52 things I learned in 2025

Previously: 2024, 2023, 2022, 2021, 2020, 2019

1 | About two-thirds of gendered animals in children’s stories are male. Frogs, wolves, and foxes are almost always male; birds, ducks and cats are the only common animals that are more often female.1 [The Pudding]

2 | Netflix commonly tells writers to “have this character announce what they’re doing” for people who have the show on in the background and aren’t really following. [Will Talvin via Derek Thompson]

3 | ChatGPT would need to answer at least 10 million questions to emit as much carbon as one cross-country flight. (If you’re concerned about water depletion instead: 200 responses use as much water as growing one almond.) [@AaronEstel, The Weird Turn Pro, more in this follow-up]

4 | Medieval Englanders stored coins in containers made from a clay called pygg. The vessels were called “pygg jars,” which became the “piggy banks” we know today. [Liberty Street Economics]

5 | Chicago pizza had been around for decades before it became known as “deep dish,” at which point it wasn’t that much different from other regional pizzas. But once it had the name, Chicago pizzerias leaned into it, making it “deeper and dishier” over time. [United States of Pizza]

6 | Fly balls travel a foot farther in Miami than in Seattle because gravity is stronger in the north. (Earth is not a perfect sphere; it bulges out a little at the equator.) [Effectively Wild]

7 | “Food comas” seem to be real: people who had eaten in the past hour scored 8% lower on a surprise test than people who hadn’t, with a larger effect on harder tests. (This held no matter when the test was given, so it’s not just a circadian-rhythm effect.) [Econstor via Gastropod]

8 | 17-year-old Birgit Felden won the 1984 Nathan’s Hot Dog Eating Contest for eating 9.5 dogs in 10 minutes. (For comparison, Joey Chestnut won this year’s with 70.5.) She was visiting New York on a nine-day trip from Germany with her judo club and had never eaten a hot dog before. [The Athletic via Shutdown Fullcast]

9 | Ikea serves food to 700 million customers per year; some say it’s the world’s sixth most popular chain restaurant.2 [Acquired podcast]

10 | Prediction markets for elections have shown a ‘momentum’ effect: if the price went up today, it’s more likely to go up over the next couple days, which also better predicts the final outcome. [No Dumb Ideas]

11 | Loud restaurants aren’t just annoying, they’re more dangerous, because shouting while eating spreads airborne diseases. [Complex Systems]

12 | More than 50% of Americans approve of using spanking to discipline children, even in the 18-29 and 30-44 age groups.3 [Family Stuff, see underlying GSS data here with some more details/crosstabs in this thread]

13 | The 1970 Vietnam draft lottery wasn’t random—people born in later months were disproportionately likely to come up earlier, because the balls weren’t mixed well before the drawing. [Misha Teplitskiy via Kent Hendricks]

14 | Rabbits rarely eat carrots; they prefer leafy greens. The association of rabbits with carrots was popularized by a 1940 Bugs Bunny cartoon. [@alexschmidtstagram]

15 | New York City’s hiring rules are absurdly bureaucratic: you have to choose an existing job description (or go through a long process to get a new one approved), find people who already took a test to make them eligible for that role without knowing which department might hire them, and then choose one of the three highest scorers on that test. (In practice, managers often look for weird titles that haven’t been tested so they can do their own interviews.) [Eating Policy]

16 | The “Taylor Rule”—a highly influential formula that observers often use as a guide for what interest rates should be (though the Federal Reserve doesn’t actually follow it)—comes from a paper that used only six years of data (1987-92).4 [Odd Lots]

17 | According to one study, attractive waitresses earn significantly more in tips, mainly because they get bigger tips from other women. [@MackenMurphy]

18 | Eric Adams was sworn in as NYC’s 110th mayor, but his successor Zohran Mamdani will be #112—a historian found that the city’s count missed Matthias Nicolls’ second (nonconsecutive) term in 1674, which the Department of Records has accepted. [Original finding reported by Gothamist, follow-up in archives.nyc with some more complications]

19 | In 1970, about 50% of US manufacturing was in the Rust Belt and 25% in the South; today those shares have flipped. [WaPo via Marginal Revolution]

20 | The reported total fertility rate has fallen in the US since 2000, but that’s just because women are having children later; 44-year-olds today have as many children as 44-year-olds in 2000. (That doesn’t mean everything is fine; even that corrected fertility rate is a little below replacement level, and the problem is worse/accelerating in many other countries.) [Mike Conczal]

21 | Mars (the company that makes M&Ms, Snickers, Skittles, etc.) owns more than 5% of US veterinarian practices and makes more revenue from pet care than from candy. [Acquired podcast]

22 | When one gram of ice melts, it releases 100 billion Terabytes of entropy. (Entropy in information theory represents how complex a message is—for example, adding extra characters to a password increases entropy—which is measured by how many bits it takes to encode the message, as in computer memory. Entropy in the physical world can also be framed the same way: you know exactly how molecules are arranged in solid form, but you don’t know where they are as liquid because they move around, so describing the matter requires more information.) [Simon DeDeo and relevant SMBC]

23 | According to the founder of Trader Joe’s, Thanksgiving is one of the best days to sell wine. Christmas is a bad day for wine but a good day for hard liquor. [Becoming Trader Joe]

24 | Mark Zuckerberg wanted to change his company’s name as early as 2018 (because Instagram and its other properties were growing while the “Facebook” app was declining), but he didn’t want to be seen as running away from bad PR at the time, so he was searching for a defensible reason. This probably explains the somewhat ridiculous change to ‘Meta’ a couple years later. [Facebook internal emails from FTC trial, they’ve since been taken down but the idea is mentioned here]

