Maybe it’s ice clinking in a mug. Maybe it’s obscenely crunchy chewing. Maybe it’s a dreaded case of loud breathing. Whatever the tick, it’s undeniable: sounds can be maddening. But how is it that something so intangible can wield so much power over the human psyche? After all, it’s not like you can see the megahertz and decibels.
Well, a look at the science reveals that, out of all the senses, sound might very well be the most complex. Sound can annoy you, but it can also calm you, energize you, or even send your mood to stratospheric highs. Sound can create natural phenomena hitherto unexplained. Oh, and get this: sound actually can be seen.
That’s right: Get ready to have your mind (though, thankfully, not your ears) blown, because here, we’ve cobbled together the most fascinating things science has to say about this essential and commonly misunderstood sense.
This Is Why Loud Breathers Annoy You
If there’s a specific sound that drives you nuts—whether loud breathing or otherwise—you might be suffering from misophonia, or a sensitivity to certain sounds. Diagnosed misophonics pointed to “mouth noises” as the most common annoyance—chewing, lip smacking, and especially loud breathing all qualify.
The intense dislike of the sound of breathing triggers something in the anterior insular cortex of the brain (or at least the brains of those who are sensitive to the sounds). That’s the part of the brain that plays a role in emotions like anger and in “integrating outside inputs (such as sounds) with inputs from organs such as the heart and lungs,” as James Cartreine explains in the Harvard Medial School blog—and it doesn’t respond the same way to sounds that aren’t produced by the human body. In studies of those who are especially sensitive to mouth breathing, more neutral sounds—from the soothing sound of rainfall to the not-so-dulcet tones of babies crying—didn’t lead to as much agitation as the noise of loud breaths.
The good news is that a therapy exists to treat misophonia. The bad news is that it’s a type of desensitization therapy, which means, if you’re interested in trying it, you’ll have to listen to the sound over and over again until your negative emotions decrease.
Sonic Booms Happen When an Object Catches Up to Its Own Sound
What exactly is a sonic boom? Well, since sound is a wave, picture for a moment a pebble dropped into a lake—the ripples that spread out in every direction are comparable to the sound waves that travel away from an object making noise. Now imagine a pebble hitting the water and then zooming across the surface. If the pebble went fast enough, it would soon overtake the farthest wave that it initially caused by hitting the water. When an object travels faster than the first sound wave it produced, it breaks the sound barrier and creates a sonic boom.
Sound Can’t Travel through Outer Space
In space, as the iconic line goes, no one can hear you scream. But do you know why? It has nothing to do with aliens or Sigourney Weaver. A sound is a series of pressure waves that travel through matter. Usually, we think of sound waves as traveling through the air directly into our ears, but they can travel through liquids and solids, too. If there’s no matter, however, the sound wave has nothing to travel through; like an ocean wave hitting the beach, it can go no further. Space is a vacuum, which by definition contains no matter, so anything you might yell out there goes no farther than the walls of an air-containing spaceship.
You Really Can Feel the Rhythm
Moving to the other end of the spectrum, low-pitched sound waves move more slowly than their high-frequency counterparts. As a result, if you turn up the volume on low sounds, you can actually feel them move through your body. Have you been to a concert and felt the thud of the bass? Have you felt a loud thunderclap in your body the same time you hear it with your ears? That’s the feeling of sound waves moving through you.
The Loudest Sound on Earth Came from a Volcano
The loudest sound in recorded history that humans could hear was the eruption of Mt. Krakatoa in 1883. When this Indonesian volcano erupted, in four separate explosions, the sounds could be heard more than 3,000 miles away. To put that in perspective, if that sound had come from New York City, you’d be able to hear it in both Los Angeles and Dublin, Ireland. Anyone within 40 miles of the volcano itself suffered ruptured eardrums.
Sound Can Take a “Picture” of an Unborn Baby
You probably know that the machine doctors use to take a look at a baby still inside the womb is called an ultrasound, but you might not know that the machine makes an image out of sound waves. A technician uses a special wand to direct very high-frequency (and completely harmless) sound waves through the mom’s abdomen, and the sounds bounce back at different frequencies for different types of tissue: bones, cartilage, fluid. The ultrasound machine then interprets this sound map in different colors or different shades of gray, allowing the doctor and the expectant parents to “see” the shape of the baby.
