Polymetalic Nodules Are Weird

Summary

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Podcast Summary: The Rest Is Science

Episode: "Polymetallic Nodules Are Weird"

Original Air Date: May 13, 2026
Hosts: Professor Hannah Fry & Michael Stevens (Vsauce)

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Overview

In this engaging episode of The Rest Is Science, Professor Hannah Fry and Michael Stevens unravel the strangeness and unexpected significance of polymetallic nodules—potato-sized lumps rich in metals, found on the deep ocean floor. Blending quirky anecdotes, personal experiments, and cutting-edge science, the hosts journey from Cold War-era cloak-and-dagger operations to the paradoxes of green technology, all while fielding listener questions about handedness, lightning strikes, and the physics of humidity.

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Key Discussion Points & Insights

1. The Glomar Explorer and Ocean Mystery (00:04–01:46)

• Origin Story: Hannah recounts how Howard Hughes and the CIA used a cover story about mining odd ocean rocks—the mysterious Glomar Explorer mission—to disguise efforts to salvage a sunken Soviet submarine.
• Quote:

  “It was actually this massive stunt that the CIA were doing... He [Hughes] was just a cover. It wasn’t his ship.”
  – Hannah Fry (01:04)

2. Introducing the Polymetallic Nodule (03:52–05:17)

• Personal Artifact: Hannah presents her prized polymetallic nodule, encased in a pendant, describing its Atlantic origins, chalky feel, and the sense of guilt for not knowing the anonymous gift-giver’s identity.
• Sensory Exploration: Michael examines, smells, and even licks the nodule for science.

  “Can I lick it?”
  – Michael Stevens (05:26)
  “I probably should have risk assessed the idea of you licking a polymetallic nodule.”
  – Hannah Fry (06:05)

3. How Nodules Form & Their Geological Story (06:12–08:14)

• Formation Process:
  • Begin with a “seed” (shark/mammoth tooth, meteorite) that sinks, accumulates metal layers over millions of years, primarily through underwater volcanic activity and mineral-rich waters.
  • Growth rate: 1 millimeter every million years.
  • Nodules reach potato-to-grapefruit size; original seeds may date to the dinosaur era.
• Quote:

  “This is one of the slowest geological processes on the entire planet.”
  – Hannah Fry (07:29)

4. Chemistry, Physics & Environmental Dilemmas (08:14–10:31)

• Formation Mechanism:

  • “Hydrogenous precipitation”—minerals bond to the nodule’s surface as it’s exposed to seawater.
  • Nodules act like "natural batteries," with clusters potentially generating voltages up to two volts, aiding in seabed oxygenation.

• Modern Relevance:

  • Nodules contain high concentrations of metals essential for electric car batteries—nickel, cobalt, manganese. Surface deposits have dwindled, raising questions about deep-sea mining’s ecological impacts.
  • Ethical Paradox:

    "To make cars greener, maybe we should do this really quite environmentally damaging thing, which is going back... to Howard Hughes’s idea."
    – Hannah Fry (09:54)

• Comic Relief & Concerns:

  • Michael jokes about leaving trash in exchange for nodules.

    “We’ll leave some trash down there in its place... Like here’s a bunch of straws.”
    – Michael Stevens (10:28)

5. Listener Q&A Segment

a. Can We Train Ambidexterity? (14:30–20:00)

• Scientific Uncertainty:
  • “Handedness” origins remain mysterious; ~10% are left-handed, only ~1% ambidextrous.
• Practical Observations:
  • The dominant hand specializes; the other supports coordination—“a great team.”
• Brain Health Hypothesis:
  • Training non-dominant skills may support brain health and delay dementia due to increased “cross-wiring.”
• Fun Fact:

  “The opposite of ambidextrous is ‘ambisinister’—not good with either hand.”
  – Michael Stevens (17:31)

b. Strange Neurology—Left Neglect (18:06–19:58)

• Left Neglect Phenomenon:
  • Brain injury on the right hemisphere can cause patients to ignore the left side of space.
  • Observed more in right-handers and sometimes appears transiently in sleep-deprived doctors.

c. Do Taller Animals Get Struck by Lightning More? (21:04–23:38)

• Surprising Danger:

  • Giraffes and tall animals are more likely to be directly struck due to height.
  • Step Voltage:
    • Most animal deaths are from ground current “step voltage” following a nearby strike.

  “This ground current effect can just take out an entire herd at the same time.”
  – Hannah Fry (23:22)

• Safety Insight:

  • If caught in a storm: keep feet together to avoid being a bridge for current.

d. Cold & Humid vs. Cold & Dry—Is Damp Cold Worse? (25:26–29:55)

• Physics of Humidity:

  • Humid air makes cold feel colder and heat feel hotter (water conducts heat away faster).
  • Humans sense temperature differences, not true wetness.

