SciShow Tangents - Listener Mailbag

Starting point is 00:00:00 Hello, and welcome to SciShow Tangents, the lightly competitive knowledge showcase starring some of the geniuses that make the YouTube series SciShow happen. But this week, it is a completely non-competitive viewer mail showcase wherein those self-same geniuses answer your burning questions without Hank. Because he's, I don't know what he's doing. He's just not here. I didn't think about the non-competitive side of this. So we're not getting any points today. No points.

Starting point is 00:00:43 Nobody's getting any points today. The listener, they're getting the points in a way. The points that are us paying attention to them. This week, as always, we're joined by Stephan Chin. And I sourced some viewer questions specifically for the two of you. Oh my gosh. So here, instead of Hank asking completely inane questions, here's what the people really want to know. So, Stephan, at Valerie2776 asks, could Stephan talk about bulk buys? Just in general?

Starting point is 00:01:14 I suppose you could just answer this either yes or no, or however you want to take it. In general, I'm in favor of bulk buys, but I have a hard time with milk because I don't use a lot of milk. I use like half a cup of milk in a recipe, and then I'm like, I'm not going to drink any of the rest of this because I don't like milk separate from other things. Like, I barely tolerate it with cereal. But it feels like if you buy the small milk, it's like $3. And if you buy the gigantic milk, it's $4. So it feels terrible to buy the small milk.

Starting point is 00:01:50 But I know I'm not going to use the big milk. So even in bulk buy, life is hard. So this is the current bulk buy problem that you're trying to noodle through? Yeah. You could buy a cow. The other opportunity is you buy a gallon of milk, drink half a cup of it, and then drop the rest off at my house. We go through a lot of milk per week.

Starting point is 00:02:09 You never told me about your milk consumption habits. We got to make a spreadsheet. Maybe it could be some kind of chart that would automatically deplete as people were claiming certain amounts of milk. Hell yeah. Oh, this is a good question we were talking about the other day.

Starting point is 00:02:21 Sarah, can you freeze milk? And if you unthaw it, what happens? I, can you freeze milk? And if you breathe, unthaw it, what happens? I bet if you freeze milk and then you thought it becomes mostly watery, like the proteins would probably clump up because homogenized milk is basically describing how all the milk proteins are distributed throughout the water. And so like in 1% milk, then it's that,

Starting point is 00:02:44 that has to do with the quantity of protein which is why like two percent milk is creamier because it has more milk protein in there if you freeze it i bet it's kind of like freezing soda or something where all the carbon dioxide leaves and the syrup gets concentrated except instead of syrup getting concentrated it'll just be like weird milk curds that sounds really disgusting yeah So there you go, Stefan. You can't freeze milk. I bulk buy almond milk because it has a longer shelf life. And so as I occasionally want a smoothie or something, I've got a delicious liquid I can use for the smoothie. Okay.

Starting point is 00:03:22 That's all there is to say about that. Also joining us is Sari Riley. Sari, your viewer question is from at up bing king. And they ask, what does Sari think about yogurt? Oh, I like yogurt. Why is this the question for you? Do you know? Is this a joke of some sort that I don't get?

Starting point is 00:03:41 No, I have no clue why they're asking this. Okay. I have never been publicly pro or anti-yogurt, so I'm not having to defend any viewpoints. But you're pro-yogurt. I'm pro-yogurt. I'm probiotic. Get out of here.

Starting point is 00:03:57 Thank you. I feel like my usual yogurt combination is a plain yogurt or maybe a vanilla yogurt with fruit that I add to it and honey. I do raspberries usually. Yes. I like raspberries. I like blueberries. Sometimes I eat bananas with it. It like switches up the texture a little bit. Banana does not have the right consistency to be included in yogurt. That's my hot take. You went from being such like pro banana on this podcast to very. Yeah, now you hate bananas.

Starting point is 00:04:34 All right. Well, that person knew exactly the right question to ask you to get an interesting response. Amazing. And it was about yogurt. A lot of people asked you about music, which I think they were just mocking you. That's amazing. And it was about yogurt. A lot of people asked you about music, which I think they were just mocking you. That's expected. And I'm Sam Schultz and nobody bothered to ask me any questions. No way.

