There’s a video on YouTube, filmed back in 2019, where 100 random people try to whistle on camera. About half of them fail, often spectacularly. But partway through, the video flashes through the 50 or so who succeed, and something interesting jumps out: at a glance, every single one of them appea rs to be making the identical shape with their mouth. Look closely, and the shape is surprisingly specific. The lips pull back slightly at the corners, rather than pucker forward. A small, round opening is left in the middle: It’s closer to the width of a pencil than the wide “O” most people imagine. All of this raises an obvious question: If the ability to whistle really does require making a specific shape with your mouth, why can’t everyone seem to figure it out? And more to the point: Can some people truly, genuinely not whistle, no matter how hard they try? According to Francisco Ruiz, a professor of mechanical engineering at the Illinois Institute of Technology who studies the acoustics of whistling, true anatomical impossibility is rare. For most people, he says, it’s simply a matter of practice. “It’s more like riding a bicycle,” he says. “You fall many times, and finally you get it.” Whistling requires making a very specific shape with your mouth. Video: 100 People Try to Whistle | Keep It 100, Cut The real reasons some people can’t whistle For a small number of people, certain physical conditions really do make whistling impossible, no matter how hard they try. “You need to get your lip geometry right, and then you need to get the geometry of your tongue against your palate right,” Ruiz says. “If you have somebody with a cleft palate [a congenital condition where the roof of the mouth doesn’t fully close], they just won’t be able to whistle, because they won’t be able to make that constriction [the narrow gap where air passes] correctly.” If, like me, you’re a little horrified at the idea that something as fun as whistling involves “geometry,” don’t worry: Nobody’s handing you a protractor. Your mouth is already an expert at making precise shapes without you noticing.  But outside of cleft palates and other conditions that affect mouth geometry, most people who struggle with whistling aren’t dealing with a hard “can’t.” It’s more a matter of degree, harder for some than others, but rarely impossible.  Age plays a real role, too. Maureen Stone, a speech scientist and professor emerita at the University of Maryland School of Dentistry, compares learning to whistle as an adult to picking up a new language later in life.  “If you take an adult and move them to a new country and tell them to learn a new language, they’re probably always going to have an accent,” she says. “But if you take a child and move them to a new country, it’s not a problem.”  The turning point, she says, is puberty. Whistling depends on precise muscle control in the lips and tongue, and once puberty hits, those same muscles become less adaptable. “It’s harder, in effect, to teach an old dog new tricks,” Stone says. Related 'Ask Us Anything' Stories Does summer actually make your hair grow faster? Holding in your sneezes really can hurt you Why 90% of us are right-handed Humans have weirdly white eyes. Here’s why. Yes, you can be allergic to water Why we have two nostrils instead of one big hole Why only humans sleepwalk How does whistling actually work? So, what’s actually going on inside your mouth when you whistle? Let’s whistle while we work through the mechanics.  Whistling only works if your lips and tongue form two very precise openings, which is part of why so many people struggle with it. Unlike talking or singing, it doesn’t rely on your vocal folds, more commonly called vocal cords, the vibrating structures in your throat that normally produce sound when you speak. During whistling, those vocal folds stay completely open and silent.  Instead, the open space between your throat and your lips, what scientists call the vocal tract, does the work: Your lips form a small opening in front, while the back of your tongue lifts toward the roof of your mouth, forming a second narrow gap further back. Air moving through these two points creates something close to a tiny, self-sustaining feedback loop. The tongue produces a small disturbance in the airflow, which travels forward to the lips. That disturbance bounces back as a pressure wave, traveling into the mouth again, where it interacts with the tongue once more. This happens hundreds of times per second, essentially volleying the sound back and forth until it locks into a clear, steady note. It’s the same basic physics as blowing across the top of a glass bottle, something we all did as kids without thinking much about it. The water in the bottle isn’t what makes the sound. It’s the empty air sitting above it. Less water means more room for that air to vibrate, which makes a lower sound. More water leaves less room, which makes a higher sound. Scientists call this a Helmholtz resonator, and whistling turns out your mouth is a surprisingly good one. But getting the shape right isn’t even the whole story. According to Prashanth Tamilselvam, a researcher who works with Ruiz at the Illinois Institute of Technology, you also have to blow with the right amount of force. Too soft, and nothing happens. Too hard, and it also fails. “There is a sweet spot when the whistling happens,” he says.  Training wheels for whistling  For people who fall into that “just haven’t figured it out yet” category, Ruiz has built something that might help. It’s called the Flutino. It’s a small, 3D-printed device shaped to guide the lips into the precise geometry whistling requires. The Flutino is smaller than a quarter, and shaped a bit like a small funnel.  Engineer Francisco Ruiz designed a device that helps people whistle. Video: Introducing the Flutino, Francisco Ruiz “This replaces your lips,” Ruiz says of his device. “Slip it between them [your lips], blow, and the device does the shaping work your mouth might not be doing correctly on its own.” Unlike other instruments, it works whether you’re blowing in or out, according to Ruiz.  Ruiz developed the idea during the pandemic, going through several prototypes before landing on the current design. In testing, the device has produced whistles up to 100 decibels, loud enough to be genuinely startling.  Ruiz’s Flutino is currently patent-pending and not yet available for purchase, but Ruiz has already begun exploring whether it could serve as a whistling teaching tool. A student group at UCLA, fittingly called the Whistling Club, is testing whether people who’ve never been able to whistle can learn to, using the device as training wheels of sorts. “They have not reported back to me yet,” Ruiz says. For Tamilselvam, who had difficulty producing a sustained whistle before joining the project, the breakthrough wasn’t a device: It was the hands-on knowledge he gained from participating in the research. Practice may not make perfect, but according to Tamilselvam, it makes a real difference.  “I would say I’m at least 50 or 60 percent better than what I was doing before,” he says. In Ask Us Anything, Popular Science answers your most outlandish, mind-burning questions, from the everyday things you’ve always wondered to the bizarre things you never thought to ask. Have something you’ve always wanted to know? Ask us. The post Can’t whistle? It’s not you, it’s mouth geometry. appeared first on Popular Science. ...read more read less