Dear Hank & John - 366: Just Science Day (w/ Deboki Chakravarti!)

Episode Date: April 3, 2023

What does water smell like? Did bipedal dinosaurs get back pain? Is my perception of time related to my heart rate? Does getting fresh air when you're sick actually doing anything? Are orange peels airtight? Why can't I smell ants? Why can't humans drink river water anymore? Deboki Chakravarti and Hank Green have answers! If you're in need of dubious advice, email us at [e-mail] us for monthly livestreams and an exclusive weekly podcast at patreon.com/dearhankandjohn.Follow us on Twitter! twitter.com/dearhankandjohn

Hello and welcome to Dear Hank and John. Or, as I like to think of it, Dear Deboki and Hank. It's a podcast where two brothers and sometimes two friends answer your questions, give you a kiss advice, and bring you all the week's news. From both Mars and AFC Wimbledon, but probably not Wimbledon today, Deboki. Do you know why bacteria are so bad at math? No. Well, let me give you a hint.

Do you know how a bacteria would multiply? It would divide. And do it that way. Can't multiply by dividing. Got it. I got it. That took me a second. I was mostly worried that I was going to be wrong about bacteria.

My impulse anytime anyone asks me a question is like, I'm going to be wrong. Oh, no. Yeah. I'm on the right podcast. It's a huge, it's a huge problem when you're like the science guy. And then it's like, when you get something wrong. Yeah. Well, let's just all admit that everyone is fallible.

And that also sometimes I totally forgot the difference when a pro-carrier in the UK. It happens. It doesn't happen as much since we started doing microcosmos. That's true. That has helped me. I think I realized how little I knew about microbes ever since I started working on microcosmos. But then I also working on microcosmos has helped me realize how little everyone knows about microbes.

Yeah, we'd like to make a video about this thing. It's like, enjoy your two-minute long video. Because everything humans know about it. Yeah, exactly. So for people who you probably have heard Deboki's name at the very least in the credits of this podcast because Deboki is our editorial assistant, which means that she looks at questions and then we every, like week before the podcast, Deboki and I talk about science questions to pick out which ones we might answer and Deboki does a bunch of research to see if maybe there's something interesting

to say about these topics. And during those phone calls, we make a podcast for just the two of us that I find very entertaining. It's very good. It moves fast and we get through like two questions, but it's very good. It moves fast and we get through like two questions, but it's very good. We're just talking, we're like, this can't be right. There's a lot of it.

Someone must have done this study before. Someone must have blindfolded a dolphin and taped its mouth shut and stuck a fish in to see if they can smell somehow. Yes, that is a conversation we just had. And also, Debuki works on a bunch of other stuff, hosted Crash Course Organic Chemistry and works on microcosmos, journey to the microcosmos YouTube channel, and is the host of the Tiny Matters podcast, which you can also listen to probably in the very app you're listening to this on, if you'd like a little bit more of that.

I'd guest hosted recently, so you can go listen to my episode. Yeah, it was a lot of fun. Hank answered my questions for once, so it was a good time. So we've got a bunch of science questions and it's just science day. That's what we get to do today here on deer hank and Deboki because that's what we're good at. And we don't have John here to like analyze Huck Finn or whatever. Yeah. Yeah, I can't do that.

I could try, but that is not my area of expertise. The blindfolding dolphins. Yeah, definitely. I'd be like, I can tell you what Mark Twinn would do if you blindfolded him and put him in a pool. What, how did we meet? Just because you're a YouTuber? Yeah, I think just because I started working for you, I think that's what happened.

I think the first time we met was when I interviewed for this job. Yeah, but I had no one of you before then, because probably because of Nicole. Yeah, probably because of Nicole. I sent and like just peripherally through that. Yeah. Just Nicole was a producer on Crash Course

who was also a YouTuber. That's pretty awesome. In quotation marks, like what was a YouTuber or is a YouTuber anyway? Yeah. Made YouTube videos. Yes, we do things that YouTube has managed to take from us and put on. Like when I say take from us is because we gave it, we gave YouTube our things and I'll do with it what you will.

I will. I will sign the implicit license that every creator signs when they upwards of video without knowing that you're signing it. So I was just get started here and this first question is from I think Mace, but maybe Macy, a deer hankered the bokeh. How do you smell underwater? I just watch a clip from the BBC's The Maiden game about flatworms. Very cool. And it says flatworms are blind, but they find their way by smell. Like, how could you smell underwater?

This also begs the question, what does water smell like, smell you later, Mace? I like the, I wonder what water smells like. I feel like there's a touch of what color is air to the question. Yeah. Well, air has a color. I mean, does it? It does.

Do you want to know? Yeah. I think, John, I think that we've had, the view and I have had this conversation before. Yes, yes. If you would like to see the color of air, go outside and look up on a day that isn't cloudy. Yeah.

What else is it? There's nothing there, it's just air. So just stick your head into the ocean and that is the smell of water. That's the smell of water. Sniff it up and what it smells like is pain. Yeah, it will not smell good. Please don't do that, people.

Yeah, I mean, like we've all, I assume that we've all had water go up your nose. The thing also is that your nose is always wet. Like there's always moisture in your nose. Yeah. So just like the smell of air, the smell of wet has to be something that you just filter out or doesn't get detected. Yeah, our brain is just like ruled out whatever the smell of our own mucus is. Unless it's really bad, I guess. Yeah, we've all had a nose. So we know sometimes suddenly there is a smell.