Starting point is 00:04:52 What's your viewer question? I didn't ask for any for myself. Oh, no. I should have probably. If you guys were good co-hosts, you would have asked for one for me to surprise me. Well, I didn't know what was happening. Every week on Tangents, we usually get together and try to one-up, amaze, and delight each other with science facts, and we're usually playing

Starting point is 00:05:07 for glory, but we're also usually keeping score and wearing handbooks from week to week. But this time, we're going to do something a little bit special, and we're going to take the questions that you guys have asked us on Twitter for the Ask the Science Couch segment and answer a bunch of them that we didn't do during those episodes.

Starting point is 00:05:24 So, we've each researched a few of them. Sari didn't do all of the work. She did a lot of the pre-research that maybe I borrowed heavily from. But this one's a little bit of all of us. Yeah, we're all the science couch today. Today we're all the science couch. Only has two cushions. So I'm lounging on the top of the science couch like a cat.

Starting point is 00:05:43 Across the back. Like laying on the back of it. Stefan, how about you go first? Okay. So my first question is from at patuna F. Do you really like tuna? That's my question. Do people get the same kind of sugar high slash rushes from the sugar like in apples?

Starting point is 00:06:00 This is an interesting question to me, but I am not a chemist. So bear with me as I hand wave some of that. It seems like we mostly chemically synthesize these, and some of them are derived, at least one of them is derived directly from plants. So aspartame is, I think usually in the US we have that, that's the one in the blue packets on like your diner table. But aspartame is made using fermentation, which I thought was kind of interesting. So like you have tanks and you have a bunch of bacteria or like two specific kinds of bacteria that poop out the two specific amino acids that you need.

Starting point is 00:06:37 That's where you, you isolate those amino acids and then do a bunch of chemistry wizardry on it. And it's just a bunch of sequences of like filtering and purifying and then like reacting it with something else, cooking it a little bit. Then you filter and purify, crystallize, filter, purify, crystallize. And then eventually you end up

Starting point is 00:06:55 with this final crystallized product that you can crush into the powder that you find in the little blue packets. And then there's sucralose, which is I think the yellow packets and that's what's in Splenda that is made from regular table sugar but then you do you i don't know i don't know how the chemistry works i have to be honest but they replace they replace uh several of the hydrogen oxygen groups with chlorine atoms and then that weird just happens to result in a thing

Starting point is 00:07:24 that is like heat stable so it works in like baking recipes and stuff um whereas some of these other ones don't and then you it tastes sweet and doesn't have any calories which is that's that's kind of the thing with all artificial sweeteners is that you're like chemically do synthesizing this thing and then it it still tastes sweet but it doesn't get digested by the body anymore. So then it has either very low calories or no calories. The other one that I looked into was stevia, which is the one that's derived from a plant. And I didn't realize this, but it's actually called, it's like the genus is stevia. So it's stevia rabadiana. You basically take the leaves, steep them in hot water, and then filter out the sweet

Starting point is 00:08:07 compound that you're looking for from that water and just concentrate it until you have the final product. So they're all produced a little differently, but basically to me, it's just a lot of chemistry magic and then you end up with this delicious... Most of them are way, way sweeter than table sugar, which I think is interesting. Most artificial sweeteners don't really increase your blood glucose levels because you're not metabolizing them. Or the ones that are metabolized are metabolized more slowly than table sugar would be or regular sugar. So you don't get the same blood glucose spikes that you would when you eat like a piece of candy or whatever that's not using artificial sweetener. And this might be another hot take because I know this is a very popular idea amongst the general population, but it seems like the idea that we get a sugar high at all is kind of a myth.

Starting point is 00:08:59 There was a study where they split children into two different groups and they said they were giving one group a sugary drink and one group an artificially sweetened drink. And then they had them drink the drink, and then they were playing in a room together with their parent. And the parents who thought that their children had drank the sugary drink perceived the kids' behavior as being way more hyper,

Starting point is 00:09:19 and they were hovering more closely and being more critical of the kids' hyperactivity and behavior while playing. But there wasn't really any difference between the two. It was just their perception of the child's behavior because they were like, oh, you had a drink. Now you're off the walls. But kids are just kind of hyper in general, it seems like, especially when you give them a delicious drink or they're playing in a room together. you give them a delicious drink or they're playing in a room together.