• Counterintuitive Fact:

  • Humid air is actually less dense than dry air.

  "Water vapor is replacing molecules that are much heavier... humid air is a lot less dense."
  – Michael Stevens (27:59)

  • Anecdote on a baseball team manipulating stadium humidity to impact game physics.

• Misconceptions:

  • Clouds = tiny liquid drops, not water vapor; vapor is invisible.

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Memorable Moments & Quotes

• Michael’s Experiment:

  “I’m gonna stretch it like I’m breaking an egg open... Can I lick it?”
  (05:03, 05:26)

• On Nodule Formation:

  “It's like a pearl forming in an oyster, except the oyster is the entire ocean.”
  – Michael Stevens (08:31)

• Environmental Irony:

  “To make cars greener, maybe we should do this really quite environmentally damaging thing...”
  – Hannah Fry (09:54)

• Left Neglect Anecdote:

  “They as a result just don’t pay attention to anything on the left hand side...”
  – Hannah Fry (18:23)

• Lightning Step Voltage:

  “Their bodies were the shortest path between the two.”
  – Hannah Fry (23:33)

• Humid Air Density:

  “Humid air is a lot less dense. Even though it feels like oppressively dense, it’s not.”
  – Michael Stevens (27:59)

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Fun & Lighthearted Tangents

• Accent Debate & Impressions:
  • Playful discussion and impersonation attempts of Kiwi and British accents, sparked by a poll ranking New Zealand as the “sexiest accent” (30:34–32:20).
• Quotes:

  “I think that was undeniably sexy.”
  – Unidentified Additional Participant (32:07)

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Timestamps for Major Segments

• Glomar Explorer CIA Story: 00:04–01:46
• Introduction to Nodules (Object Unveiling & Experiment): 03:52–06:13
• Geology and Chemistry of Nodules: 06:13–10:31
• Deepsea Mining Ethics & Future: 09:14–10:31
• Listener Question: Ambidexterity & Brain Health: 14:30–20:00
• Listener Question: Left Neglect: 18:06–19:58
• Lightning & Tall Animals: 21:04–23:38
• Humidity, Cold, and Physics: 25:26–30:19
• Accents Banter & Impressions: 30:34–32:20

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Takeaways

• Polymetallic nodules are ancient, slow-forming metal-rich rocks that have both natural wonder and technological value—posing new ethical questions as we mine for green tech.
• Our everyday assumptions about the ocean, brain wiring, weather, and even accents often hide deeper scientific mysteries.
• The episode blends curiosity, scientific storytelling, and humor—plus a bit of reckless licking in the cause of podcast science.

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For more weird wonders, listener questions, or to suggest topics, contact the show at: [e-mail]

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Transcript

[Hannah Fry]

Welcome to the rest of science. I'm Hannah Fry.

[Michael Stevens]

And I'm Michael Stevens.

[Hannah Fry]

And we're doing field notes today, which is where one of us brings a little object. My object starts with a story. Have you heard about that Howard Hughes, the eccentric billionaire?

[Michael Stevens]

I've heard of him. Yeah.

[Hannah Fry]

You've heard of him. He comes up, you know, in the middle of the Cold War, he built this massive ship. Do you know this story?

[Michael Stevens]

Like a ship that floated?

[Hannah Fry]

A ship that floated.

[Michael Stevens]

No, I knew more about his airplanes.

[Hannah Fry]

Okay. It's called the Glomar Explorer.

[Michael Stevens]

Oh.

[Hannah Fry]

And he did this big announcement to the whole world, and he said that he was gonna go out on the ocean and he was gonna mine these worthless looking black rocks at the bottom of the Pacific Ocean.

[Michael Stevens]

For what? For iron, nickel, gold, whatever. For whatever.

[Hannah Fry]

For whatever. Okay. Just about plausible enough to seem true.

[Michael Stevens]

Yeah.

[Hannah Fry]

It was actually this massive stunt that the CIA were doing. What he was actually doing. Do you know about this?

[Michael Stevens]

Wait, I remember this story vaguely. Let me guess. When what he was actually doing was. No, I don't. Tell me.

[Hannah Fry]

He had nothing to do with it at all, really. He was just a cover. It wasn't his ship.

[Michael Stevens]

The CIA was doing something.

[Hannah Fry]

Yes. The CIA wanted to steal a sunken

[Michael Stevens]

Soviet submarine for its technology.

[Hannah Fry]

Yeah. Work out what they were doing on there. So they needed to send over this massive ship that was gonna go down to the bottom of the ocean. But they needed this cover story. And they were like, how are Hughes? And, you know, this whole, like, oh, yeah, rocks at the bottom of the oce. And it worked. It was this really great piece of theater. This episode is brought to you by Cancer Research uk.