Just a little, a little one. And also every morning when you wake up. Yeah. Gross. Yeah. Bodies. The pain is because of osmotic pressure, I think. So like you put salty water up your nose,

and salt will go into your nose like across the cell membranes. And if you put fresh water up your nose, and the salt will come like across the cell membranes. And if you put fresh water up your nose, then the salt will come out of your cell membranes. I see. And both of those are unpleasant. But if you put the right salinity of water in your nose, it's basically undetectable. Just like having snot in your nose is basically undetectable, except that it's I see. Warm or whatever it would be coming out of your netty pot. Yeah, which netty pot seem to be a bad idea. Yeah.

I've never done it. And it scares me people keep having problems with it. So I just wanted to not be an endorsement. We're really hard on the non endorsements right now. Don't stick your head into water to smell it. Don't just like really deeply inhale a bunch of sea water. Do I guess that is a question? When you use a nettie pot, can you smell the water in the nettie pot? I bet. Oh gosh, I found out a fact. So I don't know if, have you ever had an IV?

Yes. So when you first get an IV, sometimes they will flush it with saline. They'll like, they eat you with like a syringe full of saline water. This is a little bit terrible, but it's true. And so I guess we'll just live with it. Okay. And sometimes when that happens, patients will report that they can smell it. And that's very weird, that something is being put into your veins and then you can smell it, especially

because it's saline, it's just salt water. And so that's what, when you said can you smell the nutty pot water, that's what it made me think of. But you're not actually smelling the salt water. What is happening is that that saline was sitting around in that plastic syringe for a while, possibly quite a while, and some of the volatiles from the plastic dissolve in the saline, and then it goes into your blood, hits your lungs, evaporates into your lungs, and you breathe it out. Oh. into your lungs and you breathe it out. And we know, like, I fact check this six ways from Sunday. It seems so wrong, but it is the correct, and if you prep a saline flush, and then use it immediately,

this to smell does not happen. It only happens with plastic syringes that have been sitting around for a while. Wow. Oh, wow. And so, like, they've been able to, like, do you know, like, where people, like, tracking these compounds? Like, were they measuring what was coming out of people's mouths?

No. But they just, like, they know that this is the thing. Yeah, yeah, yeah. It was, like, any nurse will have heard this from their patients, that, like, some patients. And not everyone notices it, but there's like this sweet smell of from getting the saline flush,

which I told that to, I get a regular infusion for my colitis, and I told that to my nurse, and I came back in recently and she was like, I've been telling everybody, I'm like, you shouldn't do that in this town, people hate plastic in this town. Yeah.

I hope she's citing you. I hope everyone is like that is my anchoring fact for the day. Uh-huh. She was like, are you the one who told me? And I'm like, I am. That was me. That's what I do for a living. I take full facts.

Yeah. Once you start, you just can't stop. Yeah. I mean, you guys have to hear about this horrible thing I learned. Yeah, they did this study like ages and ages ago. And like, I don't know, it was like 10 plus years ago. And just like hasn't spread around. And I think it's because people don't want to say it.

It's like, you don't want to like eat out of a like a plastic thing you microwave that in because it might taste plasticky. But you said it was like a sweet smell? It kind of smells sweet. Yeah. It's not too bad. No, it's not.

But I am like, I don't know if I want that stuff in me. Yeah. I guess it evaporates quickly. Otherwise, you couldn't smell it. Yeah. If it's happening pretty fast, it sounds like. Yeah. Weird.

What are you saying? So weird. So weird. Oh. But so I'm confident that I can't smell underwater because I'm not set up for that. Yeah. But you're not probably. But like flatworms, flatworms is just like what you mean by smelling is basically tasting. It's just probably I was looking up like what their organs are

I think they're supposed to have some little organs in their heads that help out with smelling But I couldn't find too much more about how they work But there are a lot of very fun like animal smelling methods like for a while researchers thought that like like animal smelling methods. Like for a while, researchers thought that like, maybe mammals aren't great at smelling underwater, but they found some that are. So there's the star-nosed mole, which actually the way it breathes a smell, it's so cool.

It blows bubbles out of its nostril and then like sucks them back in to smell. And they were able to do this to like follow earthworms and fish sense. So like I don't know how they underwater. They're like underwater. Let's see. I mean, I don't see why not.

I think they're still using at the very least I think they're doing this underwater. They're semi aquatic and found in low elevation areas. So yeah. They're living there under under water lives. Yeah. I mean, that makes sense. And so, they blow the bubble, but they don't let it escape and float up. They suck it back in.

They probably do that a bunch of times. And then, whatever is in the water is evaporating into the bubble. Yeah. They can detect that. Yep. Which is so cool. I think it's so weird. That is so cool. I guess, if you want to smell the water, that's what you have to do. You have to go.

Like really little ones. Yeah. Or like if you're a shark, apparently they have these nasal cavities. I think they're called nairs. And so one side of the nair is for pulling water in and the others for letting the water go out. And so like along the passage, it passes the sensory cells, cells, and that's how like it smells and processes the water. How are we distinguishing that from taste? Because if I like put some like Coca-Cola in my mouth and swish it around and spat it out, but I have to have it come in one side and then it's spit out at the other side, I'd basically be smelling like a shark. True. I don't know. I'd basically be smelling like a shark. True. I don't know.

Is there like grain parts that are different, Lee involved? Maybe. That's my assumption. It also might just be physiology, where it's like, well, is it using the nose holes? Yeah, that might basically be what it is, because this is like, so part of the mystery is also,

and why we were talking about blindfolding dolphins, is there's this idea that cetaceans, cetaceans, whales and dolphins, they can't smell, but in 2008, there was some kind of dissection of a whale that revealed some sort of olfactory bulb, so maybe they do. And so, there's the question of how do we find out? Like how do we even know?

