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Short Stuff: Petrichor · Stuff You Should Know

• 0:04
  Speaker 1: Hello, and welcome to the short stuff. I'm Josh, and
• 0:07
  Speaker 1: there's Chuck and there's Jerry over there. We are reveling
• 0:09
  Speaker 1: in nature this morning. We're just loving life because it
• 0:14
  Speaker 1: has rained and it smells amazing outside. And it turns
• 0:18
  Speaker 1: out that that amazing smell is called petrochor. Chuck go, yeah,
• 0:22
  Speaker 1: And so we decided to have school outside today. Remember that?
• 0:26
  Speaker 1: Oh yeah, I loved that because it also meant not
• 0:29
  Speaker 1: only that it was a nice day out and that
• 0:31
  Speaker 1: your teacher had clearly taken acid that morning, but that
• 0:36
  Speaker 1: the the end of the school year was fast approaching.
• 0:39
  Speaker 1: Uh sure, because I guess that was usually in the spring, right,
• 0:42
  Speaker 1: especially in Toledo. Like if you if it, if it
• 0:45
  Speaker 1: was nice enough to go outside, you were coming up
• 0:47
  Speaker 1: on the end of the school year. So love that, yes,
• 0:51
  Speaker 1: But petro chor, like you said, if you ever go
• 0:54
  Speaker 1: outside after a rain, especially a light rain, which we'll
• 0:57
  Speaker 1: get to more so than a heavy rain. Uh And
• 1:00
  Speaker 1: you think, man, what is it about that smell that
• 1:03
  Speaker 1: I love so much? And we should also do one
• 1:05
  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.
• 1:12
  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
• 1:44
  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
• 1:51
  Speaker 1: force of the gods coming from a stone. They really
• 1:54
  Speaker 1: went all out, but they had great names. Well, at
• 1:57
  Speaker 1: least the woman researcher did Isabel joy Bear. I love
• 2:01
  Speaker 1: that name. It's just a wonderful little name, like it
• 2:03
  Speaker 1: should be a like Nickelodeon Sprout cartoon or something. And
• 2:09
  Speaker 1: that Isabelle joy Behar. That's different, right, That's like Kathleen
• 2:14
  Speaker 1: Turner overdrive. Anyway. The other guy was Richard Thomas, who
• 2:17
  Speaker 1: had a whole hum name. But the two of them
• 2:19
  Speaker 1: coined this term in ur in an article in the
• 2:23
  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
• 2:31
  Speaker 1: they coined this term. But they also kind of got
• 2:33
  Speaker 1: down to what creates this and rather than it just
• 2:36
  Speaker 1: being one thing, it seems to be a combination of
• 2:39
  Speaker 1: three amazing things that all kind of come to the
• 2:43
  Speaker 1: four during a rainstorm, especially after a dry spell. The
• 2:48
  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
• 2:55
  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
• 3:00
  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,
• 3:10
  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.
• 3:22
  Speaker 1: Were smelling. It's this molecule that stripped of mices produces
• 3:26
  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
• 3:33
  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
• 3:46
  Speaker 1: Bear and Thomas, and they didn't know exactly how that
• 3:50
  Speaker 1: would happen though, like how does a molecule in the
• 3:53
  Speaker 1: soil get into the air to make it, you know,
• 3:56
  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
• 4:01
  Speaker 1: two thousand and fifteen, that it becomes aerosolized. Yeah, that's
• 4:04
  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
• 4:19
  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
• 4:26
  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
• 4:37
  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,
• 4:49
  Speaker 1: it pops through the rain drops into the air, and
• 4:51
  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
• 4:58
  Speaker 1: before the storm. It's smells just at the very beginning
• 5:03
  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
• 5:45
  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
• 6:09
  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
• 6:15
  Speaker 1: it a mile away. That's all internet legend. Okay, sure,
• 6:18
  Speaker 1: but even still, I mean, the shark smells blood to
• 6:21
  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
• 6:31
  Speaker 1: a riddle there. There's a red flag evolutionarily speaking, that
• 6:35
  Speaker 1: we have yet to figure out. But it definitely is significant.
