SciShow Tangents - Rocks

Starting point is 00:00:00 Hello and welcome to SciShow Tangents, the lightly competitive science knowledge showcase. I'm your host, Hank Green, and joining me this week, as always, is science expert, Sari Reilly. Hello. And our resident everyman, Sam Schultz. Hello there. When did you two know how good you were at singing, for sure? Like, when did you decide, I am this amount of good at singing? Never. Not once. Did you realize at some point that you think you are bad at singing i think i'm really good at singing when i'm drunk really good i love to sing is your opinion of your singing waivers could it's context dependent yeah i would never sing in front of anybody sober and i've sung in front of hundreds of people drunk i don't think i've ever seen you sing i don't think i've seen you sing you've never you've definitely never seen me drunk enough to sing. Sam!

Starting point is 00:01:07 We can work on that. Yeah? Let's get you drunk! Oh, I don't like this. I don't like that everybody knows this now. The most embarrassing thing to happen to me is that someone will learn something about me. Oh! Horrible.

Starting point is 00:01:20 That's the saddest thing ever. You need to tell your friends things about you. I've always been very sort of waffly about my singing because I remember singing in the car one time and my family making, I thought I was doing great. And they made all kinds of noises about how it wasn't so great. And that kind of set me back a little bit. And then my wife is a very good singer. She's trained and everything. And at one point when,

Starting point is 00:01:49 after I had been a professional musician and the lead singer of a band for several years, she said, you're a good singer. And I was like, I am? So that's what I knew. That's what I knew for sure. I do think you're a good singer yeah thanks i i definitely it's context dependent whether i think i am and also whether i am i think mine is also heavily context dependent especially in my formative years because i just believed what

Starting point is 00:02:19 anyone said about me so similarly sylvia is a trained singer and we i we like make up ditties around the house constantly and so i like went into this being like i'm a horrible singer uh-oh but we just like make up songs and she was like you're actually kind of good you sang that really nice song about weather yeah well yeah that was it that and that was because of sylvia's bullying of like i think i can do this. And she was like, you definitely can. And then she practiced with me. And she was like, you can do it.

Starting point is 00:02:49 Nice bullying. Yeah, nice bullying. Like the, you know, spouse bullying when you need it. Constructive spousal bullying. Encouragement? Is that what it is? Yeah. Yeah.

Starting point is 00:03:02 Encouragement. It can feel like a bit much sometimes, the encouragement. That's true. So today's episode of SciShow Tangents, as you might expect, is not at all about singing. Every week here on Tangents, we get together to try to one-up, amaze, and delight each other with science facts while also trying to stay on topic. Our panelists are playing for Glory and for Hank Bucks, which I will be awarding as we play. And at the end of the episode, one of them will be crowned the winner. Now, as always, we're going to introduce this week's topic with a traditional science poem.

Starting point is 00:03:30 This week, it's from me. Everything has a point at which it will freeze. And for water, that's around 32 degrees. Colder than that, and it's no longer wet. Instead, it's harder than some rocks get. Which brings up a thing about which I like to talk. If water ice is or is not a rock, and not just water ice, but all of the ices, because we need a definition to get any preciseness.

Starting point is 00:03:53 Dry ice on Mars or methane ice on Pluto, a hunk of solid stuff that can be bigger than a yugo. It's naturally occurring on the surface of a planet. Is it less of a rock than just normal rocky granite? Because granite melts too, just like water does. So rocks can freeze or melt. So what's the difference, cuz? And because... Okay.

Starting point is 00:04:15 I worked. And if melted rock is lava, that leaves me here to ponder. If I'm made of melted ice, then am I a lava monster? You came back a little bit with the end. The cuz was the weak point of that poem. The cuz, I worked, there was a long period of time where I was stuck on that line

Starting point is 00:04:38 and I just, I needed to get to the podcast. It was five minutes late. And I just says, I put in a cuz i liked it thanks i liked how embarrassed it made you and you said it mostly i couldn't get through it anyway the topic of the episode is is is rock rocks and i've been wondering for some time if we can consider ice a rock which it seems that we can in in that case, can we consider water lava? Which, why not?

Starting point is 00:05:06 I'm sure there must be a reason, though. But for me, I don't want to hear the reason. I want to be a lava monster. The backbone of science. He's just not listening to reason. It's just whatever you want. Sari, maybe you can help if you explain to us what are rocks? Yeah.

