It starts with this guy Clair Patterson in a lab trying to figure out the age of the earth by dating a meteorite. The first thing he has to do is calculate the amount of lead in the meteorite — except his readings are way off. He realizes he has to control for that variable by determining the amount of lead in the lab.
———————
from the episode transcript:
LYDIA DENWORTH: So first he started with glass beakers he was using.
AVIR: The vials are the first thing you’re gonna look at. So he tests the vials. And he goes, “Shit.”
[ARCHIVE CLIP, Clair Patterson: Lead.]
AVIR: These glass vials are made with lead, so let’s get some new vials.
LATIF: Right.
AVIR: So gets new glass vials. Special order, never made with lead. Runs a sample again. It’s still off.
LATIF: Huh.
AVIR: And so then he’s like, “You know what? In the sample where I put the granite, I also put some water in it.” And he realizes, actually, the water is coming from lead pipes.
LATIF: Ah.
AVIR: And so he’s like, “Oh, crap. That’s the problem.” So he has to triple distill the water, boil it off, make sure he catches it in a vial that has no lead in it, to make sure that his water doesn’t have any contamination from the pipes it came through. So he runs the sample and it’s a little better, but there’s still lead there. So now he’s, like, obsessed. And Patterson, he’s working in this lab.
LYDIA DENWORTH: And it was pretty grubby.
AVIR: He looks at the walls and he’s like …
LYDIA DENWORTH: There is peeling paint.
AVIR: So he tests the paint.
LYDIA DENWORTH: It was in the paint.
AVIR: So they repaint the walls. But still …
LYDIA DENWORTH: There was way too much lead.
AVIR: Then he looks at his desk where the mass spectrometer is sitting on, and he figures out every joint in the desk is soldered together with lead.
LATIF: Oh, man.
AVIR: So he needs a new desk, new chairs with no lead. And then he uses Saran Wrap to cover every desk and every chair and every object in the room.
LATIF: [laughs].
AVIR: And still, too much lead.
LATIF: Wow!
AVIR: And so he thinks maybe there’s some lead in the dust on the floors. So he starts mopping the floors. He gets the lead numbers to come down a little bit. And then one day, he notices a co-worker’s lipstick is messing up his samples.
LATIF: Hmm.
AVIR: So he tests the makeup and he’s like, “Okay, there’s lead in there too.
LATIF: Wow.
AVIR: We can’t wear makeup in this lab. And he eventually—he starts to get the lead number lower and lower. But then one day, he’s working in the lab, and a little piece of his hair falls onto the desk, and the lead numbers shoot up.
LYDIA DENWORTH: He said, you know, “Holy shit!”
[ARCHIVE CLIP, Clair Patterson: Your hair!]
LYDIA DENWORTH: It’s on him.
LATIF: [gasps] Wow! He’s the contamination himself!
[ARCHIVE CLIP, Clair Patterson: The lead from your hair will contaminate the whole damn laboratory. Just from your hair. [laughs]]
AVIR: And so he shaves his head.
LATIF: [laughs]
AVIR: But then one day he decides, “Okay, well I’m just gonna test my skin.” And he ends up seeing that there’s a bunch of lead in his skin.
LATIF: Oh, no!
AVIR: It’s everywhere.
LYDIA DENWORTH: There was lead in absolutely everything. And in the end, he made people—they had a little anteroom and you had to—you literally had to strip down to your underwear and put on this Tyvek suit.
AVIR: Which gets washed in acid.
LYDIA DENWORTH: And have little booties on and put plastic over their hair.
AVIR: He builds positive pressure air vents so the air is constantly blowing and pushing anything inside the lab outside of the lab. So even if you walk in with a little microgram of lead, the air may push it out.
LATIF: Hmm.
AVIR: He basically invents what we now call a “clean lab.”
LATIF: Hmm.
AVIR: But he ultimately gets his samples down, his blank samples down to 0.1 micrograms. So that’s one tenth of one millionth of a gram.
LATIF: Oof!
AVIR: And that took years.
——————
So this is something like: repeated experiments to isolate the variables that matter in one context only to make a scientific discovery in another context.
