Something You Should Know - Unusual Ways Technology Affects You & The Strange Science of Sweat

Episode Date: July 12, 2021

You have probably noticed that aluminum foil has a shiny side and a dull side. Why? What’s the difference - and why do some recipes call for it to be either shiny side up or shiny side down? This ep...isode begins with an explanation. https://culinarylore.com/food-science:aluminum-foil-shiny-side-up-or-down/ How did radio technology help create the quartz watch? How did railroad technology reshape how we celebrate Christmas? How did the telegraph change the way we speak? These are just a few of the fascinating ways technologies have had an important impact on how we live. Ainissa Ramirez, is a material scientist and author of the book The Alchemy of Us: How Humans and Matter Transformed One Another (https://amzn.to/2UyQkCy) . Listen as she takes us on a journey through some of the fascinating technologies that continue to have a powerful impact on how we live our lives.   We humans are one of a very few species that sweat through our skin. As you probably know, the purpose of sweating is to help you stay cool. What is so interesting is how the whole system works. You have millions of sweat glands and what kind of climate you spent your toddler years in likely affected how many of your sweat glands were activated and how efficiently the work. And that’s just scratching the surface of the perspiration story. Science writer Sarah Everts has gone deep into the research on sweating for her book, The Joy of Sweat: The Strange Science of Perspiration (https://amzn.to/3AwyPTX) and she is here to explain what she found. Airplanes have oxygen masks in the event of an emergency. So where do they keep the oxygen? And why is it that they tell you to tug on the mask to begin the flow of oxygen? Listen because the answer to that question is really going to surprise you. https://www.scienceabc.com/eyeopeners/do-airplanes-really-carry-oxygen-for-the-oxygen-masks.html PLEASE SUPPORT OUR SPONSORS! Save time, money, and stress with Firstleaf – the wine club designed with you in mind! Join today and you’ll get 6 bottles of wine for $29.95 and free shipping! Just go to https://tryfirstleaf.com/SOMETHING Get 10% off on the purchase of Magnesium Breakthrough from BiOptimizers by visiting https://magbreakthrough.com/something Dell’s Semi Annual Sale is the perfect time to power up productivity and gaming victories. Now you can save what Dell employees save on high-performance tech. Save 17% on the latest XPS and Alienware computers with Intel Core processors. Plus, check out exclusive savings on Dell monitors, headsets and accessories for greater immersion in all you do. Upgrade today by calling 800 buy Dell, or you can visit https://dell.com/Semi Annual Sale Discover matches all the cash back you earn on your credit card at the end of your first year automatically and is accepted at 99% of places in the U.S. that take credit cards! Learn more at https://discover.com/yes Go to https://RockAuto.com right now and see all the parts available for your car or truck. Write SOMETHING in their “How did you hear about us?” box so they know we sent you! Learn about investment products and more at https://Investor.gov, your unbiased resource for valuable investment information, tools and tips. Before You Invest, https://Investor.gov. Visit https://remy-cointreau.com to learn more about their exceptional spirits! Visit https://ferguson.com for the best in all of your plumping supply needs! Learn more about your ad choices. Visit megaphone.fm/adchoices

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Starting point is 00:00:31 Today on Something You Should Know, why does aluminum foil have a shiny side and a dull side? What's the difference? Then, the amazing ways certain technologies have changed how we live. The railroad, clocks, glass cookware, even the telegraph. The telegraph actually had a hand in shaping language because sentences became compressed. If you went to a telegraph office they would tell you you had to keep your messages brief. If you look at
Starting point is 00:00:57 books written before the telegraph and books written after the telegraph you'll see that sentences are shorter. Also, airplanes have oxygen masks. So where do they keep the oxygen? And the science of sweat. Why we do it and where does it come from? What sweat is, is the liquidy parts of blood. If you drink something, it takes about 15 minutes before whatever it is that you're drinking ends up out on the surface of your skin as sweat. All this today on Something You Should Know. Bumble knows it's hard to start conversations. Hey. No, too basic. Hi there. Still no. What about hello, handsome? Who knew you could give yourself the ick?
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Starting point is 00:02:08 use in your life today something you should know with mike carothers well this is going to be a fun episode the strange science of sweat and how older technologies still impact your life today it's really interesting hi Hi, welcome to Something You Should Know, and we start today in the kitchen. And if you have spent any time in the kitchen, you've noticed that aluminum foil has both a shiny side and a dull side. And in cookbooks, you'll find recipes that say, cover with aluminum foil, shiny side down. Some cooks believe that it makes a difference which side is up or which side is down when you line a pan. Does it? No, it doesn't.
Starting point is 00:02:52 And here's how we know. First of all, the folks at Reynolds Aluminum say that the reason there is a dull side and a shiny side is simply the result of the manufacturing process. It's not intentional. It just comes out that way. They claim there is no significant difference which side you use when you cook or freeze or refrigerate food.
Starting point is 00:03:14 Secondly, the chefs at America's Test Kitchen did three tests where they cooked baked potatoes in foil, cooked mashed potatoes in a pan covered with foil, and heated water in a container covered with foil, and heated water in a container covered with foil, all in a regular conventional oven. They did each test twice, once with the shiny side facing out and once with the shiny side
Starting point is 00:03:36 facing in. And there was no difference. There is no difference. And that is something you should know. There's something called, and you may have never heard of this, I hadn't really heard of this before either, it's called material science. It's a real science, and people who work in this field do a lot of really interesting things that affect how you live your life. You'll understand this in just a second.