Are they smelling things? Can, like if we wanna test out, what, sorry, do you say what kind of way it was? No, I did not, let me see. It doesn't really matter because no matter what, it's gonna be really hard to tape its eyes shut and it's mouthy shut. Yeah.

And be like, you can only smell. Yeah. I think it was a bowhead. It was part of a bowhead hunt. That's good. Yeah. Yeah. So I don't think they're going to be

like real. They're known as their blowhole. Yeah. So I feel like they're not breathing in through their blowhole. Yeah. At that point, it's just tasting. So what apparently it was, is they're not smelling underwater.

So maybe it's just when they're coming up in the air. Oh, okay. So maybe that's like the different, so they can smell, but maybe it's not, that's the trick is it's not underwater. We were, and we also found a study where they took dolphins and like put a stinky fish bucket and a not stinky fish bucket and like measured how much they sniffed the stinky fish bucket. But that was also out of the water. So they are using their blow holes to smell with.

Right, but not underwater. Yeah, so I have this idea of imagining a dolphin, like a dog, where it's just like, got its nose down in the ground, it's like, except it's on the top of the head. It's just trying to sniff us, think you fish bucket. Yeah, it's looking, it's trying to find. Find out where that smell is coming from.

But yeah, I think that's the way we test out how they're able to smell. But like you said, like we don't know, are they tasting the water? Are they smelling it? Like what's going on? I don't know. Well, it does water? Are they smelling it? Like what's going on? I don't know. Well, it does make me kind of feel like I just have one very bad nose and it's my mouth

and one very good nose and it's my nose. Yeah. It's like the mouth. But what would you rather do without? Like if one had to be blind to what it's doing? Oh, okay. I was like, I need my mouth. Yeah. Can't just take away my mouth. I like, I need my mouth. Yeah.

I can't just take away my mouth. Right, right. Yeah. Like, the nose is basically a backup. Fair. Yeah. Oh, I think that I'd rather lose my... What?

I don't know. I guess that's where it gets confusing because you're like, if I lose the sense of taste in my mouth, do I still have a sense of taste through my nose? Yeah. Or like, but you wouldn't get that like, that like big, good, strong taste thing, which is the overwhelming salt, sweet, bitter sour, umami, yeah, thing, which is very,

bodies are confusing. They're so complicated. I'd have to think about it a lot if there was some kind of, you know, all-powerful alien who wanted to just make up my day bad. Yeah. It's gonna be like, I'm gonna take away one. I'm like, why? I don't know.

I'm the alien that does the hypotheticals. Yeah. Made me this way. The alien that does the hypotheticals. That's the job title. But flatworms, do they have just like an organ that detects chemicals in the water? I think so. I think that's the way they work. Yeah. So they're just processing

the chemicals. Yeah. And so like maybe like the person's asking like, do they become nose flying to the salt part? I assume so. I assume at some point to probably, like if you're living in the ocean, your brain doesn't like process the salt as part of that. But yeah. Yeah, I think that there's evolutionary advantage to not thinking that the normal baseline environment has a smell or is even detectable. Yeah. You only get deviations from the baseline. Different organisms, especially if you're talking about organisms that like living in salt water, do they need an optimal salinity? like especially if you're talking about like organisms that like living in saltwater, like

Do they need an optimal salinity? Yeah, some kind of kind of adjustment there. Yeah Well, like there's probably some some like if you are a saltwater fish and you're entering an estuary You'd be like ah this does not taste But have you ever been swimming in the ocean and then drank fresh water? Probably. So this is the thing that I've noticed as a Florida boy, when we used to go to the beach, we'd be like at the beach all day.

And then you go to the little shower at the side of the beach to get all the sand off of you. And when the water would go in your mouth from the shower, it would taste sweet because you had to had so much salt water in your mouth all day. Oh, yeah. Additionally, I'm wondering if like what is the daily like dose of sodium if you spend all day in the ocean?

Like people worry a lot about like I don't want to have too much salt. Yeah. Like people worry a lot about like I don't want to have too much salt. Yeah, it's like I can't have an extra bag of potato chips or those fries. Or get the low sodium tostitos. Yeah. But you got to eat a lot of salt when you're at the ocean. Do whales have part problems because of the salt? Do they need the low sodium ocean? I think the whales haven't figured out. I think they have all

their way out of that problem, but not us. I'd like to know what I, yeah, how much, I feel like somebody has to have done a study to see how much like on average a surfer consumes of sodium and one surf session. Yeah. Maybe it's not that much. It's not like you drink it. Yeah. Maybe it's not that much. It's not like you drink it. Yeah. All right, this next question comes from Jenna, who asks, dear Hank and Deboki,

after watching Hank's recent video about back pain, I have a question. Did bypedal dinosaurs ever get back pain? Packy cephalosaurus and protachiaptorix, Jenna. I feel like I did great on that second one. It was perfect. Did dinosaurs ever get back pain. I know that we can sometimes see evidence of different

disease in cells. So I would be surprised if we had no, no, like there was no dinosaur we ever found that had some evidence of like arthritis in its back. Yeah, so there is not a bipedal dinosaur, but there was a dinosaur called a phytosaur, which apparently is crocodile shaped where they found... Oh crocodile shaped, but not a crocodile, because crocodiles. No.

Okay. No. And so they found spondaloarthritis. So that's like bone mass growing between the joints. So like that probably hurt. Yeah. But otherwise like the main thing that like maybe they could have back pain is that researchers were looking at Tyrannosaurus and they found that they had an inner vertebral discs.

