Learn about the evolutionary reason why older people wake up early; new research that could explain why hot water can freeze faster than cold water; and the truth behind the recapitulation theory that embryos repeat evolution. In this podcast, Cody Gough and Ashley Hamer discuss the following stories from Curiosity.com to help you get smarter and learn something new in just a few minutes: There's An Evolutionary Reason Older People Get Up Early — https://curiosity.im/2HZ08h2 Hot Water Can Freeze Faster Than Cold Water, And Nobody Knows Why — https://curiosity.im/2HWEry1 Recapitulation Is the Debunked Theory That Embryos Repeat Evolution — https://curiosity.im/2HUkW9k If you love our show and you're interested in hearing full-length interviews, then please consider supporting us on Patreon. You'll get exclusive episodes and access to our archives as soon as you become a Patron! https://www.patreon.com/curiositydotcom Download the FREE 5-star Curiosity app for Android and iOS at https://curiosity.im/podcast-app. And Amazon smart speaker users: you can listen to our podcast as part of your Amazon Alexa Flash Briefing — just click “enable” here: https://curiosity.im/podcast-flash-briefing.
Learn about the evolutionary reason why older people wake up early; new research that could explain why hot water can freeze faster than cold water; and the truth behind the recapitulation theory that embryos repeat evolution.
In this podcast, Cody Gough and Ashley Hamer discuss the following stories from Curiosity.com to help you get smarter and learn something new in just a few minutes:
If you love our show and you're interested in hearing full-length interviews, then please consider supporting us on Patreon. You'll get exclusive episodes and access to our archives as soon as you become a Patron! https://www.patreon.com/curiositydotcom
Download the FREE 5-star Curiosity app for Android and iOS at https://curiosity.im/podcast-app. And Amazon smart speaker users: you can listen to our podcast as part of your Amazon Alexa Flash Briefing — just click “enable” here: https://curiosity.im/podcast-flash-briefing.
Find episode transcript here: https://curiosity-daily-4e53644e.simplecast.com/episodes/why-older-people-get-up-early-why-hot-water-freezes-quickly-and-recapitulation-myths
CODY: Hi! We’re here from curiosity-dot-com to help you get smarter in just a few minutes. I’m Cody Gough.
ASHLEY: And I’m Ashley Hamer. Today, you’ll learn about the evolutionary reason why older people wake up early; new research that could explain why hot water can freeze faster than cold water; and the truth behind a theory that embryos repeat evolution.
CODY: Let’s satisfy some curiosity.
There's An Evolutionary Reason Older People Get Up Early — https://curiosity.im/2HZ08h2 (Ashley)
ASHLEY: Research suggests there’s an evolutionary reason why older people wake up early. And the science says this bedtime quirk might be a feature, not a bug. For a study published in Proceedings of the Royal Society B, researchers recruited volunteers from a hunter-gatherer society in northern Tanzania, called the Hadza [HAD-zuh]. They live in groups of 20 to 30 people, and they spend their days finding berries, tubers, and meat in the savanna woodlands. They typically sleep outside next to a fire or inside woven-grass huts. Importantly, they sleep on the ground without artificial lighting or climate control, so their environment is pretty similar to that of early humans. Scientists look at modern hunter-gatherer societies like this all the time, when they’re doing research on how early humans may have lived. The Hadza live in the modern world, but some elements of their lifestyle have stayed the same for centures — as in, elements that are similar to how researchers think our human ancestors used to live, before agriculture came long. So for this study, the researchers had 33 men and women between the ages of 20 and 60 wear a sleep-tracking watch for 20 days. They found that very few of the Hadza slept at the same time. Some people, especially older participants in their 50s and 60s, went to bed as early as 8 p.m. and woke up at 6 a.m. 20- and 30-somethings, on the other hand, often stayed up until past 11 and slept in until after 8. Most participants got up a few times in the middle of the night to tend to babies or relieve themselves. But here’s the shocker: out of more than 220 hours of observation, there were only 18 minutes in the entire study where all 33 participants were asleep at the same time. On average, more than a third of the group was awake (or at least only lightly resting) at any given time. Researchers think that this sleeping mismatch helped our ancestors survive. Predators can attack at any hour, and if a few people are always awake, someone is always around to guard against danger. Plus, you don't need to assign people to keep watch overnight if someone's already going to be up. Bottom line? If you're getting older and you’re having trouble sleeping past 7 a.m., there may not be anything wrong. It's probably just millennia of evolution helping you watch out for lions.