Starting point is 00:09:47 But then there's also been like, there was a meta analysis of 31 randomized controlled trials in adults. Their finding was that in the hour after eating sugar, that sugar consumption was related to decreased alertness and higher levels of fatigue. And so it doesn't seem like there's actually any kind of sugar rush that it's just maybe a placebo or that, you know. But there is a sugar crash. I cannot speak to that. If decreased alertness and higher levels of fatigue is a crash, then yes. That feels like after any sort of eating though, like that's how I feel. Decreased alertness, increased fatigue.

Starting point is 00:10:27 I ate a sandwich and then I'm in that state. So maybe that's just like you metabolizing something. Now, since I'm the boss, Sarah, you go next. So my first question is from two people, at Anna went home and at Vonilla Gadzilla. The question is, what's the deal with sneezing basically every single time I walk outside? I have this. Do you two sneeze when you go from a dark movie theater into bright light?

Starting point is 00:10:55 It's light-based, not allergy-based. That's what they're talking about. Yeah, that's what I thought it was. The photic sneeze. No, this doesn't happen to me. No, I don't experience this. This is interesting because statistically we match the overall population so it happens anywhere from one-fifth to one-third

Starting point is 00:11:14 of the human population might experience photic sneezing like stefan said it's also called the photic sneeze reflex or achoo because scientists love their acronyms autosomal dominant compelling heliophthalamic outburst syndrome oh boy gotta hand it to him that's a pretty good one and it's exactly what i've been describing which is uncontrollable sneezing in response to bright light especially in a transition from dark to light we We don't know a lot about it. We don't know comprehensively why it happens or what causes it, but we have narrowed it down a little bit. So as far as what causes it, it's a genetic condition. So some genetic conditions are controlled by a single gene, like sickle cell anemia, which is where your red blood cells are

Starting point is 00:12:02 sickle-shaped instead of round, and so you have trouble holding oxygen. That's like one gene mutation, and you can have that disease. But things like eye color take like tens of different genes to form the eye color. So like tweaking one of those genes will change your eye color a little bit, but you need a combination of them. The photic sneeze reflex is one of those that's controlled by multiple different genes. So there's a variety of genetic markers that we can look out for. Think not sponsored, but 23andMe claims that they can tell you whether you will do this based on your genetic makeup. So I don't know, Stefan, you did 23andMe. I think it told me I did not have that and I don't. So confirmed.

Starting point is 00:12:46 The only reason researchers are looking into it is because it could be dangerous if, for example, like I was driving a truck or I was a pilot and I sneeze while I'm driving because there's bright light. And so it could get dangerous. I have sneezed while I'm driving and it's scary. But the closest guess we have to its mechanism is nerve activation in your face. So there's a nerve in your face called the trigeminal nerve, also called the fifth cranial nerve. And it's really complicated. And to my understanding,

Starting point is 00:13:14 it controls like any sort of itchy feeling on your face or like if you feel sunburned or if you feel like your lips are chapped or if your nose tickles and the cranial nerves in your face and head are so intertwined in ways that we don't quite understand that activating one cranial nerve could activate another just by coincidence if they're like hypersensitive for some reason so this could be a case where like light activates your optic nerve really suddenly and then the trigeminal nerve gets triggered and then your nose gets itchy and then you sneeze.

Starting point is 00:13:53 So kind of like a chain reaction in some people's faces, but not others. So is your face itchier than other people's faces? I don't know. That's a good question. I feel like my face is fairly itchy. I think I'm pretty aware of if I have a tickle on my head and I need to scratch it. My first question is from Shauna Gecko. And Shauna Gecko asks, does milk really do your bones good or is it actually leaching calcium or not helping at all?

Starting point is 00:14:18 That's a good question. I feel like I've heard both. The milk ads really got to me as far as like milk gives strong bones, milk mustache. So I think that's why I like milk because I just drank it so much that I can't not like it. Do you drink a big glass of milk? Like will you do that?