Which is like us. Yeah, like us. So that's like not like reptiles. Reptiles are more like the ball and socket joints like our hip joint. So this was like kind of a surprise, but does that mean that they hurt their back? Does it mean that they had a herniated disc? We don't know. We don't know what that would look like for the T-Rex. Or maybe we do, but we haven't seen it yet. Here's, I mean, there were a lot of T-Rexes over a long period of time. There was no T-Rex that didn't get a herniated disc. Some T-Rex at some point add back pain. It was definitely not as common as it is in people,

because we are terrible at having backs. But it doesn't make me wonder about like, you know, a patisaurus, or like the big, the big long neck boys. It seems like a lot. Yeah, it does. It seems like a lot to work. And like, like if you wake up with a bad neck one day,

but that is your entire motor survival, what do you do? I think I'm with a bad neck, but you're a dinosaur that's almost all neck. Yeah. Okay. Like do giraffes get like little cricks in their neck? I mean giraffes like neck fight, which is wild.

Ah. They're so painful. They whack each other with their horns on their necks. Yeah. Uh, I don't know, man. It seems like if you can get up to that level of nonsense, they're probably pretty sturdy. Yeah. But, but again, but we got to this level of nonsense and I will start. Yeah, we

We get up to so much nonsense. Yeah Yeah, I bet I can't would dinosaurs think we are like would they look at us and be like do you like how do you guys function? right like? Yeah, I mean there's there is no doubt in my mind that every single conscious organism would find any other species of conscious organism just so entirely, perfectly, absolutely bizarre. Yeah. Like, in no way, you're like that.

Yeah. How do you live like that? Are you serious? You put your wet face hole on the other person's wet face hole, and that's like great. Yeah. It's like one of your favorite things about life. No.

I mean, I spent the weekend watching dogs sniff each other's butts. Yeah. That's all I have to offer. It's like, we don't do that. That's probably extremely normal to like that behavior to us is way more normal than whatever we do to Ali yes, yeah, yeah, but no, I can't really see I can't really see being a species that sniffs butts for a living. No, I'm gonna probably skip that. Yeah, but I think back pain is probably just a way of life for a lot of the animals.

I mean, one thing I definitely know is that everybody's got pain. There's kind of not a nice way to go out. Yeah. Naturally. So everybody's got pain, especially at the end. Yeah. Yeah, I don't have a joke to add.

Yeah, I don't probably would. I'm not putting a joke on the end of that one. Did we know much about like dinosaur injuries more broadly? Yeah, so I did find a paper that was very fun to look at. They were just like, what do these fossils tell us about how dinosaurs have gotten hurt? They documented percentages of things that were injured, like 25% of injuries were to the upper limbs and shoulder girdle. And I just really like the idea of this like table existing that's just like and I just really like the idea of this like table existing. That's just like, like school nurse for dark dinosaur.

So, these are the injuries they got. Yeah, so there are stress fractures that they're like, can be caused by repeated sudden forceful movements, such as leaping to escape attack or grappling with powerful prey. And like, I just imagine that's like what most of their life is. So yeah, I think that just be hard. I'm glad I'm not a dinosaur.

Any kind, I bet it would be bad to be every kind of dinosaur. Okay, next question is from Luke who asks, Steerhank and Deboki, is my perception of time related to my heart rate, moderately warm Luke. What a problem. I don't know if you're asking this because I just, of this study, but I just saw a study published about this.

Like, yeah, like a week or two ago. Yeah, I remember seeing this too and like immediately thinking of it when I saw this question. Because basically researchers at Cornell, they hooked up some undergrads to electrocardiograms to measure the length of their heartbeat, and then also had a tone setup that would... So it was a computer hooked up to the electrocardiogram as well that would play a tone when I think when they're the heartbeat or something. And so basically, okay, sorry. So researchers of the Cornell, they hooked up undergrad to electrocardiograms to measure the length of their heartbeats,

and they also asked them to estimate the length of these audio tones. And so there was like a correlation between a lower heart rate was connected to a, I think, a longer sense of time. It was kind of confusing to understand like how, whether like it was like the length of the heartbeat or like the heart rate, I was trying to read a few different things and each article and press release said kind of phrase it differently. But my understanding is that basically yes, your heartbeat is related to the way that you estimate time and you understand time.

That's weird. And this is all, there's been a lot of sort of having and a hawing about the perception of time, especially in high stress situations that it seems like time slows down, and then there's a, you know, like when you're time flies, when you're having fun, that's definitely true. And time goes very slow when you're very bored. That's quite easy to measure.

I love laboratory studies about boredom, because people sometimes say that they don't, they don't get bored. I never get bored, but scientists can induce boredom so easily. They have procedures for it. Yeah. They've got like, they're like games that they're like, you have to play this game

and the game is just so bad. It's like a computer game and you have to just do the same thing forever and it's like people people are like I hate this a lot and it is takes it is not and I like I don't know there's something else to it. I don't remember exactly but I just love the idea that they're like known protocols for inducing boredom. That like boredom scientists use the same technique every time so that they can have like comparable research. Yeah. Like standard boredom induction. I hope that they messed up the first few times and it was like this game is still too exciting. Yeah, they're having fun. I'll do this.

Yeah. I mean, I've played some games that are just me doing the same thing over and over again forever. And I like, for some reason, my brain's like, yeah, that seems different. Yeah. Every time I play the game of life, I do the exact same thing.

I like, we'll go for the same cards. I haven't even played it in a long time, and I know exactly what I think. I've been what I thought you meant just like waking up in the morning and doing your day. Yeah. I pick out the same cards every morning from my next day. These are my day cards today. Maybe I should have a bunch of cards on my nightstand to be like just pick out which one I'm gonna do today. You like today? Yeah, you must call a friend. Yeah.

