SciShow Tangents - SciShow Tangents Enhanced Classics - Experiments in Space

Episode Date: January 5, 2021

SciShow Tangents is still on a break, but we have another Enhanced Classics for you! This week, a rerun of Experiments in Space with a brand new Ask the Science Couch and Butt Fact!Follow us on Twitter @SciShowTangents, where we’ll tweet out topics for upcoming episodes and you can ask the science couch questions! While you're at it, check out the Tangents crew on Twitter: Stefan: @itsmestefanchin Ceri: @ceriley Sam: @slamschultz Hank: @hankgreenIf you want to learn more about any of our main topics, check out these links:[Truth or Fail]Chicken Fathttps://www.nasa.gov/topics/aeronautics/features/aafex_biofuels.htmlBone losshttps://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=187Perfumehttps://www.nasa.gov/audience/forstudents/9-12/features/spacescents_feature.htmlhttps://spinoff.nasa.gov/spinoff2002/ch_1.html[Fact Off]Wake Shield Facilityhttps://ntrs.nasa.gov/search.jsp?R=19920014405https://er.jsc.nasa.gov/seh/pg46s95.htmlhttps://uwaterloo.ca/molecular-beam-epitaxy/about/what-epitaxyhttps://science.nasa.gov/science-news/science-at-nasa/2002/03jan_bioniceyeshttps://www.sciencedirect.com/science/article/abs/pii/S0042207X01003839https://www.sciencedirect.com/science/article/abs/pii/S009457650000148XImage: https://archive.org/details/STS069-724-095 Mouse sperm experimenthttps://www.pnas.org/content/114/23/5988http://iss.jaxa.jp/en/kiboexp/theme/second/pmlatter/spacepup/[Ask the Science Couch]Rocket thrusthttps://www.grc.nasa.gov/www/k-12/UEET/StudentSite/engines.htmlhttps://www.sciencelearn.org.nz/resources/390-rockets-and-thrusthttps://www.researchgate.net/publication/228785798_The_merits_of_cold_gas_micropropulsion_in_state-of-the-art_space_missionshttps://www.grc.nasa.gov/www/k-12/rocket/rktth1.html[Butt One More Thing]ISS Toilet

Hello there, listeners! We're taking a little break here at SciShow Tangents until the new year. So, what you're about to hear is an episode from our back catalog, but we're going to mix it up a little bit. See, every week we get a bunch of great listener questions, but we only answer one of those questions because we only have time for one. So in this episode, we've recorded a whole new Ask the Science Couch with a whole new listener question, and on top of that, there's a new, but one more thing, but fact. So you can be sure to listen all the way to the end if you want to hear that. Because of course you do. Hello and welcome to SciShow Tangent, the lightly competitive knowledge showcase starring some of the geniuses that make the YouTube series SciShow happen.

This week, as always, I'm joined by Stefan. Hello. What's your tagline? Fucked up from the neck up. What? Come on. Not. I'm expecting that.

I say it because I'm wearing a, I i mean i think it's fair to say a snazzy shirt yeah but i haven't shaven in days i haven't had a haircut in months i i'm just yeah it's a mess up here yeah we're also joined by sam schultz sam what's your most boomer quality i must have one but i feel like I'm pretty much young at heart. I do like mowing the lawn. Oh yeah, that's pretty boomer. I live on a second floor, so I have some AstroTurf on my back

porch. I do like to go out and sweep it. That's pretty boomer. Yeah, I like that a lot. What's your tagline? Down with homework. And Sari Reilly is also here. What's your tagline? Down with homework. And Sari Riley is also here. What's your tagline? Rumbly tumbly.

Ooh, delicious. And my name is Hank Green, and my tagline is the floppiest flippers. Every week here on SciShow Tangents, we get together to try to one-up, amaze, and delight each other with science facts. We're playing for glory, but we're also keeping score

and awarding Sam bucks from week to week. We do everything we can to stay on topic, but sometimes we go on tangents. And if the rest of the crew deems that tangent unworthy, you will be docked a Sam buck. And I need every Sam buck I can get because I wasn't here for two episodes. You're down in the mud with me. Down in the mud with Sam. Luckily, I get to drag myself out one point at a time, starting with the science poem to discuss our topic of the day. The science poem this week is from me.