Starting point is 00:14:34 Yeah. Especially with like cake or cookies or anything that feels like sticky in my mouth or. That's a special occasion though. You need milk then. Maybe I just eat a lot of desserts. Chicken cookies? Yeah.

Starting point is 00:14:47 So at the end of this recording, would you walk into your kitchen and pour yourself a big glass of milk? And that wouldn't be weird? I would need to eat something with it. I would pour myself a glass of chocolate milk, just plain, and straight up drink that. I don't know.

Starting point is 00:15:02 I'm one of these people who, when i eat cereal i pour the milk into the bowl first and then i pour a little bit of cereal in at a time so that i can eat you're the crispiest i want moist but very crispy. If it has too long to sit in the milk, it's no good. Why don't you just have a bowl of dry cereal and then eat the dry cereal and then take a drink of milk? You know, I've never tried that. I could also maybe just put milk in a spray bottle

Starting point is 00:15:39 and spray down my bowl of cereal. Just get a little... That's how a spray bottle would smell so bad. That sounds the worst. Brother, that's disgusting. I feel like you'd lose too much spraying the bowl of cereal.

Starting point is 00:15:50 You need to take a spoonful and then spray in your mouth. Yeah, yeah. So it really distributes the particles. A mouth mister. So will that help our bones? Okay, so...

Starting point is 00:16:01 Well, like you were saying the got milk thing I think must have been a very strong milk lobby because according to like official sources, you're supposed to drink three glasses of milk a day, which seems completely overwhelming. That's a lot. That's more liquid than I drink in a day of anything. I think you might be dehydrated then. But a Harvard paper that I found said that those recommendations were based on like really not very good studies that were too short to actually be able to tell. So I think got milk

Starting point is 00:16:28 has a lot to do with this. And it seems like the idea of milk leaching calcium from your bones comes from a Swedish study that looked at how much milk people drank in relation to how often they fractured bones and then how early they died. And the results, like, at first blush, look like as milk consumption goes up, the more your risk for fractures goes up, and you die earlier. So after one glass, so one glass is fine, but two glasses is, like, twice as bad. And then three glasses is, like, 100 times as bad

Starting point is 00:16:59 or something according to this study. Is this, like, per day? One glass per day? Yeah. Are you worried about yourself a little bit i've broken a bone and neither of you have so who knows no technically i broke how did you know that off the top of your head that we never broke a bone i feel like we've talked about it before okay but according to the british national health service that might have

Starting point is 00:17:21 less to do with the actual milk and more to do with the added vitamin A in milk. So it's like fortified with vitamins and minerals. So they weren't sure if in Sweden what the proportions were, but it's possible that there was more vitamin A than vitamin D in the milk and vitamin A leaches bones and makes them thinner. So if you have like more vitamin A than vitamin D, which helps you absorb calcium,

Starting point is 00:17:48 then your bones can be really thin. But the NHS also said that the study probably wasn't super thorough because it relied on self-reporting about how much milk everybody was drinking and it didn't have a lot of other details about their lifestyle, which would help them know

Starting point is 00:18:04 how much vitamin D they were getting otherwise, like if they're eating leafy greens or if they're going outside a lot of other details about their lifestyle, which would help them know how much vitamin D they were getting otherwise, like if they're eating leafy greens or if they're going outside a lot or if they're just always inside not getting any vitamin D. So there might be a lot of reasons that their bones were weaker. And that same Harvard paper I talked about earlier said that there are enough other sources of calcium, like leafy green vegetables and just like taking calcium supplements that you're better off just eating other stuff and not drinking milk

Starting point is 00:18:28 because milk is so like bad for you relatively in terms of like fat content. And I think even if you're not lactose intolerant, it's still kind of like rough on you a little bit. So in conclusion, I think milk is helping, question mark. But it's distinctly possible that if the ratio of vitamin A is wrong, then it either zeros everything out or it could be hurting your bone density. And you just get all the vitamin A that you need eating regular food anyway.