You must walk outside for your stupid mental health. Today, you must eat a corn dog. And it's like, I'm like, I think cards. Yeah, I think that's what astrology is. I think you would just wake up and you let the horoscope tell you. Tell me what you want to do today. Tell me what you have to do today. It's like be very careful going on the stairs.

I'm like, all right, card. I will. Yeah. That's probably for every day. I should always be careful going on the stairs. I'm 42 years old and I got bad ankles. That's what you need the cards for. Like today's a bad ankle day.

Yeah, please tell me. Do we answer this question? I think so. I think yes. Your perception of time is related to your heart rate. My perception of how is dependent on who wrote the article I'm reading. 45 participants monitored with. Oh, sorry. You think she.

Hello, I looked at a cardiogram, but the bookie wrote in. Oh, sorry. I looked at cardio gram, but the bookie wrote in the notes egg. EGG. But imagine if it wasn't egg. How did eggs get involved? This is a separate study where they had to do something with an egg. Maybe it's like an egg typer. Sorry, that I like, and then egg was connected. Like in the next line, the same typo, I think it's like an egg-tiver? Sorry, and then egg was connected.

Like in the next slide, the same typo. I think it's auto-correct. Egg is connected to a computer. I think it could get auto-corrected. Yeah. Man, this is a great experiment. All right, another question is from Ray. Who asks, dear Hanger DeBoki,

when I'm sick and my mom tells me to go for a walk and get some fresh air, does this do anything? Or is it just a saying that comes from when we knew a lot less about illness? I know that John has mentioned TB spreading out to the American West when doctors sent people there for fresh air, but that obviously didn't cure it. Is there some real science to fresh air as a cure? Not just something you say, Ray, I'm going to venture a guess. That can't hurt. Yeah, I think that's sort of the, the, just of what I got. I think at the very least, ventilation is good for you a lot of the time. Yeah.

Like I think we saw that with COVID, we're like having air flow. It's just generally a good thing. So I think that's a big part of what fresh air does for us, especially if a lot of us, like I spend all day at my desk and I feel like when I go outside, after a long day at the desk, I'm like, oh, I feel like I can breathe again. Yeah. Yeah, there's like a wild amount of science

about this actually like like building ventilation and like the fluid dynamics of air moving throughout a building is kind of a really big deal and it is a part of how engineers, Shini Samara who did the Crash Course Engineering series studied like air movement in buildings which in her engineering degree. And I was like, and there can be areas where air, like the ventilation kind of doesn't reach it. And so it gets very stagnant and can have a build up of carbon dioxide from people, but also like VOCs from Carpet or Painter and other off-gastings. And so like it's like less healthy air you've got to like hit all the cracks with your ventilation strategy wild.

Yeah, so carbon dioxide is a big one and it is just good to get out of a house and into like the normal, like your house will always have an elevated level of carbon dioxide because it's got people in it and yeah it's you know sealed from the outside yeah it's a big thing to need for you to build up so and like that does just kind of make you feel better but also it just feels better to get up and walk around even if you feel like just feels better to get up and walk around, even if you feel like just do like one lap, well, lap around the block.

Yeah. Yeah. It's annoying. I find it very irritating that it works, but it's like, okay, I guess it works, it works. Yeah, when I had COVID, I did not leave the, like I got COVID and I was in a hotel room and I had to stay in that hotel room for like 10 days

and I didn't leave the hotel room for that whole time. Oh man. Very bad. Yeah. That sounds very difficult. That's not the life you wanna live. But Dordash exists, so I had everything that Taco Bell has to offer.

Did you have a favorite thing from that? Like what was the best thing you got from Taco Bell and that time? Oh tell me what, Taco Bell, DoorDash, anything crunchy is a no-go, because it's gonna not be crunchy anymore. So that was a bit of a disappointment. But honestly, my favorites remain my favorites, you know? I just like the chicken taco. I like the bean burrito, which is gross. That's all good. Yeah, I'm like, I love this.

When I was in high school, I was very mad when they raised the price of the bean burrito to 39 cents. So that's how old I am. Now I'm trying to remember how much the bean burrito was when I was younger. But I can also imagine being upset about that. That's not what you didn't go to Taco Bell for price rates. Yeah, yeah. This is supposed to be a 29 cent burrito.

And that's a normal thing to expect from the world. Oh, terrible. Which reminds me that this podcast is brought to you by the 29 cent bean burrito only available in the mid 90s. It's a co-valent Orlando Florida. This podcast is also brought to you by egg, the source of all of your best experiments. Just egg. Just hook it up. Hook it up to your computer right now. Podcasts also brought to you by Dolphin Blindfolds available on Amazon.com so you can do all of the different research that you need to do on your

friendly neighborhood citation. This podcast is also brought to you by the alien that does the hypotheticals like Dolphin Blindfolds. He's so bad, I hate him. Oh, God. Hypothetically, if you were stuck in a room for 10 days and you had to do a dash from one place, why did you pick Taco Bell? I wanted to be sad, you know?

Yeah, no, I understand. I think Taco Bell is a very good comfort food, especially in COVID times. Oh, Lord. This next sciencey question from our sciencey dear egg and John archives is from Leo who asks dear egg and John, I'm wondering if orange peels are airtight. I saw an orange in my dad's car while I was riding to school and I thought, while I was writing to school and I thought, you just said, yeah, no, okay. That's a very funny story to me.

To tell me right after you asked the question, yes, you were thinking, is it airtight around the orange? I've been listening to the pod for about a year. Aries, not a Leo from Leo. Our orange peels airtight, well, is anything. Yeah. Yeah. So.