Light a fire on the ground, we know what it'll do. Or how a mouse will procreate, or how a human poos. We know the ins and outs of life upon the planet's face. But there's always more to know. Just ask, but what's it like in space? A sphere that spins in gravity spins different in free fall, and facets of microscopy just aren't the same at all. We have to know where fire will go or how a crystal grows and the effect upon the body. Well, there's so much more to know.

It's good that we have orbiting a handy ISS, because when you ask if something's different there, the answer's always yes. Space experiments is our topic of the day. Sari, what's a space experiment? Well, it is any science that you do outside of the Earth's atmosphere. Yeah, I guess. It doesn't have to be in free fall, I suppose. No. If you like shoot something up past the atmosphere

and it's like in low Earth orbit, a satellite would probably be a good experiment. It doesn't even have to be in orbit. Oh. You could just get it up there. And then in free fall and in orbit

mean the exact same thing, basically. Yes. Yeah. I mean, not exactly because you can be in free fall but not in orbit. If you are in free fall

and not in orbit, you will run into the planet. Or you're on a roller coaster. Yeah. Oh, right, right. I guess you don't have to run into a planet. You would have to be caught.

You could be caught by something. You will soon be caught by something. Yeah. Or you will run into the planet. I didn't go in this direction, but I was wondering whether, like,

New Horizons counts as a space experiment. Yeah. What is New Horizons? A probe that we send out to like study other planets and things. I looked up the etymology of space. The first use was maybe Paradise Lost, English poet John Milton's thing, to refer to anything beyond the Earth. Right.

And so it's still kind of a vague word as far as is it the emptiness between planets? Is an experiment on Mars a space experiment? Right. It's still kind of a vague word as far as is it the emptiness between planets? Is an experiment on Mars a space experiment? Right. As long as it's not Earth, is everything space? Yeah. I would like to think that it's everything between planets. If it's a Mars rover, it's a Mars rover. But if it's in space, it's like in the void.

So even if it's orbiting Mars, that's a space experiment. Yes. Okay. I think so. Or is that just a Mars experiment? Yeah. Or is it an Earth experiment? Or, yeah,

it feels kind of Mars-y to me. Well, I mean, here's the difference. When we're doing experiments on the ISS, we're doing them on space. Yeah. Like we're thinking about

what's life like in space with more electromagnetic radiation and you're, you know, you don't have gravity. So that's, that's, that's space. Right. Whereas if you got a probe that's like circling the earth and it's like taking pictures of earth. Yeah. That's just a camera. That's just an earth experiment, but a better angle.

But in space, it's an earth experiment in space. Yeah. From space. It's an Earth experiment in space. From space. We should have called this episode Experiments on Space. But my topic wouldn't fit anymore. Well, yeah. I mean, we're doing experiments on space, but we're also doing experiments on things that are in space. That's mostly what we're doing. It's like, what's this thing like when it's in space? And pretty much all the ISS is doing is experiments in space. Yeah, that's mostly what it does. And being in space. And pretty much all the ISS is doing is experiments in space, right?

Yeah, that's mostly what it does. And, like, being, like, in space. Yes. A lot of what the ISS does is, like, stay up. So just maintenance and keeping everything good, making sure there's plenty of food for the astronauts and air and water and not falling down. I thought you were referring to it as a symbol of our human economy.

That, too. It does also do that. It does also, like, put a bunch of humans together in one place. And it says, we are not from any country, but we are humans, which is not something we get in many ways these days. The area code for the phone number on the ISS is apparently Houston, though. So it's like a little bit American in that respect. Yeah, yeah, yeah. A little bit American in that respect. Yeah, yeah, yeah.

