Why does stress cause people to overeat? This question came from a reader submission (thanks M Meg!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question π The short answer Stress fuels overeating because it triggers the release of cortisol, a hormone that ramps up appetite and urges your body to stockpile energy for future threats, particularly with calorie-dense food. π The long answer Overeating is a very common response to feeling...
11 days agoΒ β’Β 6 min read
Why do cranes have flags on them? This question came from a reader submission (thanks Natalie!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question π The short answer Cranes fly flags to indicate wind conditions, display patriotism or remembrance, and comply with airport safety rules. π The long answer Whether you're considered an umarell or not, you may have noticed before that flags are often flown on construction cranes. Wikipedia...
18 days agoΒ β’Β 5 min read
Why do we say "achoo" when we sneeze? This question came from a reader submission (thanks Duncan!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question π The short answer "Achoo" mimics the sound of the sneeze itself, shaped by how we breathe and move our mouth. But not everyone says "achoo" since different languages have their own versions, and making a sound at all is a cultural habit, not a biological need. π The long answer We've all...
25 days agoΒ β’Β 3 min read
What happens to the temperature of the atmosphere the higher you go? This question came from a reader submission (thanks Omar!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question π The short answer The higher you go in the atmosphere, the temperature either rises or falls depending on the layer. These changes are caused by how different parts of the atmosphere absorb energy from the Sun and how air pressure affects heat. π The long...
about 1 month agoΒ β’Β 7 min read
Why do men have nipples if they can't breastfeed? This question came from a reader submission (thanks Pedro's daughter!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question π The short answer Men have nipples because all embryos start developing the same way, and nipples form before sex-specific genes activate. They likely remain simply because thereβs no evolutionary pressure to remove a harmless trait. π The long answer Great thinkers...
about 2 months agoΒ β’Β 4 min read
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 π 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. π The long answer It's high time we level up our...
about 2 months agoΒ β’Β 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 π 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...
about 2 months agoΒ β’Β 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 π 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...
2 months agoΒ β’Β 5 min read
Longtime readers of Today You Should Know may recognize this question β 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, π π΄βοΈ Caitlin Why is it easier to balance on a moving bike? This question came from a reader submission (thanks Dad!). Has a curious question...
2 months agoΒ β’Β 5 min read