Starting point is 00:04:03 Anissa Ramirez is a material scientist. She's worked as a research scientist at Bell Labs and held academic positions at Yale and MIT. She's author of a book called The Alchemy of Us, How Humans and Matter Transformed One Another. Hi, Anissa. Welcome to Something You Should Know. Thank you so much. Great to be here. So explain briefly what material science is, because I think this is really fascinating. Well, it's the science of stuff. I call myself an atom whisperer, and I'm interested in how atoms move in the world, and then I try and convince them to do new things so we can make new materials.
Starting point is 00:04:41 So that's what material scientists do. And give me a real quick example of what you just said, of making moving atoms and making new stuff. For example, what? Your cell phone, that was made possible by material scientists. The fact that that glass is almost indestructible. Glass is usually fragile. Well, material scientists figure out how to make it so that it's strong
Starting point is 00:05:02 and so when you drop it, it doesn't break. That's kind of the things that we think about. Well, that's actually really cool. Sounds like a fun job. So one of the ways that material science has affected our lives and really changed our lives is how material science changed clocks, which is really interesting. So explain that. Clocks weren't always precise. I remember going to my grandmother's house and she would have a grandfather clock and it was always off. But we got better at the materials that are inside. First, they were very sophisticated springs and then they became quartz gems. And quartz actually vibrates if you put it in an electrical signal, and it vibrates a certain amount of time.
Starting point is 00:05:49 And you can use those vibrations as a way to mark off time precisely. So that's the material that's involved in making our clocks more accurate. And what's the story of how and who decided that instead of springs, we would use quartz to make clocks more accurate? Tell the story of that development. Oh, sure. Well, it ends up there was a Bell Lab scientist that most people don't know about. His name is Warren Marison. And he had a project where he was actually making a frequency generator. Radio was very popular back then. And sometimes radio stations were on the wrong station. And so they wanted to have a precise frequency generator so they knew where to broadcast their station. So he figured that out and he used quartz to do that
Starting point is 00:06:31 because you can get quartz to vibrate a certain number of times per second. And when he figured that out, he's like, well, look, if quartz can vibrate a certain number of times per second, maybe I can use this as a yardstick, if you will, for time. If I know it, if this, if I know this material will vibrate 10,000 times per second, I can count off those 10,000 vibrations and say, okay, that's one second. And so with that invention, he was able to create the first quartz watch. And so he was the inventor behind the quartz watch. And the, the weird effect that's going on with quartz is that it has a strange material property where that if you apply electrical signal to it, it wiggles.
Starting point is 00:07:11 It's called piezoelectricity. And that was found a long time ago by the Curie brothers. We know the name Curie with Madame Curie, but her husband and his brother, they actually found this effect long before she was married to him. And so quartz clocks replaced spring clocks. Is that a fair statement? Yeah, that's correct. So before quartz clocks, there were these springs. Crucible steel is the material that needed to figure out how to make steel springs that vibrated and were flexible precisely and uniformly. Before that, it was really hard to make uniform metals. See,
Starting point is 00:07:55 if you think about old movies, you would see blacksmiths and they would be folding over materials and they would make things like shoe horns and the like. And those were fine, but if you wanted to make something uniform, folding it over and heating and beading it really wasn't the best way to do that. So there was a gentleman whose name was Benjamin Huntsman. He figured out how to make very, very well controlled in terms of the composition of the steel. He figured out how to do that. And once he was able to do that, then we had very, very well made uniform metals and we can make springs that worked accurately. And so that's what was the heart of an early clock. And then later on, that was replaced by quartz. Because as accurate as those
Starting point is 00:08:37 springs were, quartz is more accurate. So that's why they replaced springs with quartz. And another area where material science really changed everything is the railroads. So explain that. Well, the railroads, we don't think about the railroads, but the railroads actually changed a lot of our experiences. First of all, long ago, before the railroads, we used to travel by stage coach. And it would take a long time to get from a distance like from New York to Boston. People wouldn't really do it. In fact, people wouldn't really travel more than 50 miles. If a son moved away from his family more than 50 miles, his mother might not see him again. So the railroads really made the country smaller because we were able to travel those distances to greater extents. The other thing
Starting point is 00:09:25 that the railroad did is it actually changed a holiday that we don't even think about, and that's Christmas. Now, Christmas used to be this holiday which was about meeting with the family and eating food. But around the Industrial Revolution, there were so many products that were available that the industrialists had to figure out a way to get these products and convince people to buy them. And so what happened is that Christmas was transformed into a gift giving occasion. And the way to get those gifts to people was through the railroad. So the railroad had a hand in commercializing Christmas.
Starting point is 00:10:00 And it was because of the steel, right? The steel tracks that the railroad ran on is what changed everything. Yeah. It's the rails. It's the rails. It's the steel. Why? We knew how to make steel.
