How does general anesthesia work? This question came from a reader submission (thanks Ana!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question π The short answer General anesthesia works by disrupting how brain cells communicate, leading to unconsciousness, immobility, and pain relief. While the exact mechanism is still unclear, anesthetics appear to either flood neurons with charged molecules or block them entirely, breaking down...
14 days agoΒ β’Β 6 min read
Longtime readers of Today You Should Know may recognize this question β it's a repeat! It's been a busy season of life lately. So I thought I'd resend this previous newsletter, which I bet is the only email in your inbox that touches on both birds and quantum physics. All my best, π Caitlin How do birds navigate during migration? This question came from a reader submission (thanks Tej!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your...
21 days agoΒ β’Β 5 min read
Who decides which emojis get made? π The short answer The Unicode Consortium's Emoji Subcommittee accepts new emoji proposals from the public every year and evaluates them based on strict criteria, including how useful, recognizable, and broadly relevant the emoji would be. π The long answer I'm going to take a wild guess that you've used an emoji today. But actually, the guess isn't that wild π β 92% of the worldβs online population uses emojis*. Currently there are 3,953 emojis when all...
28 days agoΒ β’Β 6 min read
Why does nails on a chalkboard give you chills? This question came from a reader submission (thanks Casey!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question π The short answer Nails on a chalkboard sound awful because our ears naturally amplify those frequencies. It's theorized that we evolved this sensitivity to better detect the warning calls of our primate ancestors. π The long answer Hearing nails scraped on a chalkboard is a...
about 1 month agoΒ β’Β 3 min read
How do cruise ships turn around? This question came from a reader submission (thanks Mom!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question π The short answer Cruise ships turn around in tight spaces using a combination of bow thrusters, which move the front of the ship sideways, and azimuth thrusters, which rotate 360Β° to steer and propel the ship. These systems allow precise movements without relying heavily on tugboats. π The long...
about 1 month agoΒ β’Β 4 min read
Why does drinking something cold make you cough? This question came from a reader submission (thanks Lionel!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question π The short answer Cold drinks may trigger coughing by rapidly cooling the esophagus and, by proximity, the trachea, which can cause the airways to tighten and lead to coughing. π The long answer While I've personally only experienced brain freezes when drinking a cold...
about 2 months agoΒ β’Β 3 min read
How is plastic being removed from the ocean? 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 π The short answer Plastic is being removed from the ocean with boat-towed nets, but more effort goes into stopping it upstream by trapping it in rivers and cleaning beaches. Scientists are also testing ways to remove microplastics using filters, magnets, and microbes that clump or...
about 2 months agoΒ β’Β 8 min read
Why do we zone out? This question came from a reader submission (thanks Aastha!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question π The short answer When we zone out, brain regions that process external stimuli decouple from our introspective default mode network, causing our mind to wander without us realizing. Zoning out gives the brain a chance to rest, reflect, and solve problems. π The long answer As you begin reading this...
2 months agoΒ β’Β 6 min read
Why do cartoon characters have four fingers? π The short answer Cartoon characters typically have four fingers to simplify animation and keep characters from looking too human, while Japanese anime characters have five to avoid negative cultural associations. I'm in end-of-the-year-reflection-mode and am working on a "Best of 2025" list to jot down life learnings, favorite books, tools I want to bring with me into the new year, etc. If you're interested in this more personal email from me,...
2 months agoΒ β’Β 6 min read