Starting point is 00:05:26 So I think ice is more of a mineral than a rock from what I can understand. That sounds like a mineral sounds like a rock. Keep going. A mineral is similar to a rock, but from what I can find, and I did not talk to any geologists and it's very dicey. A lot of people have strong opinions like you,ank about rocks and minerals and whatnot but it seems like there's a consensus that a mineral is an inorganic element or compound so doesn't have carbon hydrogen oxygen those three make up like organic chemistry so you're telling me coal isn't

Starting point is 00:05:59 a rock no i don't think so bs carbon containing. Carbon containing. Yeah. Or not, oxygen is not in there, but like, yeah, carbon containing. But minerals are inorganic compounds, so they don't contain carbon inside. And I think that's why ice would be a mineral because it has an orderly internal structure and like a homogenous chemical composition. It's made out of one thing, H2O. It's made of one type of molecule right so so in that case like a crystal also wouldn't be a rock yes like calcite is all calcium carbonate and it is considered a mineral how much stuff do i have to put in my ice for it to become a rock

Starting point is 00:06:39 you have to put one more thing you have to mix ice with like a popsicle, maybe a rock, because it has ice and then like a flavoring in it. Yeah, but then it's not naturally occurring. So it's not a rock. A naturally occurring popsicle. Yes. Which is basically just me if I froze to death. Yes. So when you're dead, you can become a rock if you'd want.

Starting point is 00:07:00 No, except I'm carbon contained. Oh, yeah, you are. So is that a problem? Because I'm organic, unfortunately. You have to become inner. If your bone got wet. No, your bone has carbon in it, right? Yeah, we got to get away from carbon.

Starting point is 00:07:15 What I'm hearing is I'm not a rock. You're not a rock. Rocks are made of two or more minerals, but also still inorganic. And that's about it. It could be a solid mass. And like, at what point is it solid? Cause it's all mixed together and the atoms are bonded or like an

Starting point is 00:07:31 aggregate of smaller things. And as far as I can tell, a rock is a stone is a pebble and it just all has to do a size. Like we all, they all mean the same thing. So like a grain of sand is just a really small rock. yeah sand as long as it's not just silicon dioxide it's got something else in there it's got to have something that sounds like a bunch of bs to me i'll be honest with you i think crystals should be rocks i think that water should be rock uh i don't see why we got

Starting point is 00:07:59 to be so picky about it why do you want all this stuff to be rocks? Just for fun? Yeah. Okay. For the purpose of this podcast, we can Occam slap chop rock so that anything inorganic is a rock. That's what we do every episode, though. Everything turns out to be everything every episode. Occam slap chop, everything is everything. Don't ask questions. Sari, do you know anything about the origin of the word rock? Much like its definition, the origin of the word rock is mysterious.

Starting point is 00:08:33 Yes. What happened was, actually, I know this one, is there was a man, his name was Dwayne Johnson, and he was so strong and big and hard that they named all of the other rocks after him. And he was so strong and big and hard that that radiated back in time and forward in time. Yes. Yeah. Okay. That makes sense.

Starting point is 00:08:53 Uh-huh. Yeah. Yeah. Dwayne the Rock Johnson is actually a time traveler. You'll see him showing up in like old recreations, but he's like the mountains. Just on the side of the pyramids. Yeah. He's kind of fourth dimensional. He's just throughout time and like intersecting it in

Starting point is 00:09:09 a different way than the rest of us do. Did you find anything else about rocks in their etymology? I could give you origin words. The earliest form of rock that we could find was medieval Latin or vulgar Latin, rocca, R-O-C-C-A. And back in the day, using rock was more for big things. Like you'd say, ah, that's a very big rock. And it would be a no-no to use rock for something that you could carry in your hand. So stone, which also is a mysterious origin, because my guess is, as we walked around and we were like, what's that? A rock, what's that? A stone, what's that?

Starting point is 00:09:46 A pebble. And then all of a sudden people were arguing about it and they had to draw some lines somewhere. But a stone is just like a hand-sized rock. And now in modern day, then we've kind of separated, like a rock is kind of chunky, a stone is kind of smooth, a boulder is kind of big. It's still like a unit of measurement, right? It's like a rock is kind of chunky a stone is kind of smooth a boulder is kind of big it's still like a unit of measurement right it's like a weight measurement is that like as heavy as a hand-sized

Starting point is 00:10:11 rock supposed to be significantly heavier i think it's in the it's in the double digits pounds yeah okay 14 14 pounds exactly yeah i don't know where that came because we're so bad at units couldn't make it 15 that would have at least been like a number you could represent on hands. Couldn't have made it 10. That would have been metric. No, 14. Not 14 point anything, though. Because we at least got that together.

