Learn about the mystery of why your shower curtain will randomly cling to you; whether masks affect our emotional development; and why humans perk up their ears.
Learn about the "shower-curtain effect," the mystery of why your shower curtain will randomly cling to you; whether masks affect our emotional development; and why humans perk up their ears.
No One Knows Why the Shower Curtain Will Randomly Cling to You by Joanie Faletto
Do masks affect our emotional development? by Ashley Hamer (Listener question from Nate)
Humans perk up their ears, too by Kelsey Donk
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Find episode transcript here: https://curiosity-daily-4e53644e.simplecast.com/episodes/do-masks-stunt-emotional-development-plus-human-ears-perk-up-too-and-why-your-shower-curtain-clings-to-you
CODY: Hi! You’re about to get smarter in just a few minutes with Curiosity Daily from curiosity-dot-com. I’m Cody Gough.
ASHLEY: And I’m Ashley Hamer. Today, you’ll learn about the mystery of why your shower curtain will randomly cling to you. Then, we’ll answer a listener question about whether masks affect our emotional development. You’ll also learn about why humans perk up their ears.
CODY: Let’s satisfy some curiosity.
Unless you’ve got a lot of open windows, bathrooms generally don't experience random gusts of wind. AND YET! You’ve probably had that eerie experience where the shower curtain randomly reaches out and clings to you. Why does this happen? Spoiler alert: WE DON’T KNOW! A scientific explanation has eluded physicists for years. No one knows exactly what causes the so-called “shower-curtain effect.” But you’re here to learn what we know, not what we don’t know. So let’s talk about a couple theories that have been proposed explain the phenomenon.
The first theory is that the hot air from the shower rises, so colder air from outside the shower rushes in to fill the void. That pushes the curtain right into your damp leg. Definitely an interesting theory, and one you could probably test by taking an ice-cold shower instead of a hot one. Welp, turns out someone actually did that, and the curtain still clung to them. Next!
Another popular guess is Bernoulli's principle [ber-NEW-lee]. This basically states that the movement of the water causes movement of the air in the shower, making the curtain drift inwards. But at least one scientist points out that Bernoulli’s principle doesn’t apply to droplets like the spray of your showerhead. Still no dice.
The next theory relies on the Coanda effect [KWAN-dah], which you’ve seen if you've ever held a spoon upright under a running faucet and seen the water bend. If you release your grip on the spoon a bit, you'll see that the spoon gravitates toward the water — not away from it. That might be what’s happening when the water hits the shower curtain and the curtain is pulled inward.
And lastly; it may happen due to a vortex. That’s according to engineer David Schmidt, who won an Ig Nobel Prize for this answer. He created a computer model of how the spray from a showerhead moves air inside the shower, creating a horizontal vortex. You can imagine the vortex sort of like a jar rolling on its side, drawing the shower curtain along with its motion as it rolls.
Despite the fact that Schmidt posed his theory about 20 years ago, scientists still haven’t done the research to confirm it. That’s fair — scientists probably have bigger fish to fry. For now, have fun trying to avoid hugs from your shower curtain. They can be so clingy.
We got a voicemail from Nate in South Carolina. Take a listen!
Great question, Nate. While it’s too soon to say what wearing masks during the coronavirus pandemic will do to children’s emotional development, we do have some hints from other types of research. Like, we know a good amount about emotional development in children who are born blind. While scientists used to think that babies learn facial expressions from their parents during their first months and years of life, recent research shows that blind children who don’t have that option still produce very similar facial expressions to sighted kids, even at a very young age. That suggests that emotional development may not rely as much on facial expressions as you might think.
In fact, when it comes to decoding emotion, studies show that the voice may be even more important than the face. In 1995, psychology professor Richard Wiseman carried out one of the U.K.'s largest-ever psychology experiments. And he found that audio-only listeners were able to detect when a person lied more than 73 percent of the time, versus 64 percent for newspaper readers and 52 percent for television viewers. In 2017, a Yale study that asked people to have conversations in either a lit or pitch-black room found that people in the pitch-black room were better at rating their conversation partners’ emotions. You can get a ton of emotional information without even looking at a person’s face.