[Michael Stevens]

Here's something strange. Your DNA contains more ancient viral fragments than genes. The genes that build our cells make up only 2% of our DNA. And for years, that is what scientists focused on. They treated the. The ancient viruses and stuff as junk.

[Hannah Fry]

But now we know that that hidden majority, sometimes called the dark genome, influences how our biology works and how diseases like cancer behave.

[Michael Stevens]

It's a reminder that progress rarely comes as a single breakthrough. It builds gradually. Cancer Research UK plays a central role in that progress, supporting decades of research into over 200 types of cancer, work that's helped double survival in the UK over the past 50 years.

[Hannah Fry]

For more information about Cancer Research UK, their research breakthroughs, and how you can support them, visit cancerresearchuk.org thereestiscience.

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[Unidentified Carvana Customer Friend]

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[Unidentified Carvana Customer]

No, you don't understand. It went perfectly real Offer down to the penny. They're picking it up tomorrow. Nothing went wrong.

[Unidentified Carvana Customer Friend]

So what's the problem?

[Unidentified Carvana Customer]

That is the problem. Nothing in my life goes as smoothly. I'm waiting for the catch.

[Unidentified Carvana Customer Friend]

Maybe there's no catch.

[Unidentified Carvana Customer]

That's exactly what a catch would want me to think.

[Unidentified Additional Participant]

Wow.

[Unidentified Carvana Customer Friend]

You need to relax.

[Unidentified Carvana Customer]

I need a knock on wood. Do we have wood? Is this table wood?

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[Unidentified Carvana Customer Friend]

Car selling without a catch.

[Michael Stevens]

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[Michael Stevens]

Describe bottom of the ocean. Like, how deep.

[Hannah Fry]

Oh, I'm talking bottom, bottom, bottom of the ocean.

[Michael Stevens]

That's cool.

[Hannah Fry]

Okay, now I have to tell you first before you. Before I hand this to you. This is now, I think one of my prized possessions, but I feel very guilty because somebody, I don't know who, sent this to me as a gift to my Cambridge office. Okay. And they had a really lovely letter in there, and there was a map from exactly where it was recovered from what part of the ocean. And I can't find the letter anywhere. I can only find this.

[Michael Stevens]

Do you remember if it was the Atlantic or the Pacific?

[Hannah Fry]

It was the Atlantic. It was the Atlantic.

[Michael Stevens]

Okay.

[Hannah Fry]

So anyway, whoever it was that sent me this, I'm really, really, really grateful. But this is what is known as a polymetallic nodule. It's in a little necklace thing, but you can pull it out if you want to. Okay.

[Michael Stevens]

Oh, right.

[Hannah Fry]

I promise. These are exciting. I promise. Okay.

[Michael Stevens]

So it's inside a pendant on a string necklace. And the rock is black. It's about the size of a. A die, and it is black.

[Hannah Fry]

Pull it out.

[Michael Stevens]

I can pull it out. So the pendant that it's inside is a wire that's coiled up into a big helix egg shape. And it's like a copperish brass wire. So I'm gonna. How do I get it? I don't wanna stretch this.

[Hannah Fry]

Yeah, yeah, go. And you can stretch it.

[Michael Stevens]

You can stretch it. I'm stretch it like I'm breaking an egg open. And I'm gonna get the rock out. This is a Great way to hold the rock. Cause it won't fall out in normal use. But it does come out. Polymetallic nodule.

[Hannah Fry]

Yes.

[Michael Stevens]

So it has many different metals in it.

[Hannah Fry]

Yes. And it feels really metallic.

[Michael Stevens]

I gotta smell it. I don't know, I. It's got almost a chalky texture.

[Hannah Fry]

It does, it does, it does.

[Michael Stevens]

Can I lick it?

[Hannah Fry]

Yeah, go on.

[Unidentified Additional Participant]

What's gonna happen?

[Hannah Fry]

Oh, no, wait.

[Unidentified Additional Participant]

No, wait.

[Hannah Fry]

No, I'm joking.

[Michael Stevens]

It's really dry.

[Unidentified Additional Participant]

Is it?

[Michael Stevens]

It's like, drier than I would expect most rocks to be. I think it's a little porous. Is it volcanic?

[Hannah Fry]

No, it is not volcanic.

[Michael Stevens]

Look, it's leaving dust on my fingers.

[Hannah Fry]

Yeah.

[Michael Stevens]

And now I know I'm gonna clean my tongue.

[Unidentified Additional Participant]

I'm sorry.

[Michael Stevens]

Because of what? There's probably lead in it.

[Unidentified Additional Participant]

Oh, God.

[Michael Stevens]

Hold on. Anyway, I did it for you all.

[Unidentified Additional Participant]

I hope there's not lead in it.

[Michael Stevens]

It's not very dense.

[Unidentified Additional Participant]

No.

[Michael Stevens]

I'm making it sound like it's made out of polystyrene, but no, it's definitely a rock. I'm just gonna do a quick little mouthwash.