Starting point is 00:10:13 Steel is a fantastic material because it's very hard. It's very tough. And usually you don't have materials that have both of those properties at the same time. And we had to figure out how to make it abundantly. Because at one point, you could make a small amount of it, enough to fill like a pot. But when Henry Bessemer figured out how to make tons of it, then we were able to make lots and lots of steel rails and have them go across the country. Now, before steel rails,
Starting point is 00:10:45 there were iron rails. And iron is a good material, but it had to be replaced every two years. But with steel, it could be replaced in 18 years. And so that means that you don't have to worry about the infrastructure. You can just build and build and build. If it's every two years, you have to replace these iron rails all the time. And so steel allowed us to forget about that for a while and build and build and build this infrastructure. So it was certainly the material that allowed us to build this huge network that connected the entire country. Were rails for trains built out of iron first and then converted to steel or we waited until steel? No, no. First, early rails were made
Starting point is 00:11:27 out of wood. Now that's not going to last long at all. A couple of rainstorms and you've got to replace that. So it was wood and then iron. And that was fantastic because it was better than wood. But again, it couldn't last very long. But then when steel came along, then you didn't have to worry about it for nearly two decades. So it was really, the railroads had been around for some time, but they really took off when we had better rails. When you think about the telegraph today, I mean, it's virtually a forgotten technology. And yet, at the time, it was such a big deal. And you think about the materials that went into creating this network of poles with wires going across all over the nation where you could send messages. It had to be huge.
Starting point is 00:12:18 Oh, that was mind-blowing. Because the fastest way that you can get information used to be by letter. And it would take maybe two weeks. So let's say you send a letter to your aunt, tell her about things that are going on. It would take two weeks before you hear back. But the telegraph changed all that. In minutes, you can hear from a relative. And that was amazing.
Starting point is 00:12:37 But the telegraph along the way actually started to have a hand in shaping language. Because it had a limitation of how much information could be sent. And so if you went to a telegraph office, they would tell you that you're welcome to use it, but you had to keep your messages brief so that other customers could use it. And what I discovered is that the telegraph actually had a hand in shaping language because sentences became compressed. If you look at books written before the telegraph and books written after the telegraph, you'll see that sentences are shorter. Now, there's many reasons for that, one of them being that America wanted to change the way it spoke English relative to the UK. But another was a
Starting point is 00:13:16 technology of the telegraph. It actually had a hand in shaping language. Well, I have a question about why things had to be kept so brief. But first, I'm speaking with Anissa Ramirez. She's a material scientist, and the name of her book is The Alchemy of Us, How Humans and Matter Transformed One Another. People who listen to Something You Should Know are curious about the world, looking to hear new ideas and perspectives. So, I want to tell you about a podcast that is full of new ideas and perspectives and one I've started listening to called Intelligence Squared. It's the podcast where great minds meet. Listen in for some great talks on science, tech, politics, creativity, wellness, and a lot more.
Starting point is 00:14:02 A couple of recent examples, Mustafa Suleiman, the CEO of Microsoft AI, discussing the future of technology. That's pretty cool. And writer, podcaster, and filmmaker, John Ronson, discussing the rise of conspiracies and culture wars. Intelligence Squared is the kind of podcast that gets you thinking a little more openly about the important conversations going on today.
Starting point is 00:14:27 Being curious, you're probably just the type of person Intelligence Squared is meant for. Check out Intelligence Squared wherever you get your podcasts. So, Anissa, what difference would it make if the sentences were longer or shorter, the messages were longer or shorter? Why was it necessary to keep things brief? Well, they wanted to keep the lines free for future customers. And also the telegraph, as wonderful as it was, sometimes it was unreliable and the lines could go down. So you wanted to make sure that your message, your dispatch made it to its destination. So they would say, keep it brief, because if the lines go down, at least they got some of the message, as opposed to if you keep a long sentence, you know, you can hear part of the sentence and not know what the full meaning was. So that was one of the reasons why people were encouraged to keep their messages brief. And so what about the technology and the materials used that made the telegraph
Starting point is 00:15:22 feasible? Well, the wires of the telegraph wires were initially made out of iron, but later made out of copper. And it relies on electricity going through that. And if you have electricity, how do you send a message? I liken it to water going through a pipe. If you're at one end of the pipe and I'm at the other end of the pipe and there's no way for me to communicate with you, how can I do that? Well, I can turn on and off the water to tell you, hey, Michael, something's going on. And if I get a little bit more sophisticated, I can turn it on for a short amount of time or turn it off and on for a long amount of time. And this could alert you that something is necessary on my end. And so that's what's going on with the telegraph. By using short and long pulses of electricity
Starting point is 00:16:06 and creating a code that equals each letter of the alphabet, this is how information was able to get shuttled across those copper wires. And so that was the basis for the telegraph. The carbon filament is one of those materials that really changed everything. So explain that story. Sure. A filament is a word that Thomas Edison came up with. that really changed everything. So explain that story. Sure. A filament is a word that Thomas Edison came up with.
Starting point is 00:16:31 And filament just means a very, very thin wire. And he was very much focused on figuring out the best wire for his incandescent bulbs, his light bulbs. And he tried thousands of different materials. And he eventually focused on carbon because carbon was able to glow very brightly. And that was the birth of the incandescent bulb. Now, what I also discovered is as light bulbs became abundant, it ends up that the type of light that surrounds us is not exactly the best light that we should have. Now, in Edison's day, people lived by the sun,
Starting point is 00:17:04 and then at night they live by his incandescent bulb. The sun generates a lot of blue light and incandescent bulbs are a redder light. But today you and I are surrounded by lights that generate a lot of bluer light. And this is not necessarily good for our health because our bodies have two modes, a growth mode and a repair mode. Our growth mode is where we have more growth hormones going through our bodies. And how our body knows to generate that is when it detects blue light.
