Why Do Shells Sound Like the Ocean?

iStock
iStock

Kevin in Bentonville, Arkansas, wrote in to ask this question: "Why do you hear the ocean when you put a seashell up to your ear?"

All right, first things first: no matter how much it may sound like the rolling waves, it's not actually the ocean you're hearing in a shell.

Now that we've got that out of the way, what exactly is it that you're hearing? In a word, noise; the ambient noise that's being produced all around and inside you, which you normally don't hear or pay attention to because it's too quiet.

To amplify this noise so you can hear it clearly, you need a resonator. Want to make one on the cheap? Form an O shape with your mouth and flick your finger against your throat or cheek. You should hear a note. Make a smaller or larger O, or change the shape of your mouth, and you'll get different notes. Sort of like this. What you're doing here is letting your mouth fulfill its potential as a Helmholtz resonator, where sound is produced by air vibrating in a cavity with one opening. Different pitches can be coaxed out by changing the shape of the resonating cavity.

The seashell you're listening to—the inside of which has many hard, curved surfaces great for reflecting sound—is essentially doing the same thing you just did with your mouth. The ambient noise mentioned before—the air moving past and within the shell, the blood flowing through your head, the conversation going on in the next room—is resonating inside the cavity of the shell, being amplified and becoming clear enough for us to notice. Just like the various shapes we make with our mouths will produce different pitches, different sizes and shapes of shell sound different because different resonant chambers will amplify different frequencies.

The fact that all shells sound just a little bit like the ocean is purely coincidental. Holding any sort of Helmholtz resonator to your ear will produce a similar effect, whether that object is associated with the ocean or not. Put an empty glass over your ear or even cup your hand over it, and the sound you hear will be just about the same.

Fact-Checking Pottermore's Claim That Witches and Wizards Used Spells to 'Vanish' Their Waste Before Modern Plumbing

Warner Bros. All Rights Reserved. Harry Potter Publishing Rights/J.K.R.
Warner Bros. All Rights Reserved. Harry Potter Publishing Rights/J.K.R.

By now, you may have heard the peculiar explanation of how witches and wizards in J.K. Rowling’s universe relieved themselves before modern-day plumbing. As Entertainment Weekly reports, a section of the Pottermore website pertaining to the Chamber of Secrets entrance (which, if you recall, was in Moaning Myrtle’s bathroom) states that Hogwarts adopted plumbing in the 18th century. Before that, spells were cast to eliminate excrement—or perhaps blast it into another dimension.

“Hogwarts’ plumbing became more elaborate in the eighteenth century (this was a rare instance of wizards copying Muggles, because hitherto they simply relieved themselves wherever they stood, and vanished the evidence),” the site states in an essay by Rowling. This was initially revealed in 2015, but Pottermore's recent tweet on the subject has been causing a stink.

A lot of people aren’t satisfied with this unsavory explanation—"witches and wizards, some highly sophisticated beings who created complex magical governments and tamed the fiercest beasts, at one point just pooped themselves,” Entertainment laments—but it’s worth noting that the claim does pass a historical fact check of sorts.

According to Rowling, Hogwarts was founded in the year 990 C.E.—more than 600 years before Sir John Harington, the godson of Queen Elizabeth I and a distant relative of Game of Thrones star Kit Harington, invented the first flush toilet. Even though this technology existed in the 16th century, Harington only made two toilets: One for himself and one for his royal godmother. The first patented flush toilet didn’t arrive until 1775, thanks to a different design by watchmaker (and toilet inventor) Alexander Cummings. So the timing checks out.

Of course, people didn’t just pee themselves or pop a squat on the ground prior to working toilets, which is why so many people are baffled by Rowling’s explanation. Chamber pots and outhouses were used throughout much of human history, and members of the British ruling class had more luxurious arrangements. In the 16th century, King Henry VIII did his business atop a padded chair—covered in sheepskin, black velvet, and ribbons—with a chamber pot beneath it. However, male courtiers did sometimes do their business wherever they felt like it (palace stairwells were one popular location in France).