[Unidentified Additional Participant]

I probably should have risk assessed the idea of you licking a polymetallic nodule before I suggested you do it.

[Michael Stevens]

Better me than like my child.

[Hannah Fry]

I agree. Okay.

[Unidentified Additional Participant]

I'm sure you'll be fine.

[Hannah Fry]

Okay.

[Michael Stevens]

I mean, surely the ocean washed it.

[Hannah Fry]

Surely the ocean washed it. Okay, so, right. The thing about these rocks, okay, they

[Unidentified Additional Participant]

have the most unreal history, present and future, right. As three separate entities.

[Hannah Fry]

So the way that they're created, these rocks, I mean, why are you getting rocks at the bottom of the ocean? Surely it's all sand, right? It doesn't make any sense that you would have these rocks. But what happens is that a tiny bit of debris, right? And it's things like a shark tooth, or even longer ago, maybe a Megalodon tooth or a little bit of a meteorite, something like that floats down in the ocean and then settles in the mud right at the bottom. And then they begin their life like this. But over millions and millions of years. Think you've got all of these underwater volcanoes. So they're spewing out this very sort of metallic rich debris all across the place. And over millions of years, manganese, nickel, cobalt, they slowly come out of the seawater and end up bonding to this original seed, this original piece of debris. And this is, by the way, one of the slowest geological processes on the entire planet. They accumulate at about 1 millimeter every million years. Wow.

[Michael Stevens]

Right.

[Hannah Fry]

It's unbelievably slow. When you find them, they're roughly the size of a potato or a grapefruit maybe.

[Michael Stevens]

Really?

[Hannah Fry]

They're like these unbelievable pearls, you know, with this like incredibly interesting center and then extremely rich surrounding. So the fact that they're so old, you know, you have to. That was probably the original seed for that was probably around the time of the dinosaurs. Yeah. Okay, that's. That's what we're talking about. These grapefruits that are sitting at the bottom of the ocean that have been there since the time of the dinosaurs. But because they have so much metal in them, no lead, thankfully.

[Unidentified Additional Participant]

We hope.

[Michael Stevens]

Is that confirmed?

[Hannah Fry]

Let's check.

[Michael Stevens]

Just pretend to check and then tell me that it's fine. What is this process of rock formation called?

[Hannah Fry]

Okay. It's called hydrogenous precipitation. So the idea is that the top half of the nodule is kind of exposed to the seawater and then it just absorbs all of these dissolved metals as they float past.

[Michael Stevens]

And what do they attract more? Yes. So it really is like a pearl forming in an oyster.

[Hannah Fry]

Yes, it really is.

[Michael Stevens]

Except the oyster is the entire ocean.

[Hannah Fry]

Uh huh. Exactly.

[Michael Stevens]

Wow.

[Hannah Fry]

So the other thing about these is that they essentially act as natural batteries because they've got these really tightly layered metallic isotopes. They have this naturally occurring electrical charge in them. And when you get loads of them together and you do, you get sort of. Because of course, a millions of years you get them when you have thousands of them that are clustered together, the combined voltage can actually be like a volt, two volts or so, which means that you can split seawater into hydrogen and oxygen and it oxygenates the bottom. The ocean.

[Unidentified Additional Participant]

Yeah.

[Hannah Fry]

I mean, that's cool.

[Michael Stevens]

Oh my gosh.

[Hannah Fry]

That's fun, isn't it?

[Michael Stevens]

You're welcome, fish.

[Hannah Fry]

You're welcome, fish. Enjoy. But the thing about them that in terms of their future is that all of the metals that are in here, which are extremely rare once you come up to the surface of the earth, but you find them in this incredible concentration within these nodules are exactly the same metals that you need to make. For example, electric cars. Right. Batteries and electric cars. So there is this kind of paradox that's going on at the moment, which is that to make cars greener, maybe we should do this really quite environmentally damaging thing which is going back.

[Michael Stevens]

I'm sorry, I thought you were going to say we should do this as an episode.

[Unidentified Additional Participant]

No, say that again. No, maybe we should.

[Michael Stevens]

Maybe they're really damaging. I'm like, we should.

[Unidentified Additional Participant]

Well, I don't know.

[Hannah Fry]

It goes back to Howard Hughes's idea. Maybe we should really do the Howard Hughes thing.

[Michael Stevens]

Well, yeah. Especially if metals and especially rare metals are congregating together because it's easier for them to move through water. We're never going to find nodules that form in that way in dirt.

[Hannah Fry]

No.

[Michael Stevens]

So mining, especially rare earth minerals, is a very intensive process. But the oceans already allowed time to collect them together.

[Hannah Fry]

Yeah. Although I think it probably would be quite disruptive to marine life if we went down there and got them. But there's, like, a lot of them. There's a lot. I mean, the ocean can spare some.