25 | Sidewalk chalk is no longer made of what chemists call chalk (calcium carbonate); it’s made of calcium sulfate instead. Blackboard chalk is usually chalk, but the chalk that gymnasts and LeBron use to improve their grip isn’t; that’s magnesium carbonate. [Wikipedia via xkcd]

26 | In 2005 Snapple tried to set a record with a 25-foot, 17-ton popsicle in NYC’s Union Square—but the frozen treat melted in the truck that was carrying it, spreading strawberry-kiwi goo across several streets. (”What was unsettling was that the fluid just kept coming,” a Guinness Book of World Records representative said.) [NBC News via ChatGPT]

27 | Lyndon Johnson and his wife owned a TV station in Austin while he was president and benefited—probably disproportionately—from advertiser payments. (He got a CBS affiliation after he was elected to Congress; it didn’t make business sense on the merits, but a senior network executive decided the political connection made it worthwhile. After Johnson became president, he frequently called CBS leadership to complain about their coverage.) [Charlie Brown’s Christmas Miracle]

28 | “Kermit”, “Grover” and “Elmo” were top-300 American boys’ names in the first half of the 20th century. (All fell out of the top 1000 by the 1970s or earlier; Sesame Street began in 1969.) [SSA via @whovian_delights]

29 | An often-cited stat claims that the median first-time homebuyer’s age has risen from 31 to 40 in the last decade. But that’s based on a single industry survey (with a low response rate) that’s probably wrong; government surveys and financial data show a younger median and little change in recent years. [Connor O’Brien, Lance Lambert]

30 | 2,000 calories of food (a standard daily recommendation) provide the same amount of energy used in driving a traditional car two miles, or an electric car 20 miles. [Energy Cheat Sheet]

31 | Intel became famous for powering Windows PCs in the 1980s. Apple probably would have used Intel chips in its first PC even earlier, but Steve Jobs lied to cofounder Steve Wozniak about how much they would get paid per computer (to keep a larger share for himself), so Wozniak chose a cheaper competitor to stay within budget. [The Intel Trinity]

32 | It’s generally illegal to use native American bird species in movies. Film animals are considered working pets, and early-20th-century avian protection laws banned domestication of native birds. [Slate]

33 | Placebo effects can affect social science studies, not just medicine: people who were told they were assigned to the control group of an experiment had worse outcomes than people who were in the same group but weren’t told about it. [Marginal Revolution]

34 | Although there are fewer living veterans today than in 2001, the number of disabilities compensated by the VA has grown from six million to 41 million. [@evanhill]

35 | Finland has more than one sauna for every two people. [NYT]

36 | Babies are gaining some gross motor skills like rolling and crawling later, because they’re developed on your tummy, and parents are now instructed to have babies sleep on their backs to prevent SIDS. [What to Expect the First Year]

37 | “Black raspberry” flavor comes from a plant that’s distinct from red raspberries or blackberries; it’s used in ice cream because red raspberries decay and lose their color when mixed with dairy. (”Blue raspberry” is an artificial flavor representing regular raspberries; food companies used blue dye for it because cherry and strawberry were already red.) [several sources, see this ChatGPT thread]

38 | Post-tax incomes rose at about the same rate for all economic classes in the US over the last 50 years. (The top 1-5% had higher pre-tax growth, but policy has become more redistributive.) [SSRN]

39 | “Big spoon” and “little spoon” are nonsensical terms for cuddling, because spoons only fit next to each other neatly if they’re the same size. [xkcd]

40 | The number of Americans in prison has declined by 25% since 2009 and is expected to fall another 50% over the next decade. This is because crime rates have gone down since the 90s, but many people convicted in that era are still incarcerated on sentences that will end soon. [The Atlantic]

41 | Denver International Airport is larger than the entire city of San Francisco or Boston. [@mehran__jalali]

42 | According to one estimate, a single pitch being a ball or strike is worth about $80k to a baseball team on average.5 [Effectively Wild]

43 | When the USPS first accepted large packages, at least eight families mailed their children to a relative or neighbor (including one all the way from Florida to Virginia). [History TV]

44 | Private equity firms often seek out small local companies that don’t have a website, make a website so more customers can find them, and benefit from the easy growth. So some business owners are now taking down their websites to fool lazy PE buyers into buying them. [Don’t Worry About the Vase]

45 | Sans-serif fonts have taken over because they render better on small phone screens. [Sharp Tech]

46 | Chromosomes only form the classic “X” shape when they’re dividing; they’re usually more tangled. [How Life Works]

47 | How do camera crews keep their pictures clear in rain or snow? They put a fast-spinning disk above the lens, which isn’t noticeable but shakes off precipitation. [vt.physics]

48 | When home improvement companies (or other big-ticket purchase sellers) offer something like “12 months to pay back without penalty and then a high rate”, it’s not really a trick to try to get you to pay more—they’re just trying to get you to lock in a sale as soon as possible, even if you need time to complete your own financing later. [Patrick McKenzie]

49 | In 2018 a golfer played the entire country of Mongolia as one hole, taking 20,093 shots to cover 2.2 million yards. His caddy carried 400 balls for the 80-day trip. (A random dog joined them on day two and stayed with them the entire rest of the way.) [The Longest Hole via Shutdown Fullcast]

50 | Public opinion swings against the views of the president’s party even during successful terms. (For example, Americans became much more liberal throughout the Reagan era.) [James Stimson via @SpecialPuppy1]

51 | “Hot chocolate” and “hot cocoa” are technically different drinks—the former is made with real chocolate while the latter is made with cocoa powder (which is sweeter but less rich since it doesn’t have most of the fats). [@halfbatchbaking]

52 | The length of written and spoken sentences has been falling for centuries. There isn’t an obvious explanation, but one theory is that shorter sentences are clearer and people have just become better at communicating. [Arjun Panickssery]