As for Hogwarts’ plumbing situation, it may sound like a gross and unnecessary detail, but it’s actually relevant to the story. According to a Pottermore essay penned by Rowling, the entrance to the Chamber of Secrets was nearly revealed when the school decided to build a bathroom on the site. However, a student and direct descendent of Slytherin named Corvinus Gaunt played a part in concealing its entrance—“even after newfangled plumbing had been placed on top of it.”

[h/t Entertainment Weekly]

Diagnosing the Home Alone Burglars' Injuries: A Professional Weighs In

20th Century Fox
20th Century Fox

By Lauren Hansen

Since its debut in 1990, Home Alone has become as much a part of the Christmas cinematic ritual as It's a Wonderful Life. But unlike that uplifting tale about the good of mankind, Home Alone tells a rather unsettling Christmas story of a precocious 8-year-old who, after accidentally being abandoned by his family, is forced to defend his home from two dimwitted burglars.

Kevin McCallister (Macaulay Culkin) turns his family's home into a veritable funhouse of torturous booby traps that the so-called Wet Bandits Marv (Daniel Stern) and Harry (Joe Pesci) hilariously stumble through, and the transformation of a suburban Chicago home into a relentless injury machine is nothing short of spectacular. But it does require quite a suspension of disbelief. Can a man really be hit square in the face with a steam iron and walk away unfazed? What kind of permanent physical damage would a blow torch to the head really do? To answer these questions and officially dissolve Home Alone's Hollywood magic, I spoke with my friend Dr. Ryan St. Clair of the Weill Cornell Medical College. Enjoy.

THE INJURY: BB GUN TO THE FOREHEAD

The Set-Up: Marv and Harry try to sneak into the McCallister home by sweet talking Kevin from the back door. Kevin, meanwhile, points his BB gun through the doggie door and directly at Harry's groin—and shoots. When Marv goes to investigate the source of Harry's pain, he is met by the same BB gun, which is fired at extremely close range to his forehead.

The Doctor's Diagnosis: "Classic air-powered projectile weapons typically have muzzle velocities of 350 feet per second or less. A BB fired at close range from such a weapon could break the skin, but will not penetrate the skull, and is unlikely to penetrate Harry's scrotum, especially through fabric."

THE INJURY: IRON TO THE FACE

The Set-Up: Thwarted by the BB gun at the back door, Marv runs around to the basement stairwell—which Kevin has deliberately iced. Once he has stumbled his way down into the dark basement, Marv grabs for what he thinks is the light bulb cord. It's actually a rope attached to a steam iron that is propped up on the laundry chute door. The heavy iron comes plummeting down and smacks Marv in the face.

The Doctor's Diagnosis: "Let's estimate the distance from the first floor to the basement at 15 feet, and assume the steam iron weighs 4 pounds. And note that the iron strikes Marv squarely in the mid-face. This is a serious impact, with enough force to fracture the bones surrounding the eyes. This is also known as a 'blowout fracture,' and can lead to serious disfigurement and debilitating double vision if not repaired properly."

THE INJURY: HANDLING A BURNING-HOT DOORKNOB

The Set-Up: While Marv is getting an iron to the face, Harry tries to enter the home through the front door. The first attempt doesn't go well, as the stocky burglar slips on the icy steps and falls to the ground, landing with a thud on his back. Easing up a second time with the help of the railing, Harry makes it to the front door, reaches for the doorknob—which we see is literally burning red—and grasps the searing handle, the pain of which forces him once again down the icy steps.

