment around it. These hairs help the whale glean information about water temperature and quality.

4. THEIR FLUKES ARE LIKE FINGERPRINTS.

Like human fingerprints, humpback tails can be used to identify individuals. The pigmentation and scarring on their flukes is unique, and scientists document these markings to keep track of certain whales that they see repeatedly during their research trips.

5. THEY LIVE A LONG TIME, BUT NOT AS LONG AS MANY OTHER WHALES.

Most humpback whales make it into their 60s, but scientists estimate that they may live up to 80 years. Still, that’s nothing compared to bowhead whales, a species whose oldest known individuals have lived to be 200 years old.

6. THEY HAVE THE LONGEST MIGRATIONS OF ANY MAMMAL.

Each year, humpbacks migrate from their feeding grounds in cold waters toward warm breeding areas—Alaskan whales head to Hawaii, while Californian whales head to Mexico and Costa Rica, and Australian whales migrate to the Southern Ocean. These biannual journeys can involve distances of up to 5000 miles, which is officially the longest known migration of any mammal on earth.

The fastest documented migration of a humpback whale was observed in 1988, when a humpback traveled from Sitka, Alaska to to Hawaii in just 39 days—or possibly less, depending on how soon it left Alaskan waters after the researchers sighted it the first time [PDF]. That’s a journey of about 2750 miles point to point.

7. THEY HAVE BEEN KNOWN TO DEFEND OTHER SPECIES FROM ORCAS.

In 2009, marine ecologist Robert Pitman watched two humpback whales rescue a seal from a group of orcas that were pursuing it. The seal ended up on one of the humpbacks’ chests, and when it began to fall off, the whale even nudged it back on with a flipper, indicating that it was an intentional act of altruism. Though it’s not entirely clear why they would do so, it appears to be an offensive response on the part of the humpbacks, who may intervene whenever they hear killer whales fighting, whether one of their own is involved or not.

8. ONLY THE MALES SING.

Their songs may have made the species famous, but not every humpback sings. It’s strictly a male behavior, and plays an important part in courtship displays. There’s plenty of mystery that still surrounds the science of whale songs, but in 2013, researchers discovered that it’s a group activity that involves even sexually immature males. Both young and mature whales sing in chorus, giving the immature whales a lesson in singing and courtship behavior, and helping older whales amplify their songs to draw females to the area from afar. Other research has found that these songs change over times, and whales learn them much like a human learns a new song, bit by bit.

9. BREACHING IS LIKE YELLING

Though humpbacks are famous for their songs, that’s not the only way they communicate. Scientists only recently discovered that breaching—when whales jump up into the air, crashing back down into the water—is a way to keep in touch with far-away friends. Humpbacks leap higher and more often than other whales, and while spectacular to witness, the moves come at a cost: It takes a lot of energy, especially when the whales are fasting. But after 200 hours observing humpbacks migrating past the Australian coast, a team from the University of Queensland found that the whales were more likely to breach when the nearest group of other humpbacks was more than two and a half miles away, and that they were more likely to do so when it was windy out. It appears that breaching is a way to communicate over long distances when there is a lot of competing noise.

10. THEIR SONGS ARE INCREDIBLY COMPLEX …

Humpback songs aren’t just showy. They have their own grammar, and their songs are hierarchical, like sentences. In human language, this means that the meaning of sentences depends on the clauses within them and the words within them. In 2006, mathematical analysis found that humpbacks use phrases, too. And they remix their tunes, too, tweaking them and changing them over time, often combining new and old melodies. Humpback songs have even been visualized as sheet music.

11. … AND HELPED END WHALING.

Researchers estimate [PDF] that prior to the whaling boom of the 19th and 20th centuries, there were around 112,000 humpbacks in the North Atlantic alone, but that by the time commercial whaling was banned in the region in 1955, there were less than 1000 individuals left. Between 1947 and the 1970s, the USSR alone killed an estimated 338,000 humpbacks, falsifying data it was required to submit to the International Convention for the Regulation of Whaling to disguise the illegal magnitude of its hunting operation. It has been called “one of the greatest environmental crimes of the 20th century.”

While the populations have grown and humpbacks have been taken off the endangered species list, some estimates put the worldwide humpback population at only 40 percent of what it was before the whaling era. Whaling was banned throughout the rest of the world in 1966, though Norway, Iceland, and Japan still practice it.

Roger Payne, one of the scientists who first discovered that humpbacks sing songs, later became instrumental in pushing to protect the species in the 1960s. In 1970, he released his recording of humpback songs as a record, which remains the best-selling nature recording in history. In 1972, the songs were played at a Greenpeace meeting, and ended up galvanizing a new movement: Save the Whales. “It certainly was a huge factor in convincing us that the whales were an intelligent species here on planet Earth and actually made music, made art, created an aesthetic,” as former Greenpeace director Rex Weyler told NPR in 2014. The campaign gained traction with other organizations, too, and helped lead to the International Whaling Commission’s 1982 whaling ban.

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