There's the thing where there's some argument over like what Catholic bishop oversees the moon. Oh. Because the idea is that like until you like set up a bishopric or whatever in the new place, the bishop from the place where the journey began is the bishop of the new land. So basically it's the bishop of Orlando is the bishop of the moon. So like if a Catholic person died on the moon, that too would go take care of that? Yeah. If you're raised on the moon

and you need some Catholic administration done, I think mostly it's administrative what the bishops do rather than because the local preacher would. But I guess you don't have one. Right. So maybe you have to go all the way up the chain to the bishop.

Yep. Put him in a rocket. Just put a call to earth. Yeah. Yeah. I mean, doing a confessional over, I guess there's probably a secure line you could get on. Yeah. What are we talking about?

That seems like. A tangent. We went a little bit off. That was definitely me. What are we talking about? That seems like a tangent. We went a little bit off. That was definitely me. How are you feeling about it? I learned something. That was a very fun fact. Yeah.

We're going to move on. It is time for Truth or Fail. One of our panelists has prepared three science facts for education and enjoyment. But only one of those facts is true.

The other ones are big, fat, stinking lies. And we have to guess which one is the true one. And if we get it wrong, then Sam gets a Sam buck because Sam is doing truth or fail. In the grim darkness of the far future, space is full of brands. There's a space flight, advertising, publicity stunts, an outlet wall on the moon.

It will all come to pass in the future. But for now, a few brands have already gotten their foot in the door by funding space experiments. Which of these are a real brand-funded experiment in space? Number one, KFC funded research into using chicken fat as an eco-friendly rocket fuel component. Number two, Nike branded shoes with sensors designed to monitor astronauts' feet while exercising

to help fight bone loss. Okay. Or number three, a study funded by a perfume company to see if flowers smell different in space. KFC. Kentucky Fried Chicken. Is it just KFC? I think officially it's just KFC, but you can call it Kentucky Fried Chicken.

Okay, so just for clarity, for the people at home who may not be aware, in America we have a thing called Kentucky Fried Chicken. Other countries too. It's very popular in China. Oh, never mind then. I just assumed by the Kentucky in it that it would be... I think that's why they called it KFC.

Oh, people are like, I don't want to know about this. Yeah. They don't care where it's from. So there's KFC-sponsored chicken fat rocket fuel. Rocket fuel? Rocket fuel. Nike-sponsored shoes that have sensors in them to help protect against bone density loss. Or a study funded by a perfume company to see if flowers will smell different in space. What perfume company, Sam?

A perfume company. Unspecified. Unspecified perfume company. Okay. Would they smell different? This is the thing. Like, as my poem says, nothing is the same in space. Everything is different.

And I think I have heard something about things smelling different in space. I could see this being a lie, though, if it's an unnamed perfume company of just, like, some perfume company didn't want to see a flower smell different they just like sent up nice smelling things to the space station it's like

oh you're stinky up there here's like nice smells yeah that seems like more of a brand deal than like I want to know

what flowers smell like but you never know maybe they just want to help science happen yeah and I know that Nike has those things that they put in the shoes for a while do you guys remember Nike has those things that they put in the shoes

for a while. Do you guys remember those? They have things that they put in the shoes? They hook up to an app or something. Yeah. Oh.

Yeah. And like go in your shoe and it would be under the sole and it would be basically like a Fitbit but in your shoe and I think that they sort of got replaced

by Fitbits. Oh. I was going to say it sounds better to have the Fitbit in the shoe. But you're not always wearing the shoe

whereas the Fitbit's always on you and it tells you what time it is. That seems very reasonable to me, especially because it's like if we could be the shoe on the mission to Mars, that'd be pretty cool. Oh, heck. I mean, yeah, Nike's definitely got to get that one. You're not going to let Under Armour be the freaking sportswear brand of the Mars mission. It's got to be Nike.

