Do sports teams that train in high altitudes have a home advantage? This question came from a reader submission (thanks Jacqui!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question ๐ The short answer There is strong statistical evidence that high-altitude teams have a home advantage, largely because visiting players experience reduced oxygen intake and quicker fatigue at elevation. ๐ The long answer It's high time we level up our...
17 days agoย โขย 7 min read
How was bread invented? This question came from a reader submission (thanks Rodrigo!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question ๐ The short answer Bread originated over 14,000 years ago with early humans baking ground wild grains on hot stones. Over time, developments in agriculture, fermentation, and oven construction led to increasingly specialized and widespread bread production across ancient civilizations. This week's...
24 days agoย โขย 7 min read
Why does your stomach growl? This question came from a reader submission (thanks Cory!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question ๐ The short answer Stomach growling is caused by muscle contractions that move food, liquid, and gas through your digestive system. These sounds are amplified when your stomach is empty but also occur during digestion after a meal. This week's newsletter is sponsored by 1440, a free daily U.S. news...
about 1 month agoย โขย 5 min read
Longtime readers of Today You Should Know may recognize this question โ it's a repeat! My dad and I are currently on a much-anticipated, multi-day bike trip. Unfortunately I didn't manage to crank out a new newsletter before cranking on my pedals, so I hope you enjoy (re)learning the physics of biking. I sure am enjoying them right now. All my best, ๐ ๐ดโ๏ธ Caitlin Why is it easier to balance on a moving bike? This question came from a reader submission (thanks Dad!). Has a curious question...
about 1 month agoย โขย 5 min read
Where does trash go? This question came from a reader submission (thanks Zuzu!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question ๐ The short answer Trash typically goes through a multi-phase journey: it's first collected and sorted, then processed at various facilities depending on its type. Most waste ends up in landfills, but some is recycled, composted, incinerated for energy, or even exported. Last week, I asked how you'd feel if...
about 1 month agoย โขย 9 min read
How does Today You Should Know work? This question came from no one in particular, but seeing as this is the 150th edition of the newsletter, I thought I'd do a behind-the-scenes. I could not come up with all these newsletter topics on my own, so please keep the curious questions coming! Submit your question ๐ The short answer Fueled by reader-submitted questions, I work on Today You Should Know nearly every morning โ researching, creating custom diagrams, writing, editing, and managing the...
about 2 months agoย โขย 9 min read
How do controlled burns work? 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 ๐ The short answer Controlled burns, or prescribed fires, are intentionally set by professionals to reduce wildfire risk and support ecosystem health. Burn bosses must get a rigorous burn plan approved and execute with carefully designed ignition methods and timing to control fire behavior. ๐ The...
about 2 months agoย โขย 6 min read
Why do we have leap years? This question came from a reader submission (thanks Shi So!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question ๐ The short answer Leap years exist because a full orbit around the Sun takes 365.242189 days, so we add extra days to keep our calendar aligned with the seasons. The Gregorian calendar uses specific leap year rules to stay closely synced with the solar year, skipping three leap years every 400...
2 months agoย โขย 5 min read
What causes dark circles under your eyes? 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 ๐ The short answer Dark circles under the eyes can result from true hyperpigmentationโcaused by excess melanin, iron deposits, skin thickening, or visible blood vesselsโor from shadowing effects due to changes in under-eye volume like hollowness or puffiness. ๐ The long answer Perhaps...
2 months agoย โขย 7 min read