Starting point is 00:10:38 Well, I bet someone had a rock. Someone rich had a rock. That was around 14 pounds. That was around 14 pounds. And it was like, like oh here's my stone i can pick it up so it's not a rock it's a stone and like i'm gonna buy your goat how heavy is your goat i don't know well my stone weighs this much so i'm gonna weigh your goat this is a unit of weight not of currency currency. Why are we buying things?

Starting point is 00:11:06 I don't know. No, sorry. We're weighing the goat to see its value. I don't know. I could have chosen something that you would buy more about weight rather than a goat has intrinsic value. I thought that you were trading a stone for a goat. Yeah, it's 14 pounds, like the pre-euro currency. Because pounds is currency. Yeah. They still have pounds. They the pre-euro currency. Because pounds is currency.

Starting point is 00:11:27 Yeah. They still have pounds. They didn't get rid of those. They're naming conventions, man. It is very, very good. That's why they have stone is because they use pounds for their money. And they're like, uh-oh. They really need to get their act together.

Starting point is 00:11:41 My last rock fact is that the name Petereter comes from rock and i love that i didn't know that uh because i wasn't i never studied the bible but comes from like petros like um petrology study of rock so when you name your child peter you're naming them rock which i think peter parker rock man Dwayne Peter Johnson. Well, I guess that silence at my joke about Dwayne Peter Johnson means it's time to move on to the quest portion of our show. This week... Well, I was going to cut it out for you, but now I got to keep it.

Starting point is 00:12:22 This week, we're doing Tangents Rocks, Truth or Fail. So when you were a kid, you probably played with some rocks. You maybe even formed emotional bonds with them as you were carrying them home and then put them in a special pot just for the rocks that you made friends with. Maybe that was just me. Or you could have skipped a stone across a pond. And if you think about it, these were all little rock experiments. across a pond. And if you think about it, these were all little rock experiments. And it turns out that there are scientists who grew up and decided to continue playing with rocks, all in the name of experimentation. So the following are three stories about experiments

Starting point is 00:12:53 scientists have done that involved rocks. But two of them are big fat lies. Tell me which one is the true one. We got a story number one. A team of archaeologists studying ancient Greek ruins were trying to decide whether marble remains had originally been part of a mountain temple that was destroyed during an ancient rock slide. So the archaeologists created their own miniature rock slide by sending chunks of marble down an inclined treadmill to see how the marble broke when it landed. Or it could be, fact number two, a behavioral economist wanted to see how the marble broke when it landed. Or it could be, fact number two, a behavioral economist wanted to see how people change their shopping habits

Starting point is 00:13:28 based on the amount of stuff they bring into a store. So they set up an experiment where people carried a purse as they went grocery shopping. Unbeknownst to the subjects, some of these purses had a secret pocket that the economist would fill with different amounts of rocks so they could see if the weight of the bag would impact the subject's willingness to buy more stuff. Or it could be fact number three.

Starting point is 00:13:52 When astronauts returned from the first trip to the moon, NASA wanted to make sure that they didn't bring anything dangerous back with them. So they took some of the lunar rocks that the astronauts had brought back with them and ground the rocks into dust. And then they added the moon dust to some food and fed it to cockroaches Wow. That's bananas. So is it story number one, an ancient rock slide treadmill? Story number two, a pocket full of rocks?

Starting point is 00:14:22 Or story number three, a moon dust diet for cockroaches can't be any of those right the rocks the purse the purse rocks those rocks are so incidental to the story i'll be disappointed if it's the purse rocks it could have been anything could have been marbles you know marbles would have been louder than rocks i feel like if you put one big rock Marbles would have been louder than rocks. I feel like if you put one big rock, it's just heavy. Marbles, you're like, what's in here? A surprise?

Starting point is 00:14:53 And I think a treadmill's not strong enough to smash a marble. Well, at an incline, maybe. So it's kind of falling down, too. You got to use specific marble, I think. I think it's going to smash the treadmill up first. But the cockroach one, that one just seems like good science to me. Take some of the most valuable objects on earth, feed it to a cockroach. Yeah.