Just do it. Only a little swoosh on the astronaut boot. Swoosh on the boots. I'm feeling perfume. Really? Yeah, I know. Just do it. Swoosh on the astronaut boot. Swoosh on the boots. I'm feeling perfume. Really? Yeah, I know. I think it's wild because it's,

but like, I don't know, I'm not going to rationalize it too much because I don't want to sway you to my side and have you guys get my points

because of my wisdom. We didn't talk about the chicken fat. It's true. It doesn't have to say, it doesn't have to work necessarily. They could just fund it and like slap KFC on the side of Rocket.

I think that's because I'm hungry for lunch and now I want fried chicken, but I'm going to go with that one. Does KFC have Uber Eats? I'm just wondering if we should get an order for everybody because that would sound good. By the time we finish, it'll be here. Yeah, that sounds good. We can't order KFC in the middle of our podcast. This is a minus one tangent. I feel like this is a minus one.

Who gets the minus one tangent for the KFC? Well, Hank for suggesting that we should order and then pulling out his phone. Just saying if it's available. I am also leaning towards the KFC one. It does sound sort of plausible to me only because fats have a lot of calories compared to like protein and carbs. And so I could see them processing it in some way that maybe it could be used as a fuel. We definitely have turned fat into fuel, you know, biodiesel. We can't get KFC, but they got Popeyes. Do you want Popeyes?

I would eat it. I'm hungry. I'm getting some Popeyes for me and Sari. Do you want some, Sam? I mean, if you're getting Popeyes. I'm not going to say no. All right, we ordered Popeyes. What's the answer?

Because it's been 100 years, please remind me what you all picked. I picked KFC fat. KFC fat. And I picked the perfume. The correct answer is the perfume. What? So can I tell you why I thought it was perfume that I didn't tell everybody? Yeah.

Because I don't think that NASA likes it when there's too much closeness between the thing and the brand. So if they were like actually saying like saying does this perfume smell super good? Then I'd be like, no. But if it's like, we just want to know how people smell in space. And then the perfume company can put out a press release that's like, we funded this scent study. Whereas these other ones

seem too close. And NASA wouldn't like it. That was my mistake. Couldn't trick Hank. So in 1998, International Fragrance and Flavors. That's the name of the company. Nice. Boring. I like it.

Yeah, it's kind of old-fashioned, huh? Very 50s name. That's a great conglomerate name, yeah. Yeah, it's a fragrance conglomerate, and they worked with NASA's Commercial Space Product Development Program, which is a whole wing of NASA devoted to that product development in space. They sent a rosebud to the ISS in a plant growth chamber. And when it bloomed, they took samples of its scent compounds

and they reported that the smell had changed from a very green, fresh, rosy smell to a more floral rose aroma. Which is certainly not too different. Yeah, I can definitely know that. That's very different from one another, I'm sure. Rose was in both of them. One was more green, though. They both smelled like rose.

Who smelled it? Just the astronauts? No, the astronauts collected samples, and then they brought it back to the experts who smell for a living. I think or something like that. And then the experts who smell for a living were like, ah, different. Notes of green. They think this happens because in the rose, the compounds were mixing in different ways because it was just in no gravity. So things were just mixing together differently, I guess, or sitting in one part of the flower longer than they would have or less time than they would have.

The fragrance was deemed to be more pleasing than the regular boring old earth rose fragrance. And they started to mass produce. The company started to mass produce and sell the space rose smell. And there's at least one product that uses it that I could find a Japanese perfume called Zin, which is described as floral, woody, and spiritual incense. It smells like the inside of your soul.

Yeah. And you can buy that if you want to smell like a space rose. But they don't even advertise it as space smell. They do not seem to,

no. Okay. You'd think they would, but they don't. The chicken fat thing was not funded by KFC and not a rocket fuel, but in 2011,

NASA tested a jet fuel made of chicken and beef fat to see if it was more environmentally friendly than traditional fuel. And it was by quite a bit. They ran this jet airliner idling, and it produced 90% less black carbon.