Important. What is airtight? What is airtight? Yeah. Because there's some things in the air. There's a few things in the air that are much smaller than most of the things in the air. Those things will be less airtight to those things than the other components of the

air. Yeah. So I think I've decided that they're not airtight. I spent a few different ways thinking about this. I was like, well, to start off with, I think you can wash an orange. So it's watertight, probably, right? Like, I don't think the orange gets wet unless I'm wrong, but like, I think you're fine. I think you're right. I think you're right. I, there's only one way to find out. Everyone will wash your oranges right now.

But it just dunk your oranges in water. And then, so no, here's what you have to do. You weigh your orange was a very precise scale, put it in water, let it stay there for like two to, no, that's not gonna work. Yeah, cuz then you let it like, like there's gonna be all kinds of different mass that's happening. And then so the other thing I was wondering about

is like whether or not ethylene gas is like a part of orange ripening because I was like, okay, so ethylene is the gas that isn't involved in fruits ripening. If it gets past the peel, then we know that it's at least permeable to that gas. But apparently citrus fruits aren't like super like, like they don't really rely as much on ethylene, I think, for their ripening. Though people do use ethylene to make the color of the peels more even. So maybe there's that.

But then finally, I found this paper from 1992 that was comparing the gas permeability of fruits with wax coating. And they were looking at the permeants of them. So that's the actual variable they're looking at. And it turns out that an uncoated, non-refrigerated orange does have like a non-zero permeability. It's 100,000 something like whatever the units are milliliters per meter squared times day times atmospheric pressure I think or something.

Oh, okay. So there is, and then that permeability does go down with a wax coating. So basically in some way, I think there is something permeating the peel. And so they didn't specify kind of what things would be permeating, but I don't think it's airtight. I think it's air.

If it's air pressure, it's probably the atmosphere. Right. Do you remember the actual number? I think it's 100,000. 100,000. Yeah, which is a very... 100,000 milliliters? 100,000 milliliters per meter squared per day.

That's a lot. Yeah, but that's a big meter squared. That is a lot of orange. For sure. A meter squared is a lot of orange peel. It occurs to me that you can determine if an orange peel is watertight in a very simple way, dboki, and I have ashamed, that I did not think of making it into a little cup

and then drinking out of it. It's obviously watertight. You can make a little cup out of orange peel and it's not going to like dribble out the bottom. Right. But in the same way, I feel like if I put a orange peel up to my mouth and tried to blow through it, I would not be able to. You wouldn't know what's coming out the other side, probably. But something would be, some very small amount of gas probably would be. Yeah, I think it's not going to be completely airtight. And if I did that too, if I had, if my mouth was the one, like, can you use an orange

peel as a mask? Can you breathe through it, either, or would you be completely suffocated? Yes. You could definitely be suffocated by an orange peel. I'm confident. And I'm going to, that's not what I meant. I want to do the thing where you put the orange peel in your mouth.

And she smiles and it's just orange. And then blow really hard and see if I can breathe through. And I bet you I will not be able to. But if I had, my, if my mouth was one meter square and I had a one meter square orange peel and I put my one meter square mouth on that one meter square orange peel and I, and I breathed, I could breathe in 100,000

milliliters of air over the course of a full day. I think so. Which would not be enough to survive. Yeah. I'm sure that I breathe in way more than 100,000 milliliters of air infold day. I think so. Which would not be enough to survive. Yeah. I'm sure that I breathe in way more than 100,000 millimeters of air in a day. Yeah. I hope so.

I don't know how much, but I think it's more than that. I think it's more than 100 liters of air. Yeah. So this was not the point of the question, but yes, don't breathe through orange peels. But like, yeah, we can give terrible life advice even when it's just science questions. But what it really comes down to is it would probably seem airtight to us. I think so.

You could fill an orange peel up with air and it would feel like it was like squishy and like a balloon. Yeah. But then I think so. Depresurized fairly quickly. Yeah. Just like how balloons aren't actually airtight because they empty out eventually. What is like, do we know like what the most airtight thing is? What's, I mean, it's got to be just like an airtight thing, but thicker. Yeah. The space station. Yeah. Metal like a thick sheet of steel, probably pretty airtight, acrylic plastics are

probably pretty dang airtight. Yeah. It's probably really to do with the thickness. Like that's probably why balloons don't feel very airtight because they're very thin. Stainless steel is the most durable material for airtight food containers. Like cans. Yeah. Cans are pretty dang airtight.

So just wrap your orange up in a can. Bite it into an orange and it just steal. Yeah. Yeah. Yeah. Leo, I feel like we really helped you in this situation. Of, where, the first thing we need you to know is that none of the words mean anything.

Airtight is just something that's made up in your head. There's, there is so small it can get through anything tiny. Even an orange peel. I wonder how much air leaks out of the International Space Station every year. Right. A point six pounds of air per day. Wow. By August 2020, the problem had increased fivefold.

Oh, so there's actually a leak. There's a leak. They used astronauts plug leak on the International Space Station with the help of floating tea leaves. Everybody be very still. I'm gonna waste some tea. Don't make any turn off all the fans. I they look but they probably had to turn off all the fans. Yeah. The tea leaves started going. I love that. I want to watch the little mini series of it. Yeah, there's several photos and videos of the direction

of the T-bags flight or word intended to fly. And this precisely shows the direction the air is blowing from the possible air leak. So yeah, they used the T to figure out where it was, and then they taped it. As you would actually use the tape. They didn't use the TV to tape it. Yeah.