[Michael Stevens]

The ocean. We can just borrow some.

[Hannah Fry]

Yeah, exactly.

[Michael Stevens]

We'll leave some trash down there in its place. They'll pull an Indiana Jones like and here's a bunch of straws.

[Unidentified Additional Participant]

Yeah.

[Hannah Fry]

You know, I sort of feel like I should lick it as well, so

[Unidentified Additional Participant]

that at least if you die, I die as well.

[Michael Stevens]

I think it's one of those things that'll just slowly kill me or it'll lead to faster cognitive decline in decades to come.

[Hannah Fry]

Look, you mess around with yellow cake, all right.

[Unidentified Additional Participant]

This is licking a bit of rock

[Michael Stevens]

is the yellow cake. Okay.

[Unidentified Additional Participant]

Should we do some questions?

[Michael Stevens]

Let's do some questions, yeah.

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[Hannah Fry]

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[Michael Stevens]

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[Michael Stevens]

So this question comes from Mike. Mike asks, can we train ourselves to be ambidextrous? I learned to shoot a basketball with both hands but I feel like my non dominant hand left will never be as good as my dominant right one. Well you can, you can definitely train yourself to be ambidextrous. In fact, many left handed people were forced to do this and to this day still train themselves away from it. It takes time, but handedness is a pretty big mystery. Still, we have some evidence of handedness in in non human animals, but it's not nearly as strong as it is in humans. And so the origins of handedness are kind of unknown. About 10% of people are left handed. Only about 1% of people are ambidextrous. Like truly, they can do fine and gross motor skills equally well with both hands. I think the less dominant hand gets a bad rap though because maybe it's not good at certain fine motor skills, but it is a fantastic helper and follower. Like if you try to write on a sheet of paper with your non dominant hand, which in my case is the left, not only does it have trouble forming the little letters, but my right hand has no idea what to do. I'm like where do I Put it. It's supposed to be holding the paper or moving it and I can't do it. But my left hand instinctively just is like, yep, here's where I'm gonna be the dominant guy, the dominant. And when it comes to throwing a ball, the left hand, in my case again, the non dominant hand does a lot of work in terms of balance. And I find that when I throw with my dominant hand, my left hand knows exactly where to be to balance everything out and give me really great leverage. When I throw with my left, my right arm is like, hey, I'm in the way. I don't know how to, how to work them together. So really they're like this great team. It's like a little Abbott and Costello, a little hall and Oates, a little Simon and Garfunkel, a little peanut butter and jelly, a little, okay, I ran out of famous pears off the top of my head. But yeah, you can train yourself and it's worth doing as a party trick. But otherwise, I don't know, it's fine to just have a dominant and a non dominant.

[Hannah Fry]

I do wonder though whether it is better for your brain because of course your brain is sort of cross wired, right? Like the right hand side of your brain controls the left hand side of your body and vice versa. So I wonder about, I'm thinking about dementia here. I wonder whether if you train yourself to become ambidextrous, whether you're, I mean, in general, the more that you do to support your brain to push it in directions that it doesn't feel comfortable in, the better that you can stave off dementia.

[Michael Stevens]

I wonder, it could be good for your brain health because it's certainly a cognitive exercise of a unique kind. Could you train yourself to be the opposite of ambidextrous? Could you train yourself to be amba Sinister? That's what it's called when you're not good with either of your hands.

[Hannah Fry]

Right?

[Michael Stevens]

Yeah, it's not a real thing, but yes, sinister means left and dexterous meant right.

[Hannah Fry]

So is that a Google whack, Amber? Sinister?

[Michael Stevens]

I don't think so, but look it up. But yes, sinister meaning left shows you historically how we have treated left handed people.

[Hannah Fry]

It is. It's a real word.

[Michael Stevens]

It's a real. Would I lie? I thought you. I on this podcast.

[Hannah Fry]

Sorry, I thought. Yes, I thought you did.

[Michael Stevens]

Well, I mean, did you think that I made it up though? It was. Would technically be like a word for it. Yeah, but it is a real thing.

[Hannah Fry]

I did a program once on on left handedness. And I spoke to this neuroscientist called Sophie Scott, who's absolutely amazing, like really brilliant science communicator as well as a scientist. Anyway, she told me this incredible story about something called left neglect. Have you come across this?

[Michael Stevens]

No.

[Hannah Fry]

So it's this really strange phenomenon where somebody gets a brain injury to the right hand side of their head. Okay. To the right hemisphere, and then they as a result just don't pay attention to essentially anything on the left hand

[Michael Stevens]

side in the visual field even.