The Doctor's Diagnosis: "If this doorknob is glowing visibly red in the dark, it has been heated to about 751 degrees Fahrenheit, and Harry gives it a nice, strong, one- to two-second grip. By comparison, one second of contact with 155 degree water is enough to cause third degree burns. The temperature of that doorknob is not quite hot enough to cause Harry's hand to burst into flames, but it is not that far off ... Assuming Harry doesn't lose the hand completely, he will almost certainly have other serious complications, including a high risk for infection and 'contracture' in which resulting scar tissue seriously limits the flexibility and movement of the hand, rendering it less than 100 percent useful. Kevin has moved from 'defending his house' into sheer malice, in my opinion."

THE INJURY: A BLOWTORCH TO THE SCALP

The Set-Up: Unable to get through the front door, Harry returns to the back. He kicks his foot through the doggy door to disarm a potential BB gun threat, delicately taps at the doorknob to test its temperature, and, finding it cool, opens the back door—only to unknowingly arm a blowtorch that fires at the top of his head.

The Doctor's Diagnosis: "Harry has an interesting reaction to having a lit blowtorch aimed directly at his scalp. Rather than remove himself from danger, he keeps the top of his skull directly in the line of fire for about seven seconds. What was likely a simple second-degree skin burn is now a full thickness burn likely to cause necrosis of the calavarium (skull bone)." That means the skin and bone tissue on Harry's skull will be so damaged and rotted that his skull bone is essentially dying and will likely require a transplant.

THE INJURY: WALKING BAREFOOT ON CHRISTMAS TREE ORNAMENTS

The Set-Up: After surviving the iron to the face, getting his shoes and socks peeled off by tar, and stepping onto a 3-inch nail, Marv abandons the basement entrance and enters the home through a conveniently opened window. Without looking down, however, and still barefoot, Marv jumps in, putting his full weight on a dozen pointy ornaments littered on the wood floor.

The Doctor's Diagnosis: "Walking on ornaments seems pretty insignificant compared to everything else we've seen so far. If I was Marv, I'd be more concerned about my facial fractures."

THE INJURY: PAINT CAN TO THE FACE

The Set-Up: Although severely injured, both the burglars are finally inside the house, and have forgone their looting plan for one of revenge. Hearing the taunts of Kevin's pre-pubescent voice, they scamper into the foyer only to slip dramatically on scores of Micro Machines, landing, once again, on their backs. Kevin cruelly mocks them from the top step: "You guys give up yet? Or are you thirsty for more?" Marv and Harry scramble up the staircase, where they are met by a speeding paint can attached to a rope. Harry manages to duck and evade the first hit, but Marv gets a paint can square in the face. Harry continues up the stairs but is hit by a second paint can. Both burglars end up back on the ground floor.

The Doctor's Diagnosis: "Assuming the paint can is full (roughly 10 pounds) and the rope is 10 feet long, Marv and Harry each take a roughly 2 kilo-newton hit to the face. That is easily enough to fracture multiple facial bones, and is probably going to knock you out cold. Also, I wouldn't expect either of the Wet Bandits to walk away from this with all of their teeth."

THE INJURY: SHOVEL TO THE BACK OF THE HEAD

The Set-Up: Kevin eventually lures the Wet Bandits through his house of injurious horrors, across the street, and into a neighbor's house. But Marv and Harry have clued into the fact that following the little tyke has provided them nothing but pain. They enter the neighbor's house their own way and meet little Kevin at the top of the basement steps. They hang him by his sweater from a hook on the back of a door and outline all the ways in which they will pay him back for the pain he caused, beginning with biting "every one of these little fingers, one at a time." Just before Harry can take the first bite, Kevin's elderly neighbor saves the day, coming up behind the burglars and hitting each one over head with his shovel, knocking them out cold.

The Doctor's Diagnosis: "Seriously? At this point, Marv and Harry have both suffered potentially crippling hand and foot injuries. Harry has proved to be nearly impervious to burns, and both managed to retain consciousness after taking a flying paint can straight to the face. Suddenly, a frail elderly man appears and weakly slaps them in turn with a flimsy aluminum Home Depot snow shovel. And, somehow, this is too much for them, and they collapse. This movie was way more believable when I was 8."

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