Animals Can “See” With Sound
Just like an ultrasound machine can turn different frequencies into a picture, so can some animals use sound to maneuver through the world. This ability is called echolocation, and though bats are easily the most famous for it, some birds, whales, and dolphins also echolocate. These animals produce a sound and listen as it bounces off different objects; their brains then interpret the different echoes into distances. Humans can do the same with SONAR machinery, but some—particularly visually-impaired people—can learn to do it themselves through training and practice.
Airplanes Can Travel Faster Than Sound
Sound travels slower than light, but it still travels pretty fast—758 miles an hour at sea level, in fact. When anything travels faster than that, we call it “breaking the sound barrier,” and it creates a loud noise known as a sonic boom (see previous slide). The first human to break the sound barrier was WWII fighter pilot Chuck Yeager, who flew a secret military plane faster than the speed of sound on October 14, 1947. He named his plane the “Glamorous Glennis” after his wife.
Whips Break the Sound Barrier, Too
Airplanes aren’t the only thing that can go faster than sound. If you’ve ever seen a lion tamer or a cowboy crack a bullwhip, you might assume that the sound of the crack comes from the whip hitting something hard. In fact, the crack is a tiny sonic boom, which occurs when the person wielding the whip flicks a loop that travels faster and faster down the whip until it breaks the sound barrier. That means the skinny end of the whip is going faster than 758 mph!
Dogs Can Hear Things That Humans Can’t
There’s a huge range of sound out there, but human beings can only perceive some of it. Sound pitch is measured in hertz—the lower the pitch, the lower the number—and humans can only hear sounds between about 20 Hz and 23 kHz (kilohertz). However, because of their sensitive ears, dogs can hear sounds up to 45 kHz. That’s why a human can’t hear a dog whistle, but a dog can. Dog whistles can be great training tools, but they must be used carefully. After all, how likely would you be to listen to your boss if they blasted a horn in your face whenever you screwed up?
Sound Helps Plants Grow
You may have heard that playing a certain type of music for your plants will make them grow faster, and some studies have shown this to be true. However, they also discovered that it was six hours of sound a day, not necessarily music, that made the difference. It’s not known exactly why this effect occurs, but it’s possible that plants have special mechanoreceptors that let them receive sounds. Whether you like classical or jazz, rock or polka, or even just talk radio, let your houseplants listen in, too.
Music Affects Your Mood
Though plants don’t discriminate between music and non-musical sounds, the human brain clearly does. Music can have a variety of effects on the brain, creating emotions that release dopamine, helping reconnect us with our memories, creating new neural connections to help us learn, and improving our attention span. Some people believe that engaging with music by playing an instrument, singing, chanting, or drumming can increase feelings of wellness and balance while decreasing stress and anxiety.
Doctors Can Use Sound to Destroy Kidney Stones
If focused in the right way, sound can be extremely destructive; pressure waves can wreak havoc on the matter through which they pass. Medical science has harnessed this power in a procedure called extracorporeal shock wave lithotripsy—a method of breaking up kidney stones. In this procedure, the doctor finds the precise location of the stone and then uses a special instrument that directs high-frequency sound waves through your body. Though the waves don’t hurt your muscles or organs, they pulverize kidney stones into much smaller pieces, making them easier to pass.
Noise-Cancelling Technology Fights Sound with Sound
Noise-cancelling headphones can be a godsend in a loud or crowded environment. You might think they just do a really good job of muffling noise, preventing sound waves from reaching your ears. However, what they actually do is take in the ambient sounds around you and add a second, inverted sound wave to cancel them out. The combined effect of these two waves in your ears is blissful silence.
Some People Can See Color
The term synesthesia refers to a condition where the stimulation of one sense leads to the stimulation of another. Any of the five senses can be involved, but chromesthesia refers specifically to people who perceive sounds as colors. Which sound produces an experience of which color is unique to the person, but they stay consistent over time—someone who perceives middle C as purple will always perceive middle C as purple. Some of these chromesthetes even report associating colors with certain voice pitches and accents.
Like Optical Illusions, Auditory Ones Exist, Too
In May of 2018, anyone with an internet connection was asked the question “Do you hear ‘Yanny’ or ‘Laurel’?” That viral audio clip—in which both sounds could be heard—is an example of an auditory illusion, the ears’ equivalent of an optical illusion. Believe it or not, accomplished psychologists and audiologists weighed in on the phenomenon, calling it a “perceptually ambiguous stimulus” akin to the visual face/vase illusion. A similar effect can be created with the words “brainstorm” and “green needle.”