Hot Water Can Freeze Faster Than Cold Water, And Nobody Knows Why — https://curiosity.im/2HWEry1 (from Saturday) (Cody)
Under certain conditions, hot water freezes faster than cold water. Have you ever wondered what’s up with that? Well, so have scientists. A new hypothesis may have finally figured out why this happens. The phenomenon I’m talking about is called the Mpemba [Muh-PEM-bah] effect, named after a Tanzanian student named Erasto B. Mpemba. Yep, it’s another story with ties to Tanzania. What are the odds? Anyway, in the late 1960s, Mpemba ran some experiments and found that under certain conditions, hot water freezes faster than cold water. But scientists still don’t exactly agree on those conditions, and the fact that the effect doesn't happen every time makes it kinda hard to study. Probably part of the reason why scientists don’t all agree on WHY it happens, either. For a long time, the most popular idea was that hot water evaporates more quickly, so it loses more mass and needs to lose less heat to freeze. The Mpemba effect happens in closed containers with no evaporation, though. A different explanation showed up in 2013, when there were reports that a team of researchers from Singapore had found the answer. They said the bonds between molecules in boiling water are more flexible and ready to give up energy (in the form of heat) than those in cool water. Scientists didn’t love this explanation, either, because it still didn’t explain why the effect only happens sometimes. Well in January, researchers came up with a new hypothesis, and it relies on the idea that the bonds between H2O molecules structurally change in response to temperature. Basically, the molecules in hot water are constantly movin, so there’s a lot of disorder in the system — a.k.a. entropy. Cold water molecules usually cluster together and make weak bonds. As the water heats up, these bonds break. So in the same way you’ll get colder on your own than when you're huddled with a group of friends, these buzzing hot-water molecules may be able to form ice crystals in a freezer faster than the clusters of cold-water molecules, since they have a tighter arrangement that takes time for the temperature to change. Importantly, this effect wouldn't necessarily appear if there were a lot of salts and minerals dissolved in the water, since that water wouldn't form as many clusters at cold temperatures.This explanation neatly addresses both the phenomenon itself and the difficulty of repeating it under laboratory conditions — but that doesn't necessarily mean it's true, either. File this under “maybe, but we’ll get back to you when we know for sure.”
[NHTSA]
ASHLEY: One thing we DO know for sure is that today’s episode is paid for by the National Highway Traffic Safety Administration. NIT-suh is working hard to combat texting while driving.
CODY: Texting and driving isn’t just a dangerous problem, it’s deadly. And if you drive
while distracted, you’re THREE TIMES more likely to crash. But far too many people still don’t recognize the dangers. Did you know that when you send or receive a text, you take your eyes off the road for about 5 seconds? And at 55 miles per hour, that’s like driving more than the
length of a football field, with your eyes closed.
ASHLEY: Between 2012 and 2017, nearly 20-thousand people died in crashes involving a distracted driver. And if your own safety isn’t enough reason to stop driving while distracted, here’s another one. It’s also illegal. That’s why cops are writing tickets to anyone caught texting while driving: they’re doing it to save lives.
CODY: So remember, if you text while driving, you WILL get caught. U Drive. U Text. U Pay.
Recapitulation Is the Debunked Theory That Embryos Repeat Evolution — https://curiosity.im/2HUkW9k (Ashley)
Today we’re gonna wrap up with a little mythbusting. You may have heard that a developing embryo kinda looks like it repeats the stages of evolution of its species. So like, while it’s growing, an embryo might look like a fish first, and then a more “evolved” human, and then look like an actual human. This theory is called recaputulation, and in case you didn’t know, it has been debunked. The most famous pioneer of recapitulation theory was a German zoologist named Ernst Haeckel, who famously said, quote: "Ontogeny recapitulates phylogeny," unquote. In layman's terms, that means the development of an embryo repeats the evolutionary changes its species took over the millennia to appear in its modern form. This form of recapitulation theory was called Haeckel's biogenetic law, and it that said each developmental stage of an embryo represents the adult form of one evolutionary ancestor. Haeckel's theory may have started as a misunderstanding of Darwin, who pointed out that vertebrate embryos look similar to each other early in their development, and used that as evidence of evolution. The important term there is early in their development — Darwin argued that they looked more and more different from each other the older they got. The funny thing is, on TOP of the fact that Haeckel’s theory didn’t really hold up scientifically, he also fudged his drawings. Seriously — he drew fish embryos alongside human embryos in a way that glossed over their differences and highlighted their similarities. Oops! Most scientists had dismissed these ideas by the turn of the 20th century, but in 1997, researchers used photographs of vertebrate embryos to show there isn’t actually any development stage where all vertebrate embryos are identical. This proved Haeckel's drawings wrong once and for all, and now you know the truth behind a major medical myth.
CODY: Read about today’s stories and more on curiosity-dot-com!
ASHLEY: Join us again tomorrow for the award-winning Curiosity Daily and learn something new in just a few minutes. I’m [NAME] and I’m [NAME]. Stay curious!