Starting point is 00:15:17 Just in case it's going to mutate them. You want to know if you're going to get mutated. That sounds absolutely baloney to me. I wouldn't feed rocks to a cockroach. Would they even eat it? Would they be like, what's this dust? Yum, yum, yum. They put it in food.

Starting point is 00:15:33 Oh, you like mush it in like you hide a pill in your cat food. Yeah, until you get a pill pocket and put moon rocks in it. I don't know. This is truly a crapshoot. I'm going to guess the marble one because it sounds weird enough that I think people drop things all the time and they break.

Starting point is 00:15:50 Sam? Oh, I'm going with the moon dust one for sure. Sam's going with the moon dust. Well, here we have our true fact for you. When astronauts came back

Starting point is 00:15:58 on the Apollo 11 mission, they brought back with them around 49 pounds of lunar material. And NASA wanted to make sure it wasn't nasty stuff. So in addition to quarantining the astronauts for a period of time, NASA decided to test out the rocks to see if there was anything dangerous in them.

Starting point is 00:16:12 And they did that by feeding them not just to cockroaches, but a bunch of different animals, including Japanese quail, brown shrimp, oysters, and German cockroaches. NASA scientists ground the rocks into dust and then got it into the animals in a number of different ways for 28 days. Some of it, like mice and quail, they injected it into the animal, and some was added to the water that the aquatic animals were living in, and some was mixed in with the food that the insects, like German cockroaches, were eating. None of the animals seemed to react particularly negatively to the moon dust, except for the oysters.

Starting point is 00:16:47 And maybe that was just because it was their mating season. The samples did not turn up any moon microbes either, assuring the scientists that the samples were probably not dangerous. They kept doing this until Apollo 14 in 1971, after which they stopped taking moon dust and sampling animals with it. Did any of them ever lick it? Somebody's licked it, right? Oh, some geologists lick things all the time.

Starting point is 00:17:10 Somebody's licked the moon rock. Okay. Maybe they have like one special moon rock that everybody licks. Yeah. You don't want to like ruin all of them with like your lick dust. Uh-huh. But there's a special moon rock. It's like the Barney stone that everybody kisses.

Starting point is 00:17:24 It's like that, but it's for geologists. You're allowed to lick this one. The rest. You can lick this one. Forbidden fruit. We'll go get the licking rock. Welcome to the moon rock room. Would you like to lick the licking rock?

Starting point is 00:17:37 The other two facts were based on absolutely nothing and were entirely made up. Wow. Treadmills exist and purses have rocks in them sometimes. There you go. That's all you need to know. Next up, we're going to take a short break and then it'll be time for the fact off. Welcome back, everybody. We got one point for Sam, zero points for Sari.

Starting point is 00:18:15 Now, get ready for Fact Off. Our panelists have brought science facts to present in an attempt to blow my mind. And after they have presented their facts, I will judge them on which one was more mind-blowing and which one is going to make a better TikTok. And to decide who goes first, I have a trivia question. There have been many memory rocks throughout human history, but there are two in particular that loom large in our culture. One is the immense stone structure known as Stonehenge, which was built around 5,000 to 4,000 years ago with different stones hauled from miles around. The largest of these stones are called sarsens, and they can be up to 30 feet tall.

Starting point is 00:18:51 The other memorable rock is, of course, Dwayne the Rock Johnson, wrestler and actor extraordinaire. So how many Dwayne the Rock Johnsons would it take to equal the weight of one sarson? I love this. I'm trying to remember how to do long division. So you need long division? You just need multiplication, Sam. Oh, yeah, you're right.

Starting point is 00:19:11 Okay, wait. Are you doing math on a piece of paper? Yeah. Well, I'd better start thinking. 50 rocks. Is it 50 rocks? Well, I don't know. Sarah's going to have to tell me her answer first.

Starting point is 00:19:24 Oh, I'm going to guess 100 Dwayne Peter Johnsons. rocks well i don't know sarah's gonna have to tell me her answer first oh i'm gonna guess a hundred duane peter johnson's in one sarson the answer is 192.31 duane the rock johnson's per sarson i that's probably more significant digits than is appropriate uh a sarson weighs around 25 tons and the rock weighs around 260 pounds big guy guy i love the 0.31 and chop off a leg stick it on there and then that equals a sarson i'll go first with this mighty victory all right so there is such pure nerdy joy in picking up a good rock and holding it in your hand and being like, wow, what a good rock. And that probably, or so I'm speculating, is how human ancestors found good rocks for tools and realized how some were better for smashing and some were better for, their chemical composition, what they're made of, and how those atoms are bonded together to give it different properties, from a soft, powdery surface that flakes off easily in something like chalk, to a really strong crystalline structure in something like granite.