Music Improves Athletic Performance
In 2007, the New York Marathon forbade its athletes from listening to music as they ran, and the runners immediately protested. As it turns out, music has a measurable effect on these athletes’ bodies. Music can draw attention away from fatigue, regulate physiological arousal as well as movement, assist in gaining new motor skills, and promote a state of “flow,” an ideal combination of energy and focus. Ultimately, the marathon’s organizers realized that they couldn’t enforce the music ban, so no runners were disqualified for listening to their tunes.
Your Favorite Song Changes Rapidly… And Not at All
Do you have a lifelong favorite song, a song that’s stuck with you over the years and stands out as particularly meaningful to you? How many a times a day do you listen to it? If you’re like most people, probably not many. It seems that most people have two types of “favorite songs“—those that they listen to day-to-day and those that they’ve loved for years. The former change rapidly, but the latter stay constant because they’re associated with intensely emotional memories.
The Bloop Has Been Solved
In 1997, hydrophones (underwater microphones) across the Pacific picked up a long, extremely low sound with no apparent origin. Unsure what to call it, oceanographers got together and decided on… “the Bloop.” Even if you’ve never heard it, you can guess what it sounds like. For years, this sound was a great unsolved mystery, with many people imagining that only a huge sea monster could produce such a noise. Sadly, the real answer isn’t quite so dramatic—in 2012, scientists announced that the Bloop was consistent with the sounds glaciers make when they break or carve through the sea bed.
No One Knows Why Earthquakes Happen in the Sky
Speaking of unexplained sounds, there’s a sonic phenomenon that’s been reported all over the world, from India to Japan to Italy to the United States, that sounds like a cannon shot from the sky. Sometimes called “skyquakes,” these sonic boom-like noises typically occur near large bodies of water and can cause shockwaves that rattle windows. They’ve been known to occur around Seneca Lake in New York, earning the nickname “Seneca guns.” People have hypothesized numerous causes, from solar flares to underwater caves to UFOs, but none of these explanations are entirely satisfactory.
Lyrebirds Are the World’s Greatest Sound Mimics
The Australian lyrebird puts the mockingbird to shame in the impressions department. In addition to its magnificent tail feathers, the lyrebird has such complex musculature in its throat that it can not only mimic other birds, but koalas and dingoes as well. It can even mimic human sounds such as chainsaws, car alarms, cell phone rings, crying babies, and video game noises. There are some reports of a population of lyrebirds that took to mimicking the song a local man played on his flute in the 1930s, passing the song down generation by generation so that it can still be heard today.
Your Brain Loves Those Stuck-in-Your-Head Tunes
Some people call it “repetunitis.” Scientists call it “melodymania.” You might call it an “earworm”—that song that always seems to get stuck in your head. Theories vary as to why this happens. Some say it’s the brain trying to amuse itself while it’s idling. Other say it’s like trying to suppress a thought—the harder you try to ignore it, the louder it seems to get. However, certain features of a song make it more likely to be an earworm: a simple melody, catchy lyrics, and an unusual feature like an extra beat. (Incidentally, this describes nearly every commercial jingle you’ve ever heard.)
Some People Can Hear Their Eyes Move
The bones in your inner ear allow you to hear sound by picking up the vibrations of the sound waves and translating them into information your brain can interpret. For some people, however, the vibrations don’t just come from outside sound. We can all hear the noises our own bodies make: speaking, chewing, and cracking joints, for example. However, people with superior canal dehiscence hear their bodies too well—because of the thinning of a protective bone in the skull, they can constantly hear their own heartbeat, digestive sounds, and even eye movements while reading!
Sound Can Kill You
You probably know that sound volume is measured in decibels. Regular speech clocks in at around 50 decibels, vacuum cleaners and highway traffic are about 70 decibels, and heavy construction machinery—which can damage your hearing—is around 100 decibels. Sounds above 110 decibels will cause immediate pain, and sounds at or above 150 decibels will rupture your eardrums. At around 185 to 200 decibels, a sound would actually be loud enough to kill you. However, sounds that loud only occur at the site of huge explosive blasts—at which point you’ve got bigger problems than sound.
The “Big Bang” Was More Like a Hum
During the Big Bang, all the matter in the universe expanded from a single, infinitely dense point out to hundreds of thousands of light years. With an explosion like that, you’d certainly expect a bang. However, when physicist John Cramer measured background radiation in the very farthest edges of the universe and converted it to sound, what he got was “somewhere between a video game character dying [and] an old-school computer powering down.” It was also so low that even if you’d been there, you wouldn’t have been able to hear it. What it lacked in volume, though, it made up in length: the Big Bang potentially continued for as long as 700,000 years.
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