[Hannah Fry]

Yeah. And it's not that they can't see it because if they are, if they are told to look at it, then they see it, but they just don't pay attention to it. So for example, you get people who have left neglect shaving half of their face if eating half a plate of food, not noticing it. I have a feeling that Dickens had this actually. Or there was someone who, some famous writer who had it and then talks about just not noticing that lamp posts sort of appearing on the left hand side. Anyway, Sophie was telling me about this study they were doing in, in hospitals in Manchester where they were following doctors who had been on extremely long shifts. Okay. So I'm talking about serious sleep deprivation under these conditions. You also see signs of left neglect in these doctors or. But only if they are right handed.

[Michael Stevens]

Oh, what if they're left handed?

[Hannah Fry]

So you don't see it. You don't see it. You see sometimes flickers of right neglect, but it's way more transient.

[Michael Stevens]

Oh, strange.

[Hannah Fry]

And I think there's some idea that you have this sort of resistance to these severe spatial biases because your, your, your attention network is better distributed across the whole of your brain rather than just on one side. But it's like. Yeah, I mean, active areas of research.

[Michael Stevens]

Well, you got to give those researchers a hand.

[Hannah Fry]

Which one?

[Michael Stevens]

But which one? We should also look more into the origin of handedness because until that question from Mike, I thought we knew what caused it and what the advantages were. And I thought that it was widespread in the animal kingdom. But one thing is it's hard to find the origin because although we have pretty good evidence that Neanderthals exhibited handedness, that'll come from things like how did they sharpen tools and how did they hold something down while they worked on it. There's a way to figure it out. I know that with early humans we find a lot of handprints, right. Where someone put their hand on a rock and then they sprayed the pigment on it to leave a negative impression of the hand, that almost all of those are left hands, which implies perhaps that more of them were right handed because they were using the right hand to apply the pigment. But when you want to look at really ancient prehistoric people, the evidence is very conflicting. So we don't know when distinct human handedness emerged as we have it today, or why.

[Hannah Fry]

We can promise you an episode on that coming up at some point in the future. Here's a question from Aisha. Do taller animals get struck by lightning more often? If so, I guess it's dangerous to be a giraffe.

[Michael Stevens]

Do you know?

[Hannah Fry]

I do know.

[Michael Stevens]

What's the answer?

[Hannah Fry]

Yes.

[Unidentified Additional Participant]

Oh no.

[Hannah Fry]

Yes. But it's not the worst thing that can happen. So it is true, it is true that giraffes do get hit more often because they are sort of poking out of the savannah quite a lot more, which is a little bit tragic. There are also actual documented cases of giraffes getting hit by direct strikes during heavy thunderstorms. Actually, I think that there was, in 2020, there was an observational study, people out in South Africa, you know, watching what was going on and two giraffes were killed by a single bolt. I think they were standing quite close to each other.

[Unidentified Additional Participant]

Oh no.

[Hannah Fry]

So yes, it is more dangerous to be a giraffe, essentially.

[Michael Stevens]

Makes sense.

[Hannah Fry]

It is, but it's not the most dangerous thing when it comes to lightning because actually a direct hit from lightning from the sky is the least common way that the electricity can kill large animals. What is way more dangerous is because it's much more likely to hit the ground. And then you have this millions of volts of electricity that are rippling outwards through the soil. And here's the thing, thing. If you're an animal who is on four legs, yeah. Two of your legs are going to be further away from the site than the other two, which means that there is going to be a differential right between those two points. This is called a step voltage. It's totally deadly for four legged animals. And you know, you could maybe get really lucky where you were, you know, standing in a, in a way that was perfectly parallel with the rings as they, as they emerged. But at any other angle there's going to be this difference between your front

[Michael Stevens]

will pass through its body.

[Hannah Fry]

Yeah. Giraffes are more prone to this as well because obviously they're very big animals. Their front and back legs are really far apart. But this ground current effect, it was this incredible morbid mystery that sometimes you would see news reports of, you know, in History, more generally, you would see, I don't know, like, an entire herd of reindeer or like, dozens of cows that are just instantly killed in a single storm. And it can just take out an entire herd at the same time.

[Michael Stevens]

And it was probably because lightning hit the ground. The ground. And then a difference in charge between their feet across space got them all

[Hannah Fry]

this little electrical bridge, basically, that their bodies. Their bodies were the shortest path between the two.

[Michael Stevens]

So if I'm stuck in a field during a lightning storm, should I keep my feet together.

[Unidentified Additional Participant]

Yes.

[Michael Stevens]

And touch down on one leg or

[Hannah Fry]

get in a car?

[Michael Stevens]

Well, yeah, okay. If I had a car, then I consider myself not stuck in a field.

[Hannah Fry]

Or a giraffe. Yeah.

[Michael Stevens]

I wouldn't get in a giraffe. Giraffe. We've got a lot of books from this country for my daughter where the rhymes don't work in my accent.

[Hannah Fry]

Oh, really?