And then they just, they like got their spit on the leaves and just push it in there. Yeah. I bet though that the the space station would, even if it were perfectly airtight, still lose some air. So by which I would mean not perfectly airtight. But that'll be a very good way to test because there's a big pressure differential. Yeah, in those two situations. Sure is. Though there's big pressure, bigger pressure differentials right here on earth, sometimes like in the boiler of a power plant, way bigger than that.

All right, this next question comes from Vivian who asks if you're angan tabochi. Some friends and I were talking to my their friends mentioned how horrible ants smell. They said that ants smell like rotten cherry chocolate. I have never smelled it in it, voluntarily or otherwise. Why can some people smell ants? And why do I not smell anything, a very important ant question, Vivian?

Deboki to ant smell. Yeah, yeah, apparently. This is like my favorite kind of deer hankin' John question because I saw it and I was like, that's not a thing. And then I looked it up and it's like, that's a thing. Like apparently ant smell like formic acid.

And I don't know what formic acid smells like. I don't know if you do. No, it's just a thing. But apparently, something that only some people can smell. Uh, what? Yeah. So to some people, apparently, it smells like blue cheese, other people, it smells like citronella.

It's probably just a genetics thing, whether or not you're one of those lucky, I guess people who can smell it. But yeah, that is the ants smell. That's the ants smell. I mean, I've been around ants plenty. I've been, formic acid is the stuff that fire ants put in you that burns and makes you itchy.

And so I've, trust me, I've had it in me before, but I've never smelled it. That's so weird. Yeah, so I was so curious like for everyone who smells ants, like how many ants does it take for you to smell? Like, if you, if there's just one ant around, are you like there's an ant, or how many ants do there have to be for you to realize this? It's apparently also smells like vinegar, which makes sense with blue cheese.

And it's only smellable by some people. Wow. I love that. And I also love the idea of just feeling and totally being gassed lit by your friends. Where they're just like, oh, it smells so bad. Like what are we gonna do to Vivi?

What are we gonna say? You're not gonna trick me. Yeah, I would totally not believe someone if they told me that ants smell so I Apologies to all of the hypothetical people. I didn't believe because apparently according to the internet you're you're all right and ants smell Oh lord All right, that was an easy one and this question comes from Noah whoola, who asks, dear Hank and Deboki, why can't humans drink river water anymore?

Like chimpanzees, they got no problem drinking from natural bodies of water, so at what point in our evolution did we lose this ability to deal with whatever bad stuff is in the water? Do other animals have this problem, or is it just us? Not the city, Nola. I'm gonna venture a guess. Well, I think there's a bunch of stuff going on here, but water-borne pathogens are not just a problem for people. No, there are problem for everyone.

Yeah. I think that there are reasons why it can be worse for people and particularly because we tend to live in really high densities of people. And so we can kind of, there could be up to start, like, there's more human pathogens going into the water source. And so you're more likely to get it. But yeah, I mean, animals get, and there's all kinds of stuff that we're dealing with here. So like, there's chemical things that you don't want to eat that might be in water. That's probably the thing that if you're just talking about river water, it's not that much of a concern, unless you're near like a old mine

or something. And then there are bacteria and there are parasites and there are viruses and there are like single cell parasites and you know, like eggs of bad things. So yeah, there's all kinds of different things they can live in water and make use of your body. And those are the things to be worried about. And that is a thing that happens for lots of animals. Yeah. And so, I think, sort of a parallel, maybe,

to what you were saying in terms of human density. For animals, I think the parallel to that is watering holes. So it's not quite river, but a lot of animals, you know, they go to a shared kind of watering spot. And so that does actually lead to diseases spreading between the different animals that are gathering there. But one of the things for animals is that they're going to these rivers and these waters over the course

of their whole lives. And so over the course of their lifetime, they're probably exposed to a lot of microbes at a low level, so that gives them exposure. So that might help actually build up some of their immunity. exposed to a lot of microbes at a low level, so that gives them exposure. So that might help actually build up some of their immunity. So I feel like that's sort of reminds me for me, like I used to go to India every summer

and like my family, like they grew up in India so they can drink the water in India. I cannot drink the water in India without having problems. So like I don't know if this is like sort of the similar kind of mechanism. I assume it's kind of the same thing where it's like, you're exposed to that water over a lifetime where you've built up that immunity,

which is why you shouldn't try to just go do that now. Like if you've grown up not drinking that water, you shouldn't be like, I'm gonna get that fancy immunity now. But if you've grown up with it, you might have that low-lying exposure. And yet at the same time, you're still at a higher risk for a lot of the other things that are in the water just because it might have other stuff going on that you can't build that immunity

to. Right. Yeah, everybody is at risk, but some people are at more risk. This is such an interesting topic, the sort of, like there's a sort of meme that if you'd never brushed your teeth, you wouldn't have to brush your teeth. This is not true, but there is truth in it.

So if you never brushed your teeth, you might have like sort of a more broadly successful and competitive microbiome in your mouth where there isn't like one species of bacteria that sort of do in a lot of damage. But you are going to have more problems if you don't brush your teeth than if you do, but you may have even more problems if you start out brushing your teeth and then stop. And so people, like we get a question all the time, like, what did people do before like dental hygiene? And the, you know, the simple answer is they had huge dental problems.

But the complicated answer is they maybe had fewer dental problems than if you brushed your teeth and then stopped and then didn't ever brush your teeth again. And this is exactly what happened with polio, which was a disease that was around and was not really sort of at epidemic levels because people were exposed early on in their lives. And then when we sort of got hygiene, it became, you would be exposed to polio later on in your life, and then it became a bigger problem because it, you know, because of the particular pathology of polio. Right.