Starting point is 00:20:35 Granite is an igneous rock, which means it forms from cooling magma or lava. And even though there's a lot of granite with a lot of variation, all granitoid rocks have that recognizable spotty texture because those are crystals that formed as it cooled relatively slowly under the earth's surface as opposed to being flung out of a volcano and cooling quickly in air so somewhere around 61 million years ago the earth's crest was shifting around europe and greenland and a pretty unique kind of microgranite formed with really small crystals that were rich with alkali metals, which are the things in the first group of the periodic table like sodium. And what this means in not so geological terms is that these microgranites

Starting point is 00:21:15 are really strong and chemically stable, so they don't erode easily. They also don't absorb water very easily at all, which prevents big cracks or chips, making it a perfect material for curling stones. Yes, those hunks of rock that are polished so smooth that people toss across ice and brush brooms in front of to score points. I'm not a huge sports person, but curling is weird and fun to watch because so much of it is about precise physics and friction and like, what a bizarre concept. So in the olden days, I think curling rules were a little looser and people would just hurl rocks of different shapes andilsa Craig, because the rock is so perfect for what the athletes put it through. So I guess when you're setting up a tent, you just grab a random rock and smash in the stake. But when you're an ice athlete, you need the fanciest granite on the planet to do your sport well or fairly.

Starting point is 00:22:22 Could we run out of curling stone someday? We could, right? Yeah, we have to make sure that the sport doesn't get too popular. to do your sport well or fairly. Could we run out of curling stone someday? We could, right? Yeah, we have to make sure that the sport doesn't get too popular. Yeah. Yeah, I think they have limits on how much can be mined at a time. So I think they had a big batch

Starting point is 00:22:35 that was mined around the early 2000s that was supposed to last until 2020. And then they mined another batch that is supposed to last like another decade or so. So they are very carefully monitoring this micro granite. But the thing is, you don't like go through them, right? You don't like use one up.

Starting point is 00:22:52 You have to be doing it real wrong, I think. Yeah. That's why it's so good because if you used other kinds of granite, then your stones might wear down or water might seep in and turn into ice and like chip off pieces. But this is the good stuff. Right. A generational curling stone. might wear down or ice might uh water might seep in and turn into ice and like chip off pieces but this is the good stuff a generational curling stone you don't get buried with one of these you pass it down all right weird not what i was expecting at all sam the popular depiction of bees in media from winnie the pooh to the bee movie is that they're friendly little fellows who live in

Starting point is 00:23:22 big hives with their family and do teamwork. But the reality is that most bees are solitary. They do not do teamwork and they do not live in big hives with anyone. Solitary bees mostly live in holes in the ground, but many of them also drill holes into things or find naturally occurring cracks to live in and lay their eggs in. Commonly known as mason bees, one particular type, typically burrow into things like wood, which is, you know, hard, but like soft at the same time. Sure. Something you could see a bee going really chewing into,

Starting point is 00:23:52 or they, they do it in clay as well. Also soft enough. You could see a bee doing that. But this episode, as you may remember, is about rocks. In 2015, a doctoral student named Michael Orr was looking through rock samples and discovered something weird he found sandstone samples that were full of holes drilled by mason bees and it turned out that a bee scientist named frank parker had collected the rock samples and written research on these rock dwelling bees in the 70s but had never published the work and so what's so cool about that is that nobody since then had ever observed bees drilling into rock that anybody knew of.

Starting point is 00:24:28 It was just this paper hidden away somewhere. So, or which is a great rock related name, by the way, for this episode, retrace Parker steps, which took him to the San Rafael desert in Utah. And he found the exact same rocks that Parker was writing about.

Starting point is 00:24:43 And lo and behold, there were still Mason bees living in those exact same rock holes that there were living there in the 70s. So after that, several more nests of the same bee species were found in Utah, Nevada, California, and Nevada, I wrote twice. So maybe somewhere else, who knows? Or he went back to Nevada and said, hey, I found some more. The bees were dubbed Anthrophora Pueblo, I assume in reference to the cliff face shelters built by some of the Puebloan people of Southwest North America. So you might think that this new bee species has some pretty specialized physical traits to allow them to chomp into rocks. Sure.