Starting point is 00:17:31 So we're in growth mode most of the time. And as a result, there's a range of different health ailments that are bubbling up because of lights. So the carbon filament is something that we really don't think about. Light bulbs are things that we really don't think about. But now we're starting to see that they're impacting our health. The development and improvements in glassware, I mean, nobody really talks about that. You never hear about that. But really, glassware, the ability to have containers you
Starting point is 00:18:00 can see through, I mean, it was a big deal. Well, glassware is so important, particularly in science, because science is based on seeing and observation. And so it was very important to have a way to do that. And glass has been tremendous for that. We use that with glassware, such as beakers and Erlenmeyer flasks, but we also use it for lenses
Starting point is 00:18:21 and microscopes and telescopes. But for a long time, we couldn't get very good glass. You would look in a microscope or you would look in a telescope, and it kind of looked like 3D glasses, whereas the red side, there was a red side and there was a blue side. Now, there's no way that you can discover anything if you really can't see through the glass. So for a long time, people were trying to make better and better glass.
Starting point is 00:18:46 Now, glass was also necessary for glassware that goes in scientific laboratories. And that had some problems too, because if you poured an acid into older glassware, it would actually be eaten up by the acid. Well, that's no good, but you're going to have new problems if you do that. So it was really necessary for us to figure out how to make better glass. And it ends up that there was a woman, her name was Bessie Littleton. She came up with this idea that she needed a worked for Corning, and he was working on a new type of glass. He brought one of his samples home. She tried it out. She made a wonderful pie and different types of foods with it. This was actually the birth of Pyrex, so it became initially a way to cook better foods. But then later, Pyrex was used for scientific glassware, such as I mentioned, with Erlenmeyer flasks and test tubes and the like. So this idea of finding better bakeware is actually what gave rise to better science
Starting point is 00:19:50 equipment. So with glass cookware, why doesn't it break? I mean, if you took just a regular glass, drinking glass, and put it in the oven and turned it up to 500 degrees, it would shatter. So why doesn't cookware break? The secret element is boron. Boron is an element of the periodic table, again, that we don't usually think about, but it creates really, really strong bonds. So depending on how much boron you put in the glass, it's able to do different things. Some, if you have a certain amount of boron in the glass, the glass will be very, very strong so that it won't expand when you put it into the oven, and so you don't have to worry about it breaking. If you put less boron in it, it will be able to survive, if you
Starting point is 00:20:36 include other materials as well, it will be able to survive having acids in there. So the secret ingredient is boron, and these types of glasses are called borosilicate glasses. So like Pyrex measuring cups that you could put boiling water in, they have boron in them? They have boron. They're boron silicate glasses, and that's the reason why they're doing it, because of this element boron. One of the interesting examples of material science through the ages is sound, music, and how it has changed as the materials have changed. Well, what's so fantastic about sound is that it's very much linked to technology and particularly music. Early music was actually molded by early phonograph. The phonograph kind of looked like a huge horn that was connected to this
Starting point is 00:21:26 cylinder, but it couldn't pick up very, very soft sounds like guitars. And so if you listen to early music, you won't hear too many guitars. You'll hear loud music like horns and tubas and things like that. So the technology actually shaped music that we listened to. And the creator of the telegraph, sorry, the creator of the phonograph was actually Thomas Edison. And he made this wonderful device that was able to capture sound. In fact, people had thought this was a dream that you could actually capture sound. And this ability to store information, besides words on a page, but actually little pricks that are in tin foil, which is how the phonograph is made, actually put us on the path for other ways of storing things. And that put us on the path
Starting point is 00:22:13 for the hard disk. So music was actually part of the origination story for the hard disk. And the ability to store music really changed over the years because the materials changed over the years. You know, we had those big, very brittle, scratchy 78s. And then we had, you know, 33 RPM records and 45 RPM records and eight track tapes and cassette tapes and then the CD. And the CD was really, I think, a big deal in the sense that it was a digital way to store music. The CD was amazing because you can get to the specific song that you wanted right away. That was revolutionary because before that was the cassette tape. And if you wanted to get to a specific song, you would have to fast forward and stop, fast forward and stop. The CD was also kind of based on a similar way of thinking, meaning that it's made out of short and long dashes or short and long holes. And so it was a digital form of storing information. The phonograph was analog. The way that you spoke, like if I put my hand in front of my mouth and I
Starting point is 00:23:22 can feel the pressure wave, that is sort of what you would see on a phonograph. You would see big things when you say something like the letter P and you would say you would see smaller things when you saw when you said something like the letter S. So every bit of the space of sound was captured with the phonograph. But with the compact disc with CDs, it was digital. So there was a threshold for when a big dish, a big dash would occur and when a smaller dash would occur. So it was a big deal, but it was part of the evolution of sound. Well, it is amazing to realize how some of these early technologies and early materials were not only a big deal at the time, but were so profound that they continue to reverberate
Starting point is 00:24:07 and help shape our lives today. Anissa Ramirez has been my guest. She's a material scientist, and the name of her book is The Alchemy of Us, How Humans and Matter Transformed One Another. And you'll find a link to that book in the show notes. Thanks, Anissa. This has been kind of a real fun romp through history, so thank you for being here. Thank you'll find a link to that book in the show notes. Thanks, Anissa. This has been
Starting point is 00:24:25 kind of a real fun romp through history. So thank you for being here. Thank you so much. Since I host a podcast, it's pretty common for me to be asked to recommend a podcast. And I tell people, if you like something you should know, you're going to like The Jordan Harbinger Show. Every episode is a conversation with a fascinating guest. Of course, a lot of podcasts are conversations with guests, but Jordan does it better than most. Recently, he had a fascinating conversation with a British woman who was recruited and radicalized by ISIS and went to prison for three years.
