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Speaker 1: Hello, and welcome to the short stuff. I'm Josh, and

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Speaker 1: there's Chuck and there's Jerry over there. We are reveling

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Speaker 1: in nature this morning. We're just loving life because it

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Speaker 1: has rained and it smells amazing outside. And it turns

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Speaker 1: out that that amazing smell is called petrochor. Chuck go, yeah,

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Speaker 1: And so we decided to have school outside today. Remember that?

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Speaker 1: Oh yeah, I loved that because it also meant not

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Speaker 1: only that it was a nice day out and that

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Speaker 1: your teacher had clearly taken acid that morning, but that

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Speaker 1: the the end of the school year was fast approaching.

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Speaker 1: Uh sure, because I guess that was usually in the spring, right,

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Speaker 1: especially in Toledo. Like if you if it, if it

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Speaker 1: was nice enough to go outside, you were coming up

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Speaker 1: on the end of the school year. So love that, yes,

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Speaker 1: But petro chor, like you said, if you ever go

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Speaker 1: outside after a rain, especially a light rain, which we'll

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Speaker 1: get to more so than a heavy rain. Uh And

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Speaker 1: you think, man, what is it about that smell that

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Speaker 1: I love so much? And we should also do one

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Speaker 1: on fresh cut grass? Okay, that's something similar, but that

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Speaker 1: has a name, and that is petrochor. P. E. T R.

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Speaker 1: I C h O R. And it is that earthy

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Speaker 1: sort of warm, steamy, earthy fragrance that we get. And

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Speaker 1: there is a story behind it and reasons for it

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Speaker 1: that is science based, yes, which makes it just amazingly wonderful. Yes.

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Speaker 1: But it came from Australia, right. The name it's did

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Speaker 1: Australia in the sixties. Actually, um, it's based on two

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Speaker 1: Greek words um Petro's I believe, which means stone, and

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Speaker 1: i corps, which means the fluid that flows in the

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Speaker 1: veins of the gods. Blood of the gods is a

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Speaker 1: simpler way to think about I also saw a life

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Speaker 1: force of the gods coming from a stone. They really

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Speaker 1: went all out, but they had great names. Well, at

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Speaker 1: least the woman researcher did Isabel joy Bear. I love

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Speaker 1: that name. It's just a wonderful little name, like it

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Speaker 1: should be a like Nickelodeon Sprout cartoon or something. And

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Speaker 1: that Isabelle joy Behar. That's different, right, That's like Kathleen

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Speaker 1: Turner overdrive. Anyway. The other guy was Richard Thomas, who

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Speaker 1: had a whole hum name. But the two of them

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Speaker 1: coined this term in ur in an article in the

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Speaker 1: journal Nature The article is called Nature of our Galacious

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Speaker 1: Odor with a you because they were in Australia and

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Speaker 1: they coined this term. But they also kind of got

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Speaker 1: down to what creates this and rather than it just

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Speaker 1: being one thing, it seems to be a combination of

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Speaker 1: three amazing things that all kind of come to the

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Speaker 1: four during a rainstorm, especially after a dry spell. The

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Speaker 1: first rain after a prolonged dry spell really stinks up

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Speaker 1: the place with beautiful odors. Yeah, And the first thing

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Speaker 1: that we're gonna talk about is a molecule that's made

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Speaker 1: by a certain kind of bacteria. And the molecule is

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Speaker 1: called geosmin g e O S M I N and

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Speaker 1: it's produced by the bacteria stripped to mices when it dies, right,

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Speaker 1: and it's all over the ground if it's you know,

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Speaker 1: healthy ground. And we figured out the stripto mices makes

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Speaker 1: a really good antibiotic. We use stripedo mices secure a

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Speaker 1: bunch of different stuff. But um, it's not stripped of mices.

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Speaker 1: Were smelling. It's this molecule that stripped of mices produces

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Speaker 1: as when it dies, and I believe as it's being

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Speaker 1: consumed by other bacteria. Right, So this geosman stuff that's

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Speaker 1: in the soil um has this earthy smell that the

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Speaker 1: the earthy component of petrocre is it comes from this molecule.