When they did the takeoff routine, it produced 60% less black carbon. So that seems cool. I couldn't find where they were getting all this chicken fat. From around. Maybe KFC. Yeah, I mean, probably the place where the chickens get turned into food. Into food, yeah, maybe. KFC did fund some stuff in the 90s about egg development in space.

And the little box that the eggs went up in had a Colonel Sanders picture on it. And then Bone Loss is not funded by any brand, but there's a special pair of pants and shoes that astronauts wear to determine if they are basically getting enough exercise of their legs. So there's different exercise machines they can use up there to try to keep their bone density up because it's a big thing in space that your extremities bone density will go down because you're not using them enough. And so this one experiment was in 2002 through 2006, and it was called the Foot Ground Reaction Forces During Space Flight,

or as NASA shortens it to foot, which is not how those things work. But that's what they call it. And this particular one determined that it was not even close. They were not getting even close to the right amount of exercise. So then they went back to the drawing board

and made up harder exercises for them to do in space. So hard to be an astronaut. It's one thing to exercise and know you're not really doing enough. It's another to have like hundreds of people examining how much you're exercising and then telling you you're not doing enough. Yeah, and that your bones are now bent. Right, soft and spongy.

I think if all I had to do was science and exercise though. That would be okay? That would be okay. I think I would exercise more if I didn't have to deal with like all the other things that come with living on Earth. Laundry. Cooking. I bet they have to do laundry in space though.

No, they like eject it out. They just like don't wash their clothes. They just put it into a pot and send it back down to Earth? I think so. Or like get it destroyed. Incinerate it right there in space? Not in space but like in something that will get destroyed in the atmosphere. Oh. Instead of like getting safely back.

So they just go up with like enough shirts and pants and stuff to last them for as long as they need? I didn't look into this enough, but. That's kind of what I do when I go on trips to Europe. I just take what I need and then buy new stuff as it goes along. Oh, really? Yeah, bring all my old underwear and I buy new nice European underwear. Do you leave the old underwear? Yeah, I mean, I don't leave it for someone to find.

Yeah, I leave it in the trash. Is Hank's really into geocaching with his own underwear? All right, we're going to take a short break and then it'll be time for the Fact Off. Welcome back, everybody. Sambuck totals. Sarah's got nothing. Stefan's got nothing.

I've got one, though I should have two. No. But I wanted Popeye's. Oh, yeah. And Sam's got two as well. All right. Everything is as it should be. Now it's time for the fact-off. Two panelists have brought science facts, presented the others in an attempt to blow our minds.

And we each have a Sam Buck to award the fact that we like the most. And to determine who's going to go first, I'm going to ask you these questions. What year did dogs Belka and Strelka go into space with several of their rodent pals to become the first creatures born on Earth to go into orbit and return back to Earth alive? 1953. 1953.

That's way earlier than I would have thought. 1962. The correct answer is 1960. Well done, Sari. Are they shooting things into space in 1953? Sputnik was 57. Okay. It all happened in the 60s in my head, no matter when it happened.

A lot of it happened. I was a little too early. It moved really fast from the first thing to being on the moon was 12 years. And then we were like, let's never do that again. We're good. So I guess that means that, Sarah, if you want to go first, you can. Or you can make Stefan do it. I will go first because last time I made Stefan go first, he won.

And then I won. made Stefan go first. He won. So you know the thing that happens when you're driving behind a semi truck to save fuel? It's called tailgating or drafting because the truck pushes air particles out of the way to reduce the air resistance of your car as you're driving forward. Scientists in the 90s during a few space shuttle missions wanted to do this experiment in space to see if they could create an ultra vacuum in low Earth orbit that's 1,000 to 10,000 times better than the best vacuum chambers on Earth. So the tool, the device they used to do this is called the Wake Shield Facility, which is basically a four meter in diameter disc that they launched with a robotic arm. They let it go behind the shuttle, and it would hover around 75 kilometers behind the shuttle. And I think