Starting point is 00:25:01 She now works to raise awareness on this issue. It's a great conversation. And he spoke with Dr. Sarah Hill about how taking birth control not only prevents pregnancy, it can influence a woman's partner preferences, career choices, and overall behavior due to the hormonal changes it causes. Apple named the Jordan Harbinger Show one of the best podcasts a few years back. And in a nutshell, the show is aimed at making you a better, more informed critical thinker. Check out The Jordan Harbinger Show.
Starting point is 00:25:32 There's so much for you in this podcast. The Jordan Harbinger Show on Apple Podcasts, Spotify, or wherever you get your podcasts. Hey, everyone. Join me, Megan Rinks. And me, Melissa Demontss for Don't Blame Me, But Am I Wrong? Each week, we deliver four fun-filled shows. In Don't Blame Me, we tackle our listeners' dilemmas with hilariously honest advice. Then we have But Am I Wrong?, which is for the listeners that didn't take our advice. Plus, we share our hot takes on current events. Then tune in to see you next Tuesday for our Lister poll results
Starting point is 00:26:05 from But Am I Wrong? And finally, wrap up your week with Fisting Friday, where we catch up and talk all things pop culture. Listen to Don't Blame Me, But Am I Wrong on Apple Podcasts, Spotify, or wherever you get your podcasts. New episodes every Monday, Tuesday, Thursday, and Friday. Sweating, or perspiring, is something we all do. And so do horses, and monkeys, and hippos, and probably a few other animals. You've likely heard that the reason we sweat is to help us stay cool. Which is true, but it's so much more involved and interesting than that. As you're about to hear from science journalist Sarah Everts, who has thoroughly researched this topic for her book,
Starting point is 00:26:50 The Joy of Sweat, The Strange Science of Perspiration. Hi, Sarah. Hi, Michael. Nice to be here. So why is sweat and sweating so interesting and important to understand. So sweat is actually humanity's evolutionary superpower or one of them. The fact that we can cool off while in motion is something that we can do better than most other animals on this planet. So if you think about it, like one of the things that makes humans unique is that we're a naked ape. We're pretty much hairless, or mostly so. And because we're hairless, we have a lot of surface area on our body that can evaporate off sweat. And this is how we cool down. And because we can cool down off a huge surface area, we can do all sorts of things
Starting point is 00:27:47 in really hot temperatures. We can go foraging in the middle of the day. We can run marathons. And this has actually been this huge evolutionary advantage. So if you think about our predecessors, if you're hunting, right, most of the prey that we would be seeking runs faster than us. They can sprint way faster. But they have to stop to cool down because dying of heat stroke is a really terrible way to die. But because we can cool down while we're running, we can catch up with that prey and effectively force them to run again and run again and run again until they are so weakened by heat stroke that it's easy to kill them or they actually just die of that. And, you know, if you consider a dog, dogs cool down by panting, right? And they're
Starting point is 00:28:39 doing the same thing. They are evaporating a liquid, but only off the surface of their tongue, because that's the like only ha off the surface of their tongue, because that's the like only hairless area of their body, whereas we have our whole bodies. And also just to go back to dogs, they're evaporating saliva. We are evaporating sweat. And if you like look at other animals, this sweating evaporation is one of the most efficient ways to cool down. But if you don't have sweat glands to do that, you have to rely on other bodily fluids. And I'd argue that saliva is one of the least gross other bodily fluids you could rely on. Some animals like seals urinate on themselves to get wet enough to evaporate that heat away.