Starting point is 00:25:17 Like the strongest of mandibles. But I think they pretty much just have the regular mandibles of any bee. And older bees have been observed with very worn out mandibles from biting rocks. But they are able to use a pretty cool tool to help them wear the rocks down. The bees suck up water and spit it on the sandstone to help dissolve the carbonate crystal that binds the sand together. So that makes another bee first. The first time bees have been observed using water to help them build nests. But why rocks, you may ask well rocks are really good at being hard which protects the bees and their

Starting point is 00:25:50 babies from weather but their rock homes also provide protection from a couple of nasty interlopers one is all the bacteria and stuff that can grow in organic nesting material and hurt their babies and the other is parasitic beetle larva that can end up in nests and in softer Mason bee nests, the larva can infiltrate multiple cells and infect multiple babies. But these much more literally Mason bees cover up holes of infected bee babies with basically concrete. They can just like slather over goopy sandstone that hardens into something

Starting point is 00:26:22 that's too hard for the larva to burrow their way out of. So there's less to mate and they can't get into other holes. So they lose that one egg, but the whole nest is safe. And their mandibles get worn down. They're like, how do they do it? Are they special? And it's like, no, look, they got little nubs left after all the rock chewing that they've done. Yeah, but it was worth it. So what you're telling me is now I have to pick between bees chewing through rocks and whatever Sari told me. Oh, no. No, and the special Scottish island that is the only place to make good curling stones, at least according to the people who run the special Scottish island.

Starting point is 00:27:02 Yes, to the Olympic Committee. So the Olympic Committee requires them to come from this island? Yes. There's other like micro granite, like a couple other places, but they are much, much less used, I think. Sam, I think you're the winner of the episode. It was hard. That's a difficult choice, but you got the point in the first one. So it puts you over the edge.

Starting point is 00:27:24 Turns out rocks are fun i like rocks i wrap my head around rocks there's plenty of them and now that means it's time to ask the science couch we've got some listener questions for our virtual couch of finely honed scientific minds and emmy rose on discord and also at candy cane reads asked do geologists really lick rocks? Can you lick bones to tell them apart from rocks? And the answer to that question is yes and yes. Am I right? Yeah, you're right. Do you know why?

Starting point is 00:27:53 Hey! Have you licked bones and rocks? I have. And I do detect the difference. Though I feel like there has to be some situations in which like some rocks probably are pretty similar to bones. So this feels different on your tongue? Yeah, because bones are like have more pores. And so your like tongue kind of sticks to it more.

Starting point is 00:28:12 Yeah. And by bone, you mean fossils? Fossilized bone, yeah. Okay, cool. When a geologist looks a rock for science, it's just a little bit. It's just like another metric by which you can tell what you're looking at. Sort of like you look at the color or you look at the texture or you look like what intrusions are in there or what shape it is. So I think when people think licking rocks, they think like a lot of licking. It's not very much. Like an ice cream cone or something.

Starting point is 00:28:45 of licking, it's not very much. Like an ice cream cone or something. Yeah, not an ice cream cone. And like Hank mentioned, fossilized bone can be distinguished from rock, even though they might look similar. Like that's where you'd lick it is like, oh, I'm not sure if this is a fossil or not because of the pores. And as far as like the reason why, I think it's similar to why tape is sticky, where it's like tape has a watery adhesive and that seeps into the pores and then you can't pull it away as easily. And so I assume that's what's happening with your tongue and the porous bone or a porous rock. Like porous rocks will also be a little bit stickier. And there are ways like you could tell a slightly porous rock or a dry and airy rock from a denser rock based on lichen as well. And it's like one thing that can contribute to a rock's positive identity.

Starting point is 00:29:33 The other thing is that we don't really have great chemoreceptors on the outside of our body. Like you can't really smell to the same degree as you can do other things and like you can touch but like a really like their most chemical sensitive parts of our bodies like our tongue and so you can detect small bits of flavor or like different trace amounts of different chemicals and so like this is really clear if you're working with halite which is sodium chloride which i guess is a mineral but looks a lot like quartz and especially if you're like with halite, which is sodium chloride, which I guess is a mineral, but looks a lot like quartz. And especially if you're like more of an amateur, just like white and clear. And if you lick it, it'll taste salty as opposed to nothing. This is sort of coming back to just the feeling that the tongue is exceptionally good at stuff. And it is a thing that we do not give enough credit to, nor think enough about how amazing it is.

