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πŸ’‘ Today You Should Know

Learn something new every Friday. Join 2,000+ nerds and satisfy your curiosity one question at a time with topics including science, technology, history, and more.

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Why do we feel colder as we age?

Why do we feel colder as we age? This question came from a reader submission (thanks Gary!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question πŸ““ The short answer Aging causes your body to produce less heat, lose it more easily through thinner skin, and be slower to trigger warming responses, so we feel colder than we did when we were younger. πŸ“š The long answer Aging β€” if we're lucky β€” comes for us all. One day you're a reckless...

A badminton racket and a ball on a table

Why does a shuttlecock turn when you hit it? This question came from a reader submission (thanks anonymous!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question πŸ““ The short answer A shuttlecock turns when you hit it because most of the mass sits near the compact cork, while the wide skirt catches most of the aerodynamic resistance. That offset creates a torque that flips it cork-forward within about 20 milliseconds of impact. πŸ“š The long...

total lunar eclipse

Are humans affected by the Moon? This question came from a reader submission (thanks Soju!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question πŸ““ The short answer While science hasn't found convincing evidence linking the lunar cycle to mental health or menstruation, there is evidence that moonlight disrupts sleep around a full moon, possibly through an innate circalunar rhythm. πŸ“š The long answer The Moon: Earth's little sidekick, the...

person holding balloons

Longtime readers of Today You Should Know may recognize this question – it's a repeat! Life has been very full lately (in good ways, fortunately!), and I'm trying to be better at taking rest when I need it. So please enjoy this re-run of a newsletter all about Κ°αΆ¦α΅Κ°β»α΅–αΆ¦α΅—αΆœΚ°α΅‰α΅ˆ voices. All my best, πŸ‘‹ Caitlin Why does helium make your voice higher? πŸ““ The short answer When you inhale helium, the gas's lower density speeds up sound waves, amplifying higher frequencies in your voice while dampening...

couple wearing silver-colored rings

Why is the "ring finger" the ring finger? This question came from a reader submission (thanks Rayvan!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question πŸ““ The short answer We typically wear rings on the β€œring finger” because the ancient Egyptians believed a special vein ran from the fourth finger on the left hand straight to the heart. The Romans later gave this idea a romantic name: the β€œvein of love.” πŸ“š The long answer Humans (and...

black android smartphone displaying qr code

How do QR codes work? This question came from a reader submission (thanks Nathan!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question πŸ““ The short answer A QR code is a binary message your camera can read. The grid of black and white squares encodes data, while built-in structural markers tell the scanner how to orient the code, how it's formatted, and how to reconstruct any missing pieces. πŸ“š The long answer Back in the 1990s, Masahiro...

Contact lens.

How do contact lenses work? This question came from a reader submission (thanks anonymous!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question πŸ““ The short answer Contact lenses correct refractive errors, like nearsightedness, farsightedness, and astigmatism, by using precisely shaped lenses to bend incoming light so it lands on the retina instead of in front of or behind it. πŸ“š The long answer As someone with a mild aversion to putting...

a bird on a tree

Why do nuthatch birds walk upside down? This question came from a reader submission (thanks Nancy!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question πŸ““ The short answer Nuthatches climb down trees headfirst to forage more efficiently. By approaching the bark from above, they can spot hidden food that upward-climbing birds may miss. πŸ“š The long answer Say hello to the nuthatch. πŸ™ƒπŸ‘‹ "Sitta-carolinensis-001" by Mdf is licensed under CC...

brown brain decor in selective-focus photography

Can the brain heal itself after a stroke? This question came from a reader submission (thanks Aunt Genie!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question πŸ““ The short answer After a stroke, the brain can reorganize its neural pathways to recover lost functions through neuroplasticity. The best way to promote healing is consistent practice of the affected functions, like deliberately using the weaker side of the body for everyday...

coconut water

Why do coconuts have water? This question came from a reader submission (thanks Akaal!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question πŸ““ The short answer Coconuts carry water because they’re designed to launch a seed with an immediately usable food reserve. This liquid endosperm supports early growth, while the meat provides sustained fuel as the seedling develops. πŸ“š The long answer Coconuts are an unusual fruit (yes, they are a...