• 6:39
  Speaker 1: All Right, We're going to spend sixty seconds trying to
• 6:41
  Speaker 1: figure it out. You listen to this break and we'll
• 6:45
  Speaker 1: come back and figure it out and let you know. Alright,
• 7:07
  Speaker 1: so here's another cool thing the paper. But did we
• 7:10
  Speaker 1: figure it out? Now? We didn't figure it out. Okay,
• 7:14
  Speaker 1: here's the thing in that paper by Baron Thomas in
• 7:16
  Speaker 1: n s four. It's pretty cool. Uh. They found out
• 7:21
  Speaker 1: that this the scent was being captured and sold in
• 7:26
  Speaker 1: India as mettica atar and Geosman is also like becoming
• 7:31
  Speaker 1: a perfume ingredient, which is pretty amazing. Yeah, it has
• 7:34
  Speaker 1: been in India for a while, but the uh, I
• 7:36
  Speaker 1: guess the perfume industry in the United States and Europe
• 7:39
  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
• 7:44
  Speaker 1: as they say, yes, because Geosman also appears um in
• 7:49
  Speaker 1: other places, sometimes in the ter war of wine or
• 7:53
  Speaker 1: in mineral water. I don't know that, however, detected it
• 7:56
  Speaker 1: at least they didn't realize that. Yeah. I need to
• 7:59
  Speaker 1: know what it it is because I love beats, I
• 8:01
  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
• 8:09
  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
• 8:13
  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
• 8:20
  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,
• 8:27
  Speaker 1: I would hate it immediately and possibly forever. So I
• 8:30
  Speaker 1: just think about other stuff, like you know, baseball or
• 8:34
  Speaker 1: my old cabbage patch kid when I was younger. Interesting. Yeah,
• 8:38
  Speaker 1: I don't know about the second one, but yes, okay,
• 8:41
  Speaker 1: but that's not all, is it, Chuck. No, This this
• 8:43
  Speaker 1: next part is really cool to me, um, because if
• 8:47
  Speaker 1: you've ever noticed, if you've been in a rainstorm in
• 8:49
  Speaker 1: the country or the woods, it smells very different than
• 8:52
  Speaker 1: in the city. And that's not just because when it
• 8:56
  Speaker 1: rains in the city it's kicking up pee and poop
• 8:58
  Speaker 1: and garbage and stuff like that into the here. No,
• 9:00
  Speaker 1: because it's something. It technically smells cleaner in the city
• 9:04
  Speaker 1: than it does even in the countryside. Yeah, and that's
• 9:06
  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
• 9:13
  Speaker 1: is ozone, that third ingredient that you smell when you
• 9:18
  Speaker 1: have that patricor effect? Is that a term? The the
• 9:23
  Speaker 1: effect of it effect up, Yeah, is lightning. So when
• 9:28
  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
• 9:35
  Speaker 1: put your finger on is ozone, Yeah, which is produced
• 9:38
  Speaker 1: naturally up in the atmosphere. But the electrical like bolt
• 9:43
  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
• 9:52
  Speaker 1: specific smell. It's weird. It's a weird smell. I remember
• 9:56
  Speaker 1: we had a listener one time that was, um, do
• 9:58
  Speaker 1: you remember this guy he was making O owned deodorant. No, yeah,
• 10:02
  Speaker 1: he sents. I think he sent it to me because
• 10:04
  Speaker 1: he knows that I have deodorant problems. Oh I want
• 10:06
  Speaker 1: to try that. Who if you're listening please years ago.
• 10:10
  Speaker 1: But if you're listening citizen some more. I didn't care
• 10:12
  Speaker 1: for it. Had a weird smell, and he was like, yeah,
• 10:15
  Speaker 1: some people ozone's kind of goes one way or the other.
• 10:18
  Speaker 1: I'll use your old stick if you're not using it anymore.
• 10:20
  Speaker 1: I don't think you want my four year old ozone
• 10:23
  Speaker 1: deodan Yeah, yeah, with like your armpit hair is still
• 10:26
  Speaker 1: stuck to the top of it. Oh gosh. Um. So
• 10:29
  Speaker 1: the reason why it smells cleaner in the city is
• 10:32
  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
• 10:43
  Speaker 1: the countryside, which means you get more of an ozone
• 10:46
  Speaker 1: smell in the city, which means it smells cleaner in
• 10:48
  Speaker 1: the city. Yeah, it's not like there's more ozone in
• 10:50
  Speaker 1: the city, is just more prominent because there's less of
• 10:53
  Speaker 1: the geosman, right, right, But there is another ingredient and
• 10:57
  Speaker 1: we skipped over it's technically the second ingredient. And they're
• 11:00
  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
• 11:13
  Speaker 1: distinctive smells. They think that tirpenes are activated through a
• 11:17
  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
• 11:24
  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,
• 11:30
  Speaker 1: that rain may be hard enough to where it like
• 11:33
  Speaker 1: breaks off dry plant material and stuff like that releases
• 11:36
  Speaker 1: that chemical uh, and they like in it. In this
• 11:38
  Speaker 1: article from the BBC, just like when you crush up
• 11:41
  Speaker 1: dried herbs, it releases that smell. Yeah, and it would
• 11:44
  Speaker 1: probably follow the same process as the geosman where it
• 11:48
  Speaker 1: just becomes airsolized by the raindrops as they hit them.
• 11:51
  Speaker 1: Very cool. This is a good one to know. Like,
• 11:53
  Speaker 1: next time you're in a rainstorm and someone comments about
• 11:56
  Speaker 1: why it smells, just say patricor or the next time
• 12:00
  Speaker 1: was somebody just spits out a bite full of food
• 12:02
  Speaker 1: in their napkin and says, I hate beats. You can
• 12:05
  Speaker 1: explain what petricor right, Well, that's it for petrocor, patricor
• 12:12
  Speaker 1: whatever you want to call it. Uh, it has been done.
• 12:15
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