But even when you do judge emotion from a person’s face, remember that the masks we’re wearing only cover the mouth and nose — our eyes are still exposed. It turns out that judging emotion from the mouth is more of a cultural phenomenon than a biological one. In Eastern cultures, the eyes are more important emotional cues than the mouth. Studies even suggest that people who look to the eyes to judge whether a smile is real or fake are more accurate than people who look at the mouth. And if you really want to test how well we can spot emotion with a mask on, just look at Muslim women who wear the niqab [nuh-KAAB] — that veil that covers everything but the eyes. A 2012 study found that people could accurately judge nearly every emotion displayed by a woman wearing a niqab.
So while we don’t have long-term data on what masks are doing to children’s emotional development, my hunch is that the effects aren’t too troubling. We convey emotion in a lot of ways, whether we’re showing our mouths or not. Thanks for your question, Nate! If you have a question, send it in to podcast at curiosity dot com or leave us a voicemail at 312-596-5208.
You know how dogs and cats will perk up their ears when they hear a new sound? Well, a recent study shows that humans actually do that, too! So when we tell children to “perk up their ears” to pay attention to something, they actually do! Cute, right?
If you didn’t know your ears could move around, I totally understand. This is the first time it’s ever been demonstrated, and the movements are tiny, involuntary, and totally unconscious. But they’re there. When we hear a new sound, our ear muscles adjust just a little bit.
This discovery came from a research team at Saarland University in Germany. They figured this out by first attaching sensors to the skin on and around people’s ears. If there was any muscle activity in these areas, the sensors could detect it.
Next, they performed two experiments.To see how the ears react to novel sounds, they had participants read a boring essay while they played random noises from different speakers positioned all around the room. To see what happens when people really focus on a sound, they told participants to listen to a short story coming from a speaker by one ear while ignoring a competing story coming from a speaker by the other.
The same thing happened in both experiments: the sensors detected tiny muscle movements in the ear closest to the sound. But the muscle movements were a little different. In the novel-sound experiment, the ear folded back ever so slightly. In the focus experiment, the whole ear raised up a tiny bit.
The movements could actually be caught on a high-definition video recording, as long as they used motion magnification.
The researchers say it’s very likely that this electrical movement is a ‘neural fossil’ in our brains from our primate ancestors. About 25 million years ago, the muscles responsible for orienting the ear became vestigial, or basically useless to us. But this study shows that this part of our ears still remembers how to move, the way dogs’ and cats’ ears do.
This isn’t just a cool discovery about how the human body works. The researchers hope this could also lead to better hearing aids. If a hearing aid could sense which direction a wearer was trying to focus their ears, it might be able to amplify the sound they wanted to hear. Pretty cool, right?
So the next time the doorbell rings, remember it’s not just your pet’s ears that’ll perk up. You can’t see it, but yours will do it, too. [ad lib]
Leave us a voicemail at 312-596-5208!
CODY: Before we recap what we learned today, here’s a sneak peek at what you’ll hear next week on Curiosity Daily.
ASHLEY: Next week, you’ll learn about the real reason for pregnancy cravings;
Why speedy raindrops don’t damage delicate insect wings;
How blind people are able to describe what animals look like;
Why ancient Greek temples were purposely built over fault lines;
And more! Okay, so now, let’s recap what we learned today.
[ad lib optional]
CODY: Today’s stories were written by Joanie Faletto, Ashley Hamer, and Kelsey Donk, and edited by Ashley Hamer, who’s the managing editor for Curiosity Daily.
ASHLEY: Scriptwriting was by Cody Gough and Sonja Hodgen. Today’s episode was edited by Cody Gough and Natalia Reagan. Curiosity Daily is produced by Cody Gough.
CODY: Have a great weekend, and join us again Monday to learn something new in just a few minutes.
ASHLEY: And until then, stay curious!