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Speaker 1: And they knew this starting back in the sixties with

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Speaker 1: Bear and Thomas, and they didn't know exactly how that

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Speaker 1: would happen though, like how does a molecule in the

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Speaker 1: soil get into the air to make it, you know,

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Speaker 1: the smell after a rain. And then finally some m

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Speaker 1: I T researchers proved it once and for all in

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Speaker 1: two thousand and fifteen, that it becomes aerosolized. Yeah, that's

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Speaker 1: really cool. Like just four years now as we record this,

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Speaker 1: we've known exactly how this happened because they used these

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Speaker 1: really high speed close up cameras to the ground and

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Speaker 1: they found out what the rain drops they trapped little

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Speaker 1: tiny air bubbles when they hit the ground, and then

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Speaker 1: those bubbles shoot up through the rain drop and kind

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Speaker 1: of pop an aerosol like uh, sort of when you

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Speaker 1: look at it when you pour a soda, that's stuff

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Speaker 1: that fizzes at the top. It just sort of aerosoli aerosolizes, yeah,

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Speaker 1: and it spreads by the wind, and that's why a

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Speaker 1: light rain makes the smell more like, if it's just

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Speaker 1: like pounding with rain, it's not gonna aerosize and aerosolies

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Speaker 1: and spread out as much, right, because it's diffused by

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Speaker 1: the wind. Like it pops up from the rain drops,

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Speaker 1: it pops through the rain drops into the air, and

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Speaker 1: then the wind kind of carries it. So if you've

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Speaker 1: ever noticed, especially before a storm, it's technically not smelling

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Speaker 1: before the storm. It's smells just at the very beginning

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Speaker 1: of the storm when the first droplets have hit the

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Speaker 1: ground and have begun to aristolize, but the wind is

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Speaker 1: really starting to pick up and carry it through. That's

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Speaker 1: where Geosman really comes into play. Yeah, and here's the

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Speaker 1: deal with Geosman. Why it's kind of a big deal

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Speaker 1: for us humans is that, more so than any animal

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Speaker 1: that I could find, human beings are really really sensitive

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Speaker 1: to the smell of Geosman. It's so bizarre, man, Like,

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Speaker 1: we're super sensitive. Yeah, I mean that means it's important, right,

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Speaker 1: it does. And they're not quite sure why it's important.

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Speaker 1: They think that maybe we evolved to be able to

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Speaker 1: find water through the scent of Geosman. It makes sense,

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Speaker 1: but um, so we're more sensitive Geosman than sharks are

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Speaker 1: to blood. Amazing. A shark can smell something like one

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Speaker 1: part of blood per billion parts of water, and we

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Speaker 1: can smell geosman at five parts per trillion. So we're

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Speaker 1: more sensitive to the smell of Geosman than a shark

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Speaker 1: is to the scent of blood in the water, right,

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Speaker 1: which I did some more research into that. Apparently sharks

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Speaker 1: have been overstated a bit. They can smell blood pretty well,

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Speaker 1: but it's not like those things where they can smell

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Speaker 1: it a mile away. That's all internet legend. Okay, sure,

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Speaker 1: but even still, I mean, the shark smells blood to

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Speaker 1: sustain itself with food, and we somehow evolved to smell

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Speaker 1: geosmen even better than a shark can. We're not known

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Speaker 1: for us since a smell. So there is a there's

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Speaker 1: a riddle there. There's a red flag evolutionarily speaking, that

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Speaker 1: we have yet to figure out. But it definitely is significant.

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Speaker 1: All Right, We're going to spend sixty seconds trying to

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Speaker 1: figure it out. You listen to this break and we'll

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Speaker 1: come back and figure it out and let you know. Alright,

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Speaker 1: so here's another cool thing the paper. But did we

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Speaker 1: figure it out? Now? We didn't figure it out. Okay,

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Speaker 1: here's the thing in that paper by Baron Thomas in

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Speaker 1: n s four. It's pretty cool. Uh. They found out

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Speaker 1: that this the scent was being captured and sold in

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Speaker 1: India as mettica atar and Geosman is also like becoming

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Speaker 1: a perfume ingredient, which is pretty amazing. Yeah, it has

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Speaker 1: been in India for a while, but the uh, I

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Speaker 1: guess the perfume industry in the United States and Europe

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Speaker 1: is finally catching up to that these days. Yeah, we

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Speaker 1: we love the smell, but we hate the taste as

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Speaker 1: as they say, yes, because Geosman also appears um in

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Speaker 1: other places, sometimes in the ter war of wine or

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Speaker 1: in mineral water. I don't know that, however, detected it

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Speaker 1: at least they didn't realize that. Yeah. I need to

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Speaker 1: know what it it is because I love beats, I

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Speaker 1: love mineral water. I certainly am made partially of wine.