it just followed in the shuttle's wake. It was described as a free-flying platform, and I couldn't find anything to say that it had its own fuel or anything on it. So basically, the shield would fly in the wake of the shuttle, And then in the wake of the shield, it would push away any other like lingering particles that could be in space. And the vacuum, the ultra vacuum was created behind this disc. And it worked. And the reason for all this trouble is they wanted to test creating thin film materials with a process called epitaxy, which is basically depositing really thin layers of a substrate. And so I think on the back of this disc, they had a substrate that they wanted like thin oxidized layers of crystal or something to build up on to research

things like really, really fine semiconductor layers, photo cells, which are sensors that detect light that can be really thin, and even research into bionic eyes because they wanted to grow very, very thin ceramic films to act as replacement retinas because silicon, which is, I don't know, they were trying it out, reacted really badly with eye tissue.

And so then ceramic was seen as more biocompatible. And so they wanted to grow these like ultra, ultra thin films that you could only do in an ultra vacuum. The last news that I heard about the bionic eyes, because that was the coolest part, was in 2002. So I don't know if anyone's still doing it or if it just like because because the films worked like they learned about vacuums here and and this experiment worked two of the three times that they put it into space but as far as i could tell they were just like seeing what could be done in an ultra vacuum right we did it yeah we did it huh when you started that i was like oh they're like gonna launch two rockets and have one follow the others so that it uses less gas get a a little bit better mileage, you know? I don't know.

That seems iffy. Yeah, no. They just wanted to see what happens if you create an ultra vacuum. And then deposit crystalline stuff on a surface very, very, very thin. So we have talked about things that are like one micron thin. Is a micron the smallest thing you can do? Well, there just some things that you can only spread extremely thin in a super vacuum like that? I think it's like it spreads smoother

in an ultra vacuum because in air, there's a bunch of other particles. And even in like a good vacuum, but not a great vacuum, there's the chance of something disrupting like a single layer of atoms being layered on top to form a perfect crystalline structure. And so it like just prevents contamination that there would be any other atom just happening to float around and get incorporated in the crystal structure. Is that like more of a vacuum than space space? Yeah, because there's still some stuff in space is to push whatever stuff might come across the path of this wake shield facility. Push it out of the way to make even more of a vacuum. Right. And it's moving too fast for stuff to like rush in there.

I feel like we should say that in real life on Earth, when you're driving, you shouldn't tailgate trucks to try to get better mileage. That's a super not safe thing to do. Stefan knows. No, I never tailed them that closely because I was aware. Okay. But yes.

Yeah, that's probably a good safety measure. I dabbled in hypermiling for a while. It's also good to not drag yourself behind a space shuttle. So Stefan, can you follow that? We'll see. So there's an experiment that was done by JAXA

and the University of Yamanashi as a first step in figuring out how viable it is to store sperm long-term in space. And so the idea is that in the future, the far future, there'll be like colonies or just like long-term missions, like multi-generation missions perhaps, where we need some kind of assisted reproductive technology in space, both for like humans to maintain genetic diversity, but also for like livestock and things. And also they presented the idea, which I had never thought of, of just like storing genetic material off-world in case of an emergency down here.

Like if something bad happens. Yeah, what? A seed vault. A seed vault. Right, yeah. But like human seed. Human seed vault. On the moon or something. But the problem is that if cosmic radiation

causes a lot of damage to stored sperm, it could affect the future generations that are produced with it. Sure. So they collected sperm from 12 mice, separated them into two sets of vials, and one was sent to the ISS and one was kept on Earth. They called that the ground control sperm.