And so like, you can say to that, well, we shouldn't have done hygiene, but no, and, you no, and the remarkable thing is then we've created a new problem for ourselves and then we solve that problem for ourselves with the polio vaccine. So it's just one big long story of trying to be a person. Yeah.

And also. You take care of one thing and then something else just comes up. Yeah. But like hygiene overall is good, even if it led to an increase in polio that we then had to conquer in another way. Yep. All right.

Well, why don't you do Mars News and I'll try to find something about AFC Wimbledon. We'll pull up the Mars News. I really liked this Mars News. It actually has a little bit of the feel of, yeah, fixing the International Space Station with tea leaves, but just a little different. So this week in Mars News, NASA scientists and Lockheed Martin Space Engineers,

they solved the mystery of the missing Mars orbital fuel. So the Odyssey Rover was built by Lockheed Martin and was launched in 2001, and it doesn't have a fuel gauge. So when scientists are tracking it, they have to rely on math and various tests to figure out how much hydrazine propellant is still left from the original 500 pounds that was sent up with the orbiter.

So they do this by heating up two propellant tanks to see how long it takes for them to reach a set temperature and the emptier the tank, the faster it reaches that set temperature. But recent tests in 2021 and 2022 suggested that the orbiter had less propellant than expected and that it would be running out in less than a year, which is kind of worrisome. So the scientists from JPL and Lockheed State Martin Space worked together with a spacecraft for pellet estimation consultant named Boris Yenler. You suggested. I just really like that job.

That's great. There's one. They had a huge, a bunch of people applied for that job. Yeah. He's got the phone like on ready. there's one. They had they had they had a huge a bunch of people applied for that job. Yeah, he's got the phone like I'm ready. It's like this is my time. So anybody, anybody need any space propellant estimation because it's all I know how to do. Yeah. So Yenler suggested that the problem might be coming from some other source on the Odyssey, which might be adding heat to the fuel, which is causing the temperature to rise too fast during all of those fuel tank heating tests.

So when they look further, the scientists found that they're actually heaters on the fuel line that were warming up the propellant takes, and those were messing up the results of the test. So taking into those account, so taking those heaters into account, they were able to estimate that the Odyssey has nine pounds of hydrazine left, which could allow it to operate for at least a few more years. That's great. Did we, should they have put a fuel gauge on it? I don't know.

I don't know how, I don't know if the orbiters now have a fuel gauge. I don't know how you measure it. You can't do it by weight. Yeah. I can't like weigh it. There's no, There's no gravity. Yeah, I don't know if you're just like, well, we've got math.

Math will help us. It'll do it. Well, just if all worse comes to worse, we'll come for it. Yeah. And like, clearly they knew because they set up the infrastructure to run these tests to be able to gauge how much fuel there is.

But yeah. That's very interesting. Yeah. Yeah. Well, in news from AFC Wimbledon, run these tests to be able to gauge how much fuel there is, but yeah. Yeah. Yeah. Well, in news from AFC Wimbledon, here's what I can tell you. Apparently, we need to win some games before the end of the season so that we can still be in league two and not boots. AFC Wimbledon is now at 16th place,

and I have great news. They won a game. See what usually happens with AFC Wimbledon is that they score one goal, and there's one to zero, and then the other team scores two goals. And that did happen a couple of games, or just one game back. That was the most recent one.

But then we did a remarkable thing, where AFC Wimbledon went up, won NIL, and then we did a remarkable thing where A. Siwimble didn't went up one nil. And then they went up to nil. And then the game ended. Oh, wow. Yeah. Did they they just call the game to an end? They're like, we're up.

And that's how it works. Right. Then the clock continued to take until the game ended, uh, which is the thing that you want to have happened, but they did it. They did it. Go from one mill down, one mill up to two, two one down again, which I don't know if you've been listening to Bokey, but A. F. Summeldon has now done that more than any other team. More than any other.

The history of English soccer or some stuff like that. That's wild. I'm glad that they found a way to not do that. No, they got to just do it again. And it was also, it was a team that's higher than them in the rankings. That's what I always look at when they like playing a game. Yeah. I like make sure.

Because if it's like the last place team, I'm like, well, they were gonna win that game. Yeah. Yeah. It was, you know, it a team that that's high high high. So where is AFC Wimbledon in the rankings? They're 16th of 24. Okay. And there's like points that they get. Yeah.

And AFC Wimbledon has 46 points. And to be, if they were to be in the bottom, they would need to have 36 points. Okay. So there are 10 points out of relegation right now, which is good. That's good. But they do have to keep winning some games. So it's good that we won a game against Walsall. Walsall.

Yeah. That's a great name. Oh, they're all great. Yeah. The next two down. So between AFC Wimbledon and Walsall are Tran Mir, which is just like it's exactly the same thing as Walsall for some reason. Tran Mir and Walsall are the same. They just...

Like, they feel the same or they feel the same. They feel the same. Because they have the same number of points. They do have the same number of points, but my brain, Tran Mir and Walsall, as anyone seen them in the same room. And then the next one just about very swindled in his Grimsby town. That's great.

That's amazing. I love it. All right, Devoki, thank you for making a podcast with me. While John continues to recover and also I think is doing some fun things. If you want to send us your questions, you can do that at www.hinkinjohn.gmail.com. We don't have a podcast without your questions. Thank you very much to your science questions in particular. Those are always very fun for me and Devoki to work on.

This podcast is edited by Joseph Tune of Medicets. It's produced by Rosie Anna Halls-Rohas. Our communication coordinator is Brooke Shotwell, our editorial assistant. As always, is Debuki Chakravarti. The music you're hearing now at the beginning of the podcast is by the great Gunnarola, and as they say in our hometown. Don't forget to be awesome.