[Michael Stevens]

Yeah. There's one about like, put a scarf on a giraffe. And I'm like, marnie, that's my wife, you have to read this one. And she's like, oh, put the scarf on the giraffe. And I'm like, okay, that sounds ridiculous, but it rhymes now.

[Hannah Fry]

Excuse me. It sounds sophisticated.

[Michael Stevens]

It sounds sophisticated and sexy. Actually. She keeps saying that the New Zealand accent was voted the sexiest accent. I'm like, that must be a comedian's joke, because. Just kidding. I think it's obviously true, Marnie.

[Unidentified Additional Participant]

He listens to this podcast.

[Hannah Fry]

Yeah, I heard it was the Irish accent.

[Michael Stevens]

Are you serious? Wouldn't it should be.

[Hannah Fry]

Do you reckon they have a new vote every year?

[Michael Stevens]

British, Italian, French, Not British?

[Hannah Fry]

Come on.

[Michael Stevens]

Yeah, come on. Like a. Like a what. What was her name? Glamour Spice.

[Hannah Fry]

Glamour Spice.

[Michael Stevens]

Victoria Beckham. Who?

[Unidentified Additional Participant]

Posh Spice.

[Michael Stevens]

Posh. Posh Spice.

[Hannah Fry]

So are you joking? She's got, like, an Essex accent, I guess.

[Michael Stevens]

I haven't listened to her speak.

[Unidentified Additional Participant]

Oh, maybe that's why you think she sounds great.

[Michael Stevens]

But I would imagine Elizabeth Hurley.

[Hannah Fry]

Yeah.

[Michael Stevens]

That her accent is. It's sophisticated, right?

[Hannah Fry]

Like, that is very rp. Yeah. Yeah, yeah. I don't know. I think when people say English accent, I just imagine people from my hometown who are like, oy, shut up. Yeah.

[Unidentified Additional Participant]

Oh, my God. I don't think that's sexy at all,

[Hannah Fry]

but I imagine Italian people are the same. This question's from Paolo. I study statistics in Padua, Italy, which is in the middle of Pianura Padana, a region characterized by coldish, foggy winter days. I come from a city in the Alps that gets way colder than Padua. And whenever I tell my mom it was cold in Padua, she blames. Blames it on the dampness in the air, swearing that to her, a humid cold feels colder than dry cold, even when fully clothed. So is a 10 degrees Celsius, 80% humidity day colder than a 0 degrees, 50% day?

[Michael Stevens]

Well, I mean, yeah, it's colder because the temperature's lower, but it will feel different. The humidity does make a difference. Humidity makes a hot day feel hotter and a cold day feel colder because water is a much better conductor of heat. So if it's cold outside and the air is cold but really dry, you might not feel as bad because you're not losing heat as efficiently into the air. But if that air is the same temperature but much more humid, then you can have that heat taken away from you much more quickly. I remember experiencing, I think, in, like, North Dakota, a night where it wasn't even that cold. It was like 20 Fahrenheit, you know, it was below freezing, but it felt painfully cold. And I'm like, it's been this cold in Kansas before. And someone was like, the humidity is so high. But do you have anything else to say about this? Is that true?

[Hannah Fry]

Yeah. Yeah. No, I agree with you. I think one of the additional weird things here, I think this strange biological quirk that I can never get my head over is that humans actually can't sense wetness. Right. We don't have, like, a wetness center. The only way that we can tell that something feels cold is if. Is by the temperature differential to what we were expecting. I mean, you get this. If you put Veritasium did something on this recently. You put your hand in a glove and into a glass of water, and it feels like it's wet.

[Michael Stevens]

It feels wet. Yeah, I saw that too. And I've noticed that, too. Like, I will often wear gloves when I'm in the kitchen, and then I'll wash the gloves, and I'm like, hey, my hands got all wet. And I'm like, oh, no, they didn't. But, yeah, it's just that temperature difference. So you can tell the humidity of the air because of. I mean, how it's interacting with your skin. Exactly. And temperature change and also how it interacts inside your body with temperature change in your lungs. So.

[Hannah Fry]

But you're not actually physically feeling the wetness.

[Michael Stevens]

Funny enough, too. Humid air, do you think that it's more or less dense than dry air?

[Hannah Fry]

I would guess more.

[Michael Stevens]

It's less.

[Hannah Fry]

No.

[Michael Stevens]

Yeah, because water molecules, water vapor, which is what is in Air that makes it humid is just H2O. So it's two hydrogen atoms and one oxygen. That's it. And what is it replacing? It's replacing oxygen, which is two oxygen atoms, or carbon dioxide, which is carbon and two oxygen. Or it's replacing nitrogen, which exists as N2. So the water vapor is replacing molecules that are much heavier. So humid air is a lot less dense. Even though it feels like oppressively dense, it's not. And so there actually was a case where a baseball team got in trouble because they had an indoor baseball stadium, and whenever their opponents came up to bat, they would turn on the air conditioning to make the air thicker so that balls wouldn't go as far.