Starting point is 00:18:58 So milk is just like way too complicated to even bother with in my opinion. Just eat some broccoli and then you'll have your calcium and you'll be fine. Next up, we're going to take a short break and then we'll be back to answer more of your questions. all right stephanie i do another one oh i guess so so another question was from at crystal r99 how do whale ears work underwater i had some sense of this answer beforehand, but after looking into it, I'm like, this is still an area of research. There is a lot of this that we do not know,

Starting point is 00:19:58 but whales don't have the outer ear structures the way that we do. I think that's partially so that they can be real sleek and not have drag in the water, but they do have ear canals, but they are plugged with a waxy substance and other debris, and they apparently don't attach to the eardrum. And so they think the ear canals are actually just vestigial, and they're not using those to hear. And so the inner ears in whales work basically the same ways that ours do. There's some differences, but it's overall roughly the same mechanism. So whales do have some adaptations that help them get the sound to the inner ear in the water without having these outer ear structures. Their inner ear structures are outside of their skulls, which is different from us,

Starting point is 00:20:48 and they're down towards the jaw. Also worth pointing out, there's two broad categories of whales, which are toothed whales and baleen whales. It seems like we know more about toothed whales. They were able to do, I think, CT scans on dolphins, and they think that the bones of the jaw and the fatty tissues that surround the jaw are conducting the sound. And then there's a bit of fatty tissue that's also connecting the jaw to the ear. And so at least in dolphins, they were able to see that connection. And they've noted that the tissues, like those tissues that were connecting the jaw to the ear were similarly shaped to the outer ears of bats, which seems like a weird, because it's not serving the same purpose.

Starting point is 00:21:30 So I don't know why that would actually help in this case, but I don't know. They thought it was important. So I'm mentioning. Do baleen whales work the same way or do we just have no idea how they hear? Like the exact mechanism is less well understood, but I think the overall structure is roughly the same. But it does seem like the structures in a toothed whale are more geared towards capturing higher frequencies, which makes sense because they're the ones that echolocate versus the baleen whales were more geared towards lower frequencies, which sort of makes sense because they're doing the long distance whale song type stuff.

Starting point is 00:22:10 And there was another thing that I thought was really cool, which is sound travels way faster in water than in air, which I actually didn't realize. It's like four and a half times as fast. So because our heads are so small, it's hard for us to localize sound underwater because if someone's on your right, the sound reaches your right ear enough earlier than it reaches your left ear that you can differentiate that and tell that someone's on your right without seeing them. But underwater, because sound is traveling so much faster and our heads are too small, it's hard for us to differentiate between the time when it hits our right and left ear. But because whale heads are huge and because they've sort of moved the ears outside of the skull,

Starting point is 00:22:57 they're as far apart as possible so that they can do this localization underwater better. It's adapted for the speed of sound underwater, which is kind of cool. Got puny little grape heads. Yeah, yeah, grape heads. All right, we got a lightning round now. Sari, do your next one fast. Oh, okay.

Starting point is 00:23:15 So my second question is from at Flux Filter, what else physically makes ducks especially equipped for the water? If you gave a pigeon webbed feet could it technically swim the answer to that if you gave a pigeon webbed feet that's a yes for me not really oh no i feel like i feel like you're wrong yeah you're wrong so outvoted they won't even like as they currently are they won't drown If you gave them webbed feet, they could paddle a little bit better, but they don't have the adaptations that waterfowl do to help them stay waterproof,

Starting point is 00:23:52 which helps them stay light and float on top of the water. So specifically, ducks and pelicans and osprey and other waterbirds have something called a uropygial gland, which is kind of like its butt. When you see ducks preening themselves, so like sticking their beaks near their butt and then like rustling it in their feathers, they're spreading oil around, like a waxy oil that is secreted by their body and it fluffs up their feathers and it makes their feathers waterproof.

Starting point is 00:24:23 So when they're sitting on top of water, their feathers don't absorb that moisture and get weighed down. So in addition to paddling with their webbed feet, which has co-evolved in a lot of different bird species. So like webbed feet are important for swimming and aquatic birds. Having some sort of waterproofing is maybe even more important. having some sort of waterproofing is maybe even more important. So in addition to like having this coating, feathered animals, specifically animals with downy feathers can fluff themselves up. So sort of like you see birds fluff themselves up in winter. It has to do with the microstructure of their feathers, which has flexible barbs. I think they interlock into sort of a mesh

Starting point is 00:25:06 that traps warm air close to the bird's body and so that that can keep them warm but also it's sort of like like dumping a balloon onto the water it can't hurt them as they're swimming along if they have like a tiny bit of air trapped in these waterproof feathers as well i wish instead of like self-awareness and hands i have i could just swim around in really cold water just like rub yourself in butter and then float well moving on and it is from at a happy lee and they ask why do vitamin pills frequently have percentages over 100 of the daily intake this one seems like pretty cut and dry to me. And Sari already wrote about pretty much all of the research I could find too.

