Health
Discover facts about health. Small discoveries that change the way you see familiar things.
Health
Anosmia is the complete inability to detect any odors
Normally, odor molecules switch on sensors in the nose, which send signals the brain recognizes as smells. With anosmia, those signals don’t reach or register…
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Exhaled breath contains trace amounts of argon gas
Argon is a gas in the air you breathe, and your lungs do not use it up the way they use oxygen. A little comes back out with each breath, so even an…
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Your language trains your tongue's movements
Different languages ask the mouth to make different sounds, and repeated practice trains the muscles that shape those movements. Over time, speakers get…
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Nasal cavities aggressively warm up freezing incoming air
Cold air passes over the warm lining of the nasal passages and gains heat on the way through. That warming helps shield delicate respiratory tissues from the…
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Why your voice sounds rough in the morning
When you lie flat, fluid can collect in tissues around your throat, including the area that shapes your voice. That mild swelling can make the sound rougher…
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Miracle fruit makes a lemon taste sweet without adding sugar
The fruit contains miraculin, a protein that changes how your sweet-taste receptors respond when your mouth is acidic. After you eat it, a lemon’s sourness…
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Why foods you hate can become favorites
Taste is not fixed for life: repeated experience can make a once-unfamiliar flavor seem more appealing. Olives may go from intensely bitter to something you…
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Human hearing can detect sounds as low as twenty hertz
At 20 hertz, the sound wave repeats only 20 times per second—the very low edge of human hearing. Because it is so low, you may notice it less as a clear…
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Singing requires engaging your diaphragm for proper force
When you sing, the diaphragm and other torso muscles help manage the air leaving your lungs. That steady breath support lets the vocal folds make sound…
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Umami has its own taste receptors
Umami isn’t a mash-up of salty, sweet, sour, or bitter. Glutamate in foods such as tomatoes and soy sauce activates taste receptors tuned to savory signals,…
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Speech turns your mouth into a rapidly changing instrument
Air from the lungs powers the voice, while the tongue, lips, and jaw continually reshape the sounds. Changing those positions converts the same airflow into…
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Chewing moves your lower jaw against a fixed upper one
The upper jaw forms part of the skull, while the lower jaw moves at joints in front of the ears. Muscles lift it and shift it from side to side to bring the…
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Holding your breath is overridden by autonomous urges
As you hold your breath, carbon dioxide builds up in your blood. The brainstem senses the change and increases the drive to breathe until automatic breathing…
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Why some people never get wisdom teeth
Wisdom teeth are third molars, and some people simply never develop one or more of them. If a tooth never forms, it can’t become impacted or crowd the teeth…
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Why losing 100 hairs a day can be perfectly normal
Scalp hairs aren’t all on the same schedule: some follicles are growing while others release a strand. That everyday turnover can add up to as many as 100…
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Your skin is your largest organ
Your skin also makes up about 15% of your body weight and constantly sheds dead cells. Its surface is a moving border: cells are replaced from below while…
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The fabric seller who revealed the microbial world
Grinding glass into tiny lenses gave Antonie van Leeuwenhoek a way to magnify what he was inspecting in cloth. The same sharp view revealed microorganisms too…
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Soap was once made from fat and ash
Wood ash can produce alkaline substances that react with animal fat to make a soap-like cleansing paste. The mixture could lift heavy grime, though it was a…
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Liquid soap had a U.S. patent in 1865
William Sheppard's patent described an improved liquid soap long before a pump bottle became a routine bathroom object. The cleaning substance and its…
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A sleep machine began by copying a motel air conditioner
According to Yogasleep's company history, Jim Buckwalter's wife slept better with the steady sound of motel air-conditioning. In 1962, he built a device to…
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Reusable menstrual cups were being marketed in the 1930s
The Smithsonian's collection includes early cups and advertising that promoted comfort, discretion and savings over disposable products. Leona Chalmers…
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When fire extinguishers were glass grenades
Before modern fire extinguishers became common, some households kept glass spheres filled with fire-suppressing liquid. In a fire, someone threw a sphere into…
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An 1880 eye-protector patent targeted furnaces, not a school lab
Powell Johnson designed protection for furnace workers, firefighters, and others exposed to intense glare. His patent describes layers and adjustable openings…
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Ancient sailors used beeswax as earplugs
Sound has to travel through the ear canal to make the eardrum vibrate, and beeswax can obstruct that route. The Odyssey’s sailors were using a simple physical…
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