Starting point is 00:29:23 Vultures poop on their own legs. Honeybees vomit on themselves. So it's kind of amazing that we have a heat control sort of mechanism embedded in our own skin, like millions of little machines that are devoted to keeping us cool. Interestingly, though, we don't all sweat the same. Some people seem to be get real sweaty and other people don't seem to break a sweat. So what's the difference there? Certainly your genetics play an important part. Some people have more sweat glands. So your average person has between two and five million. I actually got my sweat glands counted and we've only known each other a few minutes, but I feel comfortable to say that I have three your average person has between two and 5 million. Um, I actually got my sweat glands counted and
Starting point is 00:30:05 we've only known each other a few minutes, but I feel comfortable to say that I have 3 million. Um, so there's like, thank you. Uh, so there's like the number of sweat glands that you have. There is another genetic component, like how fast that sweat, um, comes out of your glands, like the rate, the flux of sweat. And then there's also, you know, the triggering, you know, how quickly does your body react to, you know, a hotter core. But then there's also nurture. So you are born with all the sweat glands that you're ever going to have on your body, but it's in your toddler years that they actually all become either fully activated or not. And so some researchers are looking into the impact of
Starting point is 00:30:52 environment. So where did you spend your toddler years? Was it in a cold climate? Was it in a hot climate? And based on that, that may affect how many sweat glands got activated and how efficient they are, because pretty much everybody is sweating all the time. Even if you're not boiling hot, your sweat glands are making tiny, minute adjustments to your core temperature by releasing tiny amounts of sweat. And then, of course, if you go for a run or you're out in the sun, you get really hot and they start releasing more. But, you know, people who have grown up in very hot climates often have more sort of efficient sweating. So they may not look like they're sweating, but certainly they are because otherwise they would be totally miserable. So the sweat that I sweat probably I'm guessing started out as something I drank. It's the water in my system that somehow gets to my sweat glands and then comes out as sweat. Is that a fair assessment? Yeah. So effectively what sweat is, is the liquidy
Starting point is 00:32:00 parts of blood. So anything that is circulating around, yeah, yeah. Because the way that your sweat glands find something to put out on the skin is they effectively recruit what's called interstitial fluid. So you got blood, right? And then if you were to open up your body, your body's wet inside, right? All your organs are moist. And that moist stuff is called interstitial fluid. And it's, yeah, it's blood minus the big red blood cells, the platelets, the immune cells, and your sweat glands just source sweat from that interstitial fluid. Ooh. Sorry. But you're totally right. If you drink something, it takes about 15 minutes before whatever it is that you're drinking ends up out on the surface of your skin as sweat. Well, that kind of implies that we need to drink a lot because if we drink something and 15 minutes
Starting point is 00:33:02 later, it's coming out as sweat, it means we need to replenish that. I mean, what mom said about drink lots of water seems like pretty good advice. Yeah, exactly. But I'd say, you know, drink to your thirst, right? We don't need to overhydrate. And if you drink too much, you could have this horrible condition called hyponatremia, which is when you drink too much and you swell your body up and you can actually die from swelling your spinal cord off. It seems like you'd have to drink an awful lot of water for that to happen. Isn't the bigger problem that we're not drinking enough water, not that we're drinking too much water? You're wrong about that. So if you look at marathons and people have done this
Starting point is 00:33:51 research, more people have died of hyponatrenia than they have of heat stroke. And that's because there's this constant push to drink, drink, drink, drink, drink, which is good. But we have evolved over many, many, many years to have our thirst tell us when to drink. We also sweat when we're nervous. It has nothing to do with, or maybe it has something to do with being hot, but that isn't the root cause of it. We're just nervous. Why is that? Good question.
Starting point is 00:34:23 So we're activated to sweat from two ways. One is obviously temperature, but another one is sort of hormones like adrenaline. So if you're nervous, that can also open the floodgates. So your sweating glands can be triggered to open two different ways. Well, I know I've heard that there's, you know, two kinds of sweating and that there's two kinds of sweat. There's the sweat, the perspiration that you give off to cool down. And then the nervous sweat is a whole different kind of sweat, is it? Oh, so there are two different kinds of sweat glands. And I'm really glad you asked about that because one is the
Starting point is 00:35:05 liquidy water stuff, right? The stuff that we've been talking about, it's called like an eccrine sweat gland and its job is to cool you down. And that sweat is the liquidy parts of blood. Whereas there's another sweat gland that appears anywhere where you grow hair during adolescence. And its sweat is actually pretty waxy. And wherever hair grows during adolescence, including, of course, your armpits, that sweat starts getting released during the teenage years, and it's responsible for morphing the armpits into stink zones. And that sweat is waxy. It's quite a lot more similar to earwax than to the salty wet stuff that we're, you know, producing to cool down. And it turns into stinky stuff because the bacteria that live all over your body, they love to eat it. And when they eat it, they metabolize it. And what they release
Starting point is 00:36:01 is really stinky. And so, you know, the good news is you're not stinky because your sweat actually stinks. You're stinky because bacteria living in your armpits are eating your sweat and turning it into stinky stuff. So good news, bad news, don't know. Why is sweat salty? That's because our blood is salty, right? And so the salt is actually kind of an incidental tag along. We don't need the salt to cool down. We just need water to evaporate away the heat.