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Speaker 1: So I need to know if, like all those things

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Speaker 1: that I like, if it's in there, then I probably

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Speaker 1: like to taste. So you do like the earthy taste

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Speaker 1: of beats, because that's what gives beats. It's earthy tastes

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Speaker 1: yours I do too, but I'm also like walking on

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Speaker 1: a razor's edge of enjoying beats every time I do

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Speaker 1: to where if I stopped and really thought about the taste,

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Speaker 1: I would hate it immediately and possibly forever. So I

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Speaker 1: just think about other stuff, like you know, baseball or

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Speaker 1: my old cabbage patch kid when I was younger. Interesting. Yeah,

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Speaker 1: I don't know about the second one, but yes, okay,

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Speaker 1: but that's not all, is it, Chuck. No, This this

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Speaker 1: next part is really cool to me, um, because if

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Speaker 1: you've ever noticed, if you've been in a rainstorm in

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Speaker 1: the country or the woods, it smells very different than

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Speaker 1: in the city. And that's not just because when it

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Speaker 1: rains in the city it's kicking up pee and poop

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Speaker 1: and garbage and stuff like that into the here. No,

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Speaker 1: because it's something. It technically smells cleaner in the city

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Speaker 1: than it does even in the countryside. Yeah, and that's

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Speaker 1: not because there's more to clean in the city, and

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Speaker 1: so you're smelling the offshoot of that. What it is

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Speaker 1: is ozone, that third ingredient that you smell when you

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Speaker 1: have that patricor effect? Is that a term? The the

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Speaker 1: effect of it effect up, Yeah, is lightning. So when

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Speaker 1: a thunderstorm comes around that what you're smelling with the lightning,

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Speaker 1: that clean, sort of crisp thing that you can't quite

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Speaker 1: put your finger on is ozone, Yeah, which is produced

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Speaker 1: naturally up in the atmosphere. But the electrical like bolt

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Speaker 1: of anger that is lightning also excites the oxygen molecules

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Speaker 1: in there so much that it combine them together into

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Speaker 1: oh three, that's ozone, and that does have a very

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Speaker 1: specific smell. It's weird. It's a weird smell. I remember

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Speaker 1: we had a listener one time that was, um, do

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Speaker 1: you remember this guy he was making O owned deodorant. No, yeah,

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Speaker 1: he sents. I think he sent it to me because

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Speaker 1: he knows that I have deodorant problems. Oh I want

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Speaker 1: to try that. Who if you're listening please years ago.

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Speaker 1: But if you're listening citizen some more. I didn't care

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Speaker 1: for it. Had a weird smell, and he was like, yeah,

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Speaker 1: some people ozone's kind of goes one way or the other.

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Speaker 1: I'll use your old stick if you're not using it anymore.

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Speaker 1: I don't think you want my four year old ozone

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Speaker 1: deodan Yeah, yeah, with like your armpit hair is still

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Speaker 1: stuck to the top of it. Oh gosh. Um. So

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Speaker 1: the reason why it smells cleaner in the city is

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Speaker 1: because there's less geosman, because there's typically less soil in

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Speaker 1: the city and geosman smells more earthy than ozone. Um.

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Speaker 1: So you get more of a prominent geosman smell in

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Speaker 1: the countryside, which means you get more of an ozone

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Speaker 1: smell in the city, which means it smells cleaner in

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Speaker 1: the city. Yeah, it's not like there's more ozone in

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Speaker 1: the city, is just more prominent because there's less of

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Speaker 1: the geosman, right, right, But there is another ingredient and

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Speaker 1: we skipped over it's technically the second ingredient. And they're

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Speaker 1: not sure of this, but it's just it makes so

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Speaker 1: much sense that they're almost certain that this is the case.

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Speaker 1: That the third component of petroc or you've got geosman,

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Speaker 1: ozone and then tirpenes, the things that give plants their

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Speaker 1: distinctive smells. They think that tirpenes are activated through a

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Speaker 1: number of different mechanisms um that make them produce a

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Speaker 1: much more fragrant smell right around a rainstorm. Uh, and

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Speaker 1: then that contributes to the smell of petrocre to right,

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Speaker 1: and if it's been like really dry for a long time,

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Speaker 1: that rain may be hard enough to where it like

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Speaker 1: breaks off dry plant material and stuff like that releases

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Speaker 1: that chemical uh, and they like in it. In this

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Speaker 1: article from the BBC, just like when you crush up

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Speaker 1: dried herbs, it releases that smell. Yeah, and it would

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Speaker 1: probably follow the same process as the geosman where it

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Speaker 1: just becomes airsolized by the raindrops as they hit them.

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Speaker 1: Very cool. This is a good one to know. Like,

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Speaker 1: next time you're in a rainstorm and someone comments about

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Speaker 1: why it smells, just say patricor or the next time

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Speaker 1: was somebody just spits out a bite full of food

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Speaker 1: in their napkin and says, I hate beats. You can

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Speaker 1: explain what petricor right, Well, that's it for petrocor, patricor

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Speaker 1: whatever you want to call it. Uh, it has been done.

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Speaker 1: So short stuff is out. Stuff you should know is

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Speaker 1: a production of iHeart Radios How Stuff Works. For more

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Speaker 1: podcasts for my Heart Radio, visit the iHeart Radio app,

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Speaker 1: Apple Podcasts, or wherever you listen to your favorite shows.

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Speaker 1: H