This reminded me of the story of how we got unleaded gasoline as described in a recent RadioLab episode titled, “Heavy Metal.” https://www.wnycstudios.org/podcasts/radiolab/articles/heavy-metal
It starts with this guy Clair Patterson in a lab trying to figure out the age of the earth by dating a meteorite. The first thing he has to do is calculate the amount of lead in the meteorite — except his readings are way off. He realizes he has to control for that variable by determining the amount of lead in the lab.
———————
from the episode transcript:
LYDIA DENWORTH: So first he started with glass beakers he was using.
AVIR: The vials are the first thing you’re gonna look at. So he tests the vials. And he goes, “Shit.”
[ARCHIVE CLIP, Clair Patterson: Lead.]
AVIR: These glass vials are made with lead, so let’s get some new vials.
LATIF: Right.
AVIR: So gets new glass vials. Special order, never made with lead. Runs a sample again. It’s still off.
LATIF: Huh.
AVIR: And so then he’s like, “You know what? In the sample where I put the granite, I also put some water in it.” And he realizes, actually, the water is coming from lead pipes.
LATIF: Ah.
AVIR: And so he’s like, “Oh, crap. That’s the problem.” So he has to triple distill the water, boil it off, make sure he catches it in a vial that has no lead in it, to make sure that his water doesn’t have any contamination from the pipes it came through. So he runs the sample and it’s a little better, but there’s still lead there. So now he’s, like, obsessed. And Patterson, he’s working in this lab.
LYDIA DENWORTH: And it was pretty grubby.
AVIR: He looks at the walls and he’s like …
LYDIA DENWORTH: There is peeling paint.
AVIR: So he tests the paint.
LYDIA DENWORTH: It was in the paint.
AVIR: So they repaint the walls. But still …
LYDIA DENWORTH: There was way too much lead.
AVIR: Then he looks at his desk where the mass spectrometer is sitting on, and he figures out every joint in the desk is soldered together with lead.
LATIF: Oh, man.
AVIR: So he needs a new desk, new chairs with no lead. And then he uses Saran Wrap to cover every desk and every chair and every object in the room.
LATIF: [laughs].
AVIR: And still, too much lead.
LATIF: Wow!
AVIR: And so he thinks maybe there’s some lead in the dust on the floors. So he starts mopping the floors. He gets the lead numbers to come down a little bit. And then one day, he notices a co-worker’s lipstick is messing up his samples.
LATIF: Hmm.
AVIR: So he tests the makeup and he’s like, “Okay, there’s lead in there too.
LATIF: Wow.
AVIR: We can’t wear makeup in this lab. And he eventually—he starts to get the lead number lower and lower. But then one day, he’s working in the lab, and a little piece of his hair falls onto the desk, and the lead numbers shoot up.
LYDIA DENWORTH: He said, you know, “Holy shit!”
[ARCHIVE CLIP, Clair Patterson: Your hair!]
LYDIA DENWORTH: It’s on him.
LATIF: [gasps] Wow! He’s the contamination himself!
[ARCHIVE CLIP, Clair Patterson: The lead from your hair will contaminate the whole damn laboratory. Just from your hair. [laughs]]
AVIR: And so he shaves his head.
LATIF: [laughs]
AVIR: But then one day he decides, “Okay, well I’m just gonna test my skin.” And he ends up seeing that there’s a bunch of lead in his skin.
LATIF: Oh, no!
AVIR: It’s everywhere.
LYDIA DENWORTH: There was lead in absolutely everything. And in the end, he made people—they had a little anteroom and you had to—you literally had to strip down to your underwear and put on this Tyvek suit.
AVIR: Which gets washed in acid.
LYDIA DENWORTH: And have little booties on and put plastic over their hair.
AVIR: He builds positive pressure air vents so the air is constantly blowing and pushing anything inside the lab outside of the lab. So even if you walk in with a little microgram of lead, the air may push it out.
LATIF: Hmm.
AVIR: He basically invents what we now call a “clean lab.”
LATIF: Hmm.
AVIR: But he ultimately gets his samples down, his blank samples down to 0.1 micrograms. So that’s one tenth of one millionth of a gram.
LATIF: Oof!
AVIR: And that took years.
——————
So this is something like: repeated experiments to isolate the variables that matter in one context only to make a scientific discovery in another context.