Starting point is 00:36:34 But because our bodies are salty oceans, the salt comes along for the ride. And so we've often heard that you, the commercials tell you that you need to drink not just water, but you need to replace your minerals, your salts and things because you sweat that out. Is that a valid claim? I totally agree with the claim that we need to replenish our electrolytes. I typically don't buy the products, though, because so think about the amount of salt that you lose. Oh, and by the way, your sweat glands are desperately trying to retrieve salt. So they really try to keep the salt in your body. And actually, the amount of salt that comes out in sweat is lower than the, you know, the saltiness of the water inside your body because your body is trying so desperately hard to, you know, keep those electrolytes on the inside. But I think we probably can all admit that we have tasted sweat at some point in some capacity and it's still pretty salty and you can't imagine or I couldn't imagine drinking a whole cup of that. And so if you need to replenish your electrolytes, you need to do that by eating salty foods or foods with salt in it, not by drinking it
Starting point is 00:37:53 because you can't actually get all those electrolytes back into your body that way. It's unpalatable. And so if you want to drink a sports drink, go right ahead. But the amount of sugar that's added is high, and the amount of electrolytes that you actually replace is low compared to what you've actually lost in your sweat. So let's talk about the connection between sweat and human attraction. Because I've heard there's a connection. I don't really understand it. I don't get how somebody's smells could really turn you on or off that much. So you're not a candidate for the sweat dating events that sometimes happen around the world? Seemingly not. how we smell is that, you know, whether we like it or not, we do have an odor and we recognize the
Starting point is 00:38:48 odor of those around us. So for example, you know, parents can identify their newborns based on smell just, you know, hours after birth for the mother and a little bit later for the other non-birthing parent. And siblings who haven't seen each other for years can identify their sibling's odor. And so we have an odor print, whether we like it or not. And law enforcement has long relied on dogs, for example, to sniff out individuals based on our odor print. So we do have an odor. And in that odor, there's all sorts of interesting pieces of social information that we share with one another. So if you're anxious, as you had mentioned a little bit earlier, you know, people sweat a stinky kind of odor when they're stressed out. Law enforcement have long said that people come
Starting point is 00:39:37 into interrogations smelling like themselves and leave all smelling super anxious. Like there's this dominant thing that comes out and, you know, t-shirt experiments done by scientists, you can identify whether somebody has sweat just, you know, due to exercise versus whether they've been stressed out. But in terms of romance, I think that there's like a couple of things at play. Clearly, you're going to smell the body odor of your romantic partner at some point or another, and it's going to be a make or break moment, right? So, you know, just, you know, on the surface, you're going to have to, you know, be comfortable with that odor. But of course,
Starting point is 00:40:17 everybody loves to think about pheromones, right? You know, is there something in our sweat that is making somebody attracted to me? Is there a way to do that? And, you know, in the animal kingdom, pheromones certainly exist. So, for example, pigs are my favorite. The male pig will breathe heavily on the female, and there's a pheromone called androstenol and androstenone, which if she sniffs that and if she's in heat, she will immediately spin around and raise her rump sort of in a universal physical sign that it's time to start a family. Moths do the same thing. The female will release a pheromone called bombacol. If a male nearby smells it, he will immediately zoom to herd a mate. It's like the perfect definition of a booty call. When you know that,
Starting point is 00:41:13 it's kind of hard to imagine that that exists in humans. And it'd be kind of alarming if it did, because can you imagine actually being able to, you know, spritz something out and, you know, ultimately immediately get a booty call? But researchers have found that we are attracted to those of others who have immune systems that are slightly different enough that any progeny that we have will have a really robust immune system. And if you think about it, that, you know, is really beneficial to the human species. You know, for most of human history, it's been pathogens that, you know, kill us. And so if you can be attracted to somebody who's got a different enough immune system so that, you know, the combination of immune systems, you know, is really strong, then great. Your child is going to probably survive to adulthood and maybe pass on your genes.
Starting point is 00:42:11 For as long as humans have been human, we've been sweating. And so theoretically, we've also been stinking from our sweat. And I guess forever, it never really bothered anybody to the last hundred years or so. And now there's this whole industry, the antiperspirant industry and the deodorant industry that's convinced us that we shouldn't sweat and that if we do sweat, we don't smell. So where did that all come from? Around the turn of the 20th century is when deodorants and antiperspirants are first being invented and brought to market. And at the time, it's the Victorian era. And people don't want to be talking about sweat. And also, quite frankly, they don't think they need to control their body odor. They think that washing with soap and water and maybe applying some perfume is good enough for me. Thank you very much. And so it actually took a very clever marketer called James Webb Young to figure out a way to put the fear of stink, particularly in his case, in America. And in the 1919s, he works with this woman named Edna Murphy,
Starting point is 00:43:27 or she hires him to market her product, a product called Odor Oh No. And he effectively discovers that, you know, everybody has heard of these sorts of products, but they don't think they need it. And so his strategy is to tell women that not only do they stink, but they stink a lot and people are talking about them behind their backs. The strategy is called whisper copy, by the way. And that not only are people gossiping about them, but this ultimately is going to mean they're not going to find themselves a husband. So, you know, it's 1919. And it's amazing because one of his advertisements, which appeared in Ladies Home Journal and effectively said, you know, within the curve of a woman's arm, you know, secrets too dark to, you know, to be uncovered, something like that.
Starting point is 00:44:18 People canceled their subscription to Ladies Home Germinal because they were so offended that he was saying this to women. Yet simultaneously, sales of odor oh no skyrocketed. And, you know, soon many other companies who are also trying to market deodorants and any purse prints were borrowing from this. So, you know, you'd see headlines, beautiful but dumb. She has never learned the first thing about body odor control. And finally, in the 30s, when they've exhausted all the advertising to women, they're like, oh, we need to make more money. Let's target men. But because they've spent over a decade
Starting point is 00:44:59 presenting deodorants and antiperspirants as a female product, they have to go out of their way to make deodorants and antiperspirants very masculine. And so some of the early entrepreneurs are doing things like marketing them in whiskey jugs. They're getting sports people to advertise them. And the thing that they're kind of preying on is men's fear of having a job, right? It was the Great Depression at the time. Men are worried about losing work. And so instead of saying they're not going to find a mate for life, they're like, you're going to lose your job if you're stinky in the workplace. So yeah, I do think that, you know, it's nice to be able to control your body odor. I sometimes wear these products,
Starting point is 00:45:45 but I'm always really cognizant that this is something that marketers have really instilled in my culture over the past hundred years. I've always wondered how deodorants work, and maybe more so I've wondered how do antiperspirants work? Because if perspiring, if sweating is such a natural and necessary thing, why would you want to stop it? But I can understand why you would want to stop some of it.