And in both sets, the sperm were freeze-dried and went through the same temperature changes at the same times for the same durations. And one of the things they pointed out is that in other studies on reproduction in space, the genetic material is not frozen. And so it's actively metabolizing, which means that DNA repair is happening. And so you might not see exactly how much damage is taking place because the cells are actively repairing themselves. But if you're storing

sperm long term, they are going to be frozen. And so after you thaw them out, they have to be able to repair any accumulated damage. And so that's kind of what they're testing here. The freeze-drying part of this is also super weird to me because freeze-drying sperm kills them. But if I understood this whole thing correctly, once you can still rehydrate them and inject them into fresh oocytes, and then the fresh alive cells will repair the DNA of the sperm and then get fertilized. The oocytes will repair the sperm DNA? I think that is what it is saying happens. So they left these vials in a freezer

on the ISS for nine months and then brought them back and did a bunch of testing. And there was no difference in the appearance of the sperm, but the space sperm did have slightly more damage. But when they injected

all the spermies into the oocytes, both groups. Don't say that. Can I continue? You can say spermies. If you say eggies. You can only say spermies if you say eggies.

Otherwise, it's the patriarchy. Yeah. And you lose a hand. When they injected all the spermies into the little eggies, both

groups, the space sperm and the ground control sperm went on to produce little mice pups at basically the same rate.

How long were the spermies up there? Nine months. If we're going to do a seed vault, we need longer than that. That's why I was saying it's kind of a first step experiment because when we do artificial insemination on Earth,

those things have been in storage for over a decade sometimes. And so we need to be able to test very long-term storage. Bury them in the moon. Yeah, if they're buried and shielded, then that would be okay. That was kind of the thing. They were like, yeah, we they're buried and shielded then that would be okay. That was kind of the thing. They were like, yeah, we could make an ice shield or you could stick these in a lava

tube on the moon or something and that would help protect it. But so far based on these results, it seems like it is possible to recover from whatever damage is happening in nine months of being freeze-dried in space. Alright, so do we go with Sari's wake shield facility

to create a super vacuum in space or Stefan's holding on to freeze-dried sperm for nine months in the ISS to see if mouse pups can happen from space sperm? Sam, are you ready to go? I'm ready. Three, two, one. Sary.

Ooh. Interesting. What's the difference? I like Sary's because I like the idea that space is not enough of a vacuum. And we had to be like, let's spend a lot of money to make space extra vacuum-y. I like Stefan's because he said spermies. I was pretending. All right, it's time to ask the science couch where we ask listener questions for our couch of finely honed scientific minds from the future.

We've come to you back now. So Stefan isn't here and we are. We have a grave warning. And we have to, we're going to spice it up a little bit with this new question from at McGoober, who asks, how do rockets work if there is no air to push off of? Great question. This is a great question. It's a great question because I think that it requires the cognitive leap that airplanes require air to push off of, which I think we forget. And that is true that they do?

Yes. Okay. Because the air going past the wing does something, right? Right, but also the propellers or the jet engines are grabbing air and throwing it behind the plane, which is what is making the plane go forward. Planes and rockets

use the same basic physical principle, like Newton's third law of motion, which is when you push against an object, it pushes back with an equal and opposite force. I don't know that that helps me understand it, though, because it's like, what is it pushing off of and what is pushing on it?

My go to example is if you're sitting in a kayak and you have a bunch of rocks, you can throw the rocks and you will go you will move in the opposite direction that you were throwing the rocks. And that is how planes work. They grab air and they throw it behind them. Rockets also throw stuff behind them, but they don't have any air to grab. So they have to carry the stuff that they throw behind them with them. It's like in a canoe as an airplane, you could reach into the bottom of the lake and pull

out a rock and throw it. If you were, if it was shallow, you could grab a rock from down there and then throw it and keep moving. That would be analogous to a plane grabbing air and throwing it behind itself. But a space canoe would have to have all its rocks with it already. Exactly. There's no lake bed to grab rocks from. Okay. Yeah.

And rockets get over this by carrying their rocks with them. That's why they call them rockets. I had all this stuff about air pushing in different directions and engine mechanics, but really all you need to know is throwing rocks. The most common, or a common type of rocket is with chemical combustion. So you have like the ingredients for a chemical reaction inside the fuel chamber. And then when those things react gradually over time, they create something that is more energetic and higher pressure environment so that it like squeezes out the back.