Starting point is 00:30:26 Though maybe it's a little upsetting to think about how amazing it is. Because it is kind of gross to have a tentacle in your face that is always wet. So you kept saying it was one of the ways you tell rock stuff. Is it like one of the main ways? Is it like the biggest one? I would say it's a last resort kind of thing. Oh, that's too bad. So a lot of the ways that you can ID specimens, I don't know.

Starting point is 00:30:51 I feel like our color is very obvious, but then you try and identify whether there are crystal chunks in it or what it's made of. Because if a rock is made of multiple minerals, you try and see what it's composed of. You can break it down into like sedimentary, igneous or metamorphic, where sedimentary is like squished sand together. Igneous is volcanic and then metamorphic is like it formed and then got squished and heated up a lot and changed because of that.

Starting point is 00:31:24 So yeah, I think there are a lot of other more prominent ways to detect rocks. And I don't think you'll be reading any scientific papers where people identified something by lick. But speaking of the tongue being a wet tentacle, another way to examine rocks is wettability, which is how water adheres to the surface or sometimes like getting a rock wet, like in the way of dunking your hand with a river rock underwater and then bringing it up. You can see things that you wouldn't be able to see when it's dry. Just I mean, just spit on it. You don't have to put the tongue on to it. There's ways to get liquid out of your body and onto something else without direct application.

Starting point is 00:32:06 Yeah. I cited some like Twitter threads and blogs because I had to find scientists talking about this. But one of them was like, you know, you can just lick your finger and then touch it to the rock. You don't got to make tongue contact with the rock if you don't want to. Nobody's having any fun out there. Yeah. And look, what's on the rock that's going to be dangerous unless the rock itself is made out of poison which it could be yeah yeah

Starting point is 00:32:30 that's the other thing you could lick a poisonous rock and you might be like uh a soluble copper sulfate and it'll taste a little sweet but it'll be like that's poison or arsenic all right so what you're saying is if i don't know what i'm doing, I shouldn't go around licking every rock. Yes, correct. Okay, great. That's what I'm taking away. Don't lick things you don't know things about, I guess. That goes for rocks and it goes for people. If you want to ask the Science Couch your question, you can follow us on Twitter at SciShowTangents, where we'll tweet out topics for upcoming episodes every week. Or you can join the SciShowTangents Patreon and ask us on Discord.

Starting point is 00:33:07 Thank you to at MXDemoUnicorn, Falafi, and everybody else who asked your questions for this episode. If you like this show and you want to help us out, it's really easy to do that. First, you can go to Patreon.com slash SciShowTangents, where you can become a patron and get access to things like our newsletter and our bonus episodes. Second, you can leave us a review wherever you listen. That's helpful, and it helps us know what you like about what we do. 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.

Starting point is 00:33:37 And I've been Sam Schultz. SciShow Tangents is created by all of us and produced by Sam Schultz, who edits a lot of these episodes, along with Seth Glicksman. Our story editor is Alex Billow. Our social media organizer is Paola Garcia Prieto. Our editorial assistants are Deboki Chakravarti and Emma Dowster. Our sound design is by Joseph Tunamedish. Our executive producers are Caitlin Hoffmeister and me, Hank Green. And 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.

Starting point is 00:34:21 But one more thing. Shipworms aren't worms as long and gooey as they look. They're actually a bivalve like a clam with two small shells surrounding their mouth. And they get their name because they grind up rotting wood and dig out a tunnel to live in, just like the bees, while eating a woody snack along the way. In 2019, researchers announced the discovery of a new kind of shipworm in a river in the Philippines, one whose shell mouth is tough enough to dig into hard limestone rocks just like the bees it doesn't seem like they're getting any nutrients from the limestone they eat but because what goes in must come out the limestone goes

Starting point is 00:34:55 straight out their butts because they excrete a mineralized coating that lines their home tunnel and poop out lots of sand that coats the bottom of the river. Wow. Wow. Well, what are they eating then? You know, all the other stuff. Okay. Just grime that floats by? Yeah, probably. In trying to find this butt fact, I googled rock eating and then it auto-completed to rock eating pancakes.

Starting point is 00:35:17 And so, like, my first thought was, that's weird. Like, what are pancakes that eat rocks? Is this a meme I haven't known about? It's Wayne the Rock Johnson eating pancakes. It's just a bunch of pictures of him eating pancakes. That's a man who can take down a few pancakes.

SciShow Tangents - Rocks

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