Starting point is 00:46:14 But how do they work? What's the mechanism that they are effective? Great question. I'll start with deodorants. Deodorants work by being effectively an antiseptic. So they kill the armpit bacteria that would eat the waxy secretions block that sweat from coming out at all and block the buffet for all those armpit bacteria. So what did you find doing the research for this? What did you find that was really surprising about sweat? I'd say there's two quick things that I'll, you know, try and be short about it. The first is that fingerprints are actually just sweat prints.
Starting point is 00:47:05 So anything that's circulating around in your blood gets left behind in a fingerprint. And, you know, law enforcement has typically, you know, picked up a fingerprint to try and see how it looks. But now chemists are figuring out how to analyze, you know, the microscopic amounts of chemicals left behind in that sweat print, right? And they can tell, I went and had my fingerprints analyzed and, you know, you could tell that I'd had a cup of coffee, there's caffeine coming out. And the researcher who did this, Simona Francesi at Sheffield, she's been working with law
Starting point is 00:47:41 enforcement. And, you know, you can also tell if somebody has snorted cocaine, whether they have been drinking alcohol just from the chemicals left behind in a fingerprint. So, you know, this is just in the early stages of research. But I do think a lot about, you know, the future of surveillance because, you know, we worry about, you know, the DNA that we leave behind in, you know, our hairs or, you know, on our spit on a coffee cup or whatever. And I think this is going to be another issue along the same lines. And I think the other super interesting thing is that there's an artificial sweat industry. So even though, like, we arguably produce enough sweat, thank you very much, there are many researchers who need to have synthetic sweat in their labs to do their work. And so everything from textile companies who want to make sure that the dye in their t-shirts doesn't leach out into
Starting point is 00:48:39 somebody's armpit, or smartphone manufacturers want to make sure that the electronics on the surface of the phone can deal with sweaty fingers or watch manufacturers are worried about nickel leaching out. So people use synthetic sweat to do all sorts of funny experiments. And it just makes me laugh to think that around the world, little bottles of synthetic sweat are being shipped about all while I'm sweating up a storm out in the sun. Well, I never knew there was so much to know about sweating, but since it's something we all do, it's kind of interesting to hear what it is that's going on and why it's going on. Sarah Everts has been my guest. She's a science journalist, and the name of her book is The Joy of Sweat, The Strange Science of Perspiration.
Starting point is 00:49:27 And you'll find a link to that book in the show notes. Thanks for being here, Sarah. Appreciate you coming on. Thank you so much. You know, when you fly, the flight attendants do that little demonstration that includes what to do if the oxygen masks come down in an emergency. Well, have you ever wondered where on the plane they keep all that oxygen? Well, they don't. There are no big tanks of oxygen. That would be dangerous, would weigh a lot, and take up a lot of room. Instead, what really happens is there is a chemical reaction that creates oxygen. The chemicals are barium peroxide, sodium chlorate, and potassium chlorate. And you know that part in the demonstration when
Starting point is 00:50:12 the flight attendant says you need to pull down on the mask to release the flow of oxygen? Well, what really happens is that tug on the mask triggers a firing pin that initiates that chemical reaction. The byproduct of that reaction is oxygen. There's enough for about 20 minutes, which is enough time for the pilot to bring the plane lower so you can breathe again. And that is something you should know. I always appreciate when people take the time to leave a rating and review of this podcast on Apple Podcasts. If you have a moment, it takes no time at all, and it helps us with our rankings. Believe me, it helps us. So leave a rating and review if you would. I'm Mike Carruthers. Thanks for listening today to Something You Should Know.
Starting point is 00:50:57 Do you love Disney? Do you love top 10 lists? Then you are going to love our hit podcast, Disney Countdown. I'm Megan, the Magical Millennial. And I'm the Dapper Danielle. On every episode of our fun and family-friendly show, we count down our top 10 lists of all things Disney. The parks, the movies, the music, the food, the lore. There is nothing we don't cover on our show. We are famous for rabbit holes, Disney themed games, and fun facts you didn't know you needed. I had Danielle and Megan record some answers to seemingly meaningless questions. I asked Danielle,
Starting point is 00:51:31 what insect song is typically higher pitched in hotter temperatures and lower pitched in cooler temperatures? You got this. No, I didn't. Don't believe that. About a witch coming true? Well, I didn't either.
Starting point is 00:51:42 Of course, I'm just a cicada. I'm crying. I'm so sorry. You win that one. So if you're looking for a healthy dose of Disney magic, check out Disney Countdown wherever you get your podcasts. Hi, this is Rob Benedict. And I am Richard Spate.
Starting point is 00:52:01 We were both on a little show you might know called Supernatural. It had a pretty good run, 15 seasons, 327 episodes. And though we have seen, of course, every episode many times, we figured, hey, now that we're wrapped, let's watch it all again. And we can't do that alone. So we're inviting the cast and crew that made the show along for the ride. We've got writers, producers, composers, directors, and we'll of course have some actors on as well,
Starting point is 00:52:28 including some certain guys that played some certain pretty iconic brothers. It was kind of a little bit of a left field choice in the best way possible. The note from Kripke was, he's great, we love him, but we're looking for like a really intelligent Duchovny type. With 15 seasons to explore, it's going to be the road trip of several lifetimes.
Starting point is 00:52:49 So please join us and subscribe to Supernatural then and now.

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