And that's what shoots because there has to be something throwing out the rocks. And in that case, it's like the chemical reaction is generating the energy that you need to to throw out the rocks. Right, because when the oxygen and the hydrogen or whatever the fuel is combined, they release a bunch of energy.

Squeeze it out the back. It's like a super soaker in a canoe. That's why Hank is the professional science communicator. Yeah. I need to come up with more weird metaphors. Yeah. I mean, for some reason, this has always, it always confuses me a little bit

because I need to be reminded that that me moving is also a force. Yeah. I think I, at some point in my academic career, crossed that mental hurdle where I'm constantly pushing against the air and the air is constantly pushing against me. Right. When I had to understand atmospheric pressure for the first time. And so then I was like, I'm always in a battle with air. The majority of questions that I get from TikTokers, the answer boils down to like, you have forgotten about air.

Which is easy to forget about. Like it's invisible. You're always touching it. You know, like it'd be very obvious immediately that something is wrong if it went away. Is that the answer to all their constant candle problems that they have air is a big part of their confusion about candles which is that candles become air what is hard i think oftentimes is that that like you can turn solid things into air things and air things into solid things that like when you burn a log like it doesn't mostly become ash only Only a tiny part of it becomes ash.

It's almost all becomes air. Okay. And logs are made out of air. Like trees take air out of the air and turn it into themselves. Yeah. Everything that a tree makes is just starts with air

and then it turns it into like leaves and wood and everything else that a tree needs. Yeah. It needs some dirt too, right? Somewhere along the way? No? Not really.

It's almost all the carbon dioxide. Otherwise, a giant tree would have a big hole around it. That is it, all the dirt. Oh, damn, you're right. I feel like I should get on TikTok just to learn how people get confused in science. I'm getting rusty now that I've been out of school. They cannot stop wondering why when you're inside a train

and you jump, you land at the same place. But if you're on top of a train and you jump, you land behind you. And I'm like- Okay, but why? Air! Air! It's the air again?

You forgot about air. Yeah, because all the air in the train is being carried forward with you. Oh. And all the air outside of the train isn't being carried forward with you. And so when you're outside of the train, being carried forward with you. Oh. And all the air outside of the train isn't being carried forward with you. And so when you're

outside of the train, it's very windy. All right. See you at the end of the episode. Bye. Okay, bye. Sam Buck final scores.

Sari and Hank and Stefan, we're all tied for second and Sam coming in. The natural hoarders. If you like this show

and you want to help us out, it's easy to do that. You can leave us a review wherever you listen. That's super helpful. Helps us know what you like about the show. Also, we look at iTunes reviews

for topic ideas for future episodes so you can leave those there. Second, you can tweet out your favorite moment from this episode. We love to see those. And finally, if you want to show your love

for SciShow Tangents, just tell people about us. Thank you for joining us. I've been Hank Green. I've been Sari Reilly. I've been Stefan Chin. And I've been Sam Schultz. SciShow Tangents is a co-production of Complexly

and the wonderful team at WNYC Studios. It was created by all of us and produced by Caitlin Hoffmeister and Sam Schultz, who also edits a lot of these episodes, along with Hiroko Matsushima. Our editorial assistant is Deboki Chakravarti. Our sound design is by Joseph Tuna-Medish. Our social media organizer is Victoria Bongiorno.

This week, but not in the future, we're sad to see Victoria moving on. And also we couldn't make any of this without 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. In October 2020, NASA sent a new $23 million toilet to the ISS for field testing.

It's 65% smaller and 40% lighter than the old model and was designed with input for the first time from female astronauts. One breakthrough is the ability for astronauts to pee and poop at the same time, which is my, okay, here's my big question of this but fact i always pee when i poop do astronauts have to learn how to not pee when they poop yeah that's one of the one of the tests they do they spin them in one of that those giant spinny things yeah and then they're like all right poop and don't pee or you're out of here buddy wow i wouldn't make it for many reasons, but that's one of them.

I think I could do it. I think I could do it too. I'm going to start trying and training myself.