Starting point is 00:25:50 It was from Reddit. And it was a person who said that pills aren't a good delivery system for vitamins because you absorb vitamins when your stomach is digesting stuff and pills don't make your stomach digest stuff as much if at all. So you're not absorbing very much from a pill that you take. So they just have to pump it up with way more so that you actually absorb some appreciable amount of it. So that is fairly straightforward, but also it's probably partially because it just makes the vitamin sound better because it's a big number.

Starting point is 00:26:21 And we think that that's cool is my guess. And then I started looking into gummy vitamins because maybe those would kick you into digestion mode and they'd be better. That turned out to be a very contentious question because the vitamin community ain't a big fan of gummy vitamins, it turns out, because they are really hard to like quality control, I guess. And when you sample gummy vitamins, the amount of stuff in them varies extremely wildly. Some of them are gummies with like the stuff baked into them, but some of them are just gummies that are like dipped in a powder that has the vitamins on it. So it can all like fall off a gummy and you're just eating the gummy basically

Starting point is 00:27:00 by the end of the day. And the gummy technology is just not there to be both stable enough to last on shelves and good enough to make every gummy have the same amount of stuff in it. So maybe someday gummy vitamins will be the answer. But until then, we're just doing the best we can with our pills. That's interesting. I never thought about the gummy vitamin conundrum,

Starting point is 00:27:26 but it's true. Gummies are like the wild card of food. They're so uncontrollable. They're too fun and chaotic to be a good medicine delivery system. And now the show's over, because it's past time for us to go to bed.

Starting point is 00:27:42 If you like the show and you want to help us out, it's really easy to do that. First, leave us a review wherever you listen. It's super helpful and it helps us know what you think about the show. Second, tweet out your favorite moment from this episode. And finally, if you want to show your love for SciShow Tangents, just tell people about us. And also let us know what you think about a listener mail episode. Did you like me, Sam and Stefan, just talking about questions? Would you listen to more of them?

Starting point is 00:28:04 They're fun to make and we like hanging out. So we might make more if you like this. Thank you for joining us. I've been Sam Schultz. I've been Stefan Chin. And I've been Sari Reilly. SciShow Tangents is a co-production of Complexly and the wonderful team at WNYC Studios. It's created by all of us and produced by Caitlin Hoffmeister and myself.

Starting point is 00:28:23 And I also edit a lot of these episodes along with Hiroko Matsushima. Our social media organizer is Paola Garcia Prieto. Our editorial assistant is Deboki Chakrabarty. Our sound design is by Joseph Tuna Medesh. And we couldn't make any of this without you asking us questions on Twitter. It's one of the sincere joys of doing the show and I love to read them every week.

Starting point is 00:28:41 And also our patrons on Patreon. Thank you. And remember, the mind is not a vessel to be filled, but a fire to be lighted. But one more thing. But one more thing. There's an animal in the suborder Feliformia, which is basically the more cat-like carnivores, called Cryptopraca ferox.

Starting point is 00:29:14 Crypto meaning hidden, procta meaning anus, and ferox meaning ferocious. So you can look right below a cat's tail and see a butthole, but this animal and its cousins has flaps of fur-covered skin creating an anal pouch covering the anus and nearby glands.

Starting point is 00:29:33 Is there some way we could bring this back? I am sick of looking at my cat's butt. But what's the point? I think it lets them store up secretions so they can create a smelly thing in this pouch and then turn it inside out

Starting point is 00:29:48 and have a scent bomb or something like that. Okay. It's not just because the cat is modest and doesn't want people looking right up his butthole. No.

Starting point is 00:29:55 In fact, it's so that they can be even more grimy.

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