[Hannah Fry]

Wow.

[Unidentified Additional Participant]

Yeah.

[Michael Stevens]

And when they were up to bat, they would let the natural humidity come back in so that the air became thinner and balls were slowed down less.

[Hannah Fry]

That's incredible.

[Michael Stevens]

And they were told to stop.

[Hannah Fry]

Yeah, I mean, that's absolutely.

[Michael Stevens]

But that's really counterintuitive because humid air, you go down to, like, the Gulf coast, and you're just like, oh, this?

[Hannah Fry]

It's so thick.

[Michael Stevens]

The air is thick and it feels heavy, but it's actually much less dense.

[Hannah Fry]

Well, actually, I mean, if you. If I'd pause to think about it for longer. Of course, humid air has to be lighter because otherwise clouds, you know, clouds wouldn't work.

[Unidentified Additional Participant]

Clouds wouldn't be up there. They'd be down there.

[Michael Stevens]

I guess so. Well, if they come down, also, the pressure increases and the temperature goes up, so the water. Well, yeah, no, I'm sure you're right.

[Hannah Fry]

Yeah.

[Michael Stevens]

I don't know enough about it.

[Hannah Fry]

If clouds were really heavy and dense, then they'd be below.

[Michael Stevens]

But clouds aren't water vapor. Clouds are drops of liquid water that are visible. Oh, yeah.

[Hannah Fry]

Okay.

[Michael Stevens]

I take it water vapor is completely invisible, but once it condenses into droplets of water that float because they're so small, then you've got a cloud.

[Unidentified Additional Participant]

Okay.

[Hannah Fry]

All right. I take it back.

[Michael Stevens]

It's kind of like a pedantic thing I get into.

[Hannah Fry]

Clouds can stay where they are.

[Michael Stevens]

Like when you've got your kettle on and you see the steam coming out. No, you don't, because steam is water vapor, which is invisible. What you're seeing is water vapor, water in a gas form that has condensed into liquid droplets. And those are what you see as the white, smoky steam. But that's not steam. That's just hot drops of liquid water.

[Unidentified Additional Participant]

This is why we love you, Michael. Because there are very few other people on Earth who would be like, no, you're not seeing steam.

[Michael Stevens]

You can't see steam.

[Unidentified Additional Participant]

You can't see steam.

[Hannah Fry]

Okay, just to round off this episode, I've actually, I've looked up the. What has been voted the sexiest accent.

[Michael Stevens]

Okay, tell me.

[Hannah Fry]

Okay, the.

[Michael Stevens]

Wait, let me guess. Tell me. Two and three. Okay, tell me third place. Second place. I'll tell you first.

[Hannah Fry]

They kind of, they change around a little bit depending on who's asking. The who's asking, I'm sure. But the top four. We got all of the top four.

[Michael Stevens]

Okay, so the top four are French, Italian.

[Hannah Fry]

Not French, actually. Sorry.

[Michael Stevens]

Oh, what are the top four?

[Hannah Fry]

Italian, British, Irish, Kiwi.

[Michael Stevens]

Number one.

[Hannah Fry]

Yeah.

[Michael Stevens]

So my wife is right.

[Hannah Fry]

Yeah. In a heavily debated 2019 poll by Big 7 Travel, it took first place out of 50 accents. They described the New Zealand accent as outrageously charming, allowing it to beat out South African accent and the Irish accent.

[Michael Stevens]

Yeah, I stand corrected. That my wife is right.

[Hannah Fry]

There you go.

[Unidentified Additional Participant]

Yeah, there you go.

[Hannah Fry]

Your marriage can go on happily.

[Michael Stevens]

I'm trying to do an impression of a New Zealand accent, but it's going to be so offensive and wrong.

[Hannah Fry]

Go on, do it.

[Michael Stevens]

Anyway, I just think it's like this is my New Zealand accent. Oh, would you like a beer? Is that good?

[Unidentified Additional Participant]

I'm not sure what you were saying.

[Hannah Fry]

Go on the dick like that.

[Unidentified Additional Participant]

Go on the dick.

[Michael Stevens]

Yeah. Oh, that sounds better. I don't know why I make it so high pitched.

[Unidentified Additional Participant]

I enjoyed it so much more that you're just high pitched.

[Michael Stevens]

Let me try, like lower. I'll come out on the dick. Go be a sweet ass. That was good.

[Hannah Fry]

You know what?

[Michael Stevens]

Straight outta.

[Unidentified Additional Participant]

I think, I think that was undeniably sexy.

[Michael Stevens]

How do they say hello? Hello, I'm from the South Island. Eh? That was good.

[Unidentified Additional Participant]

I felt like I was there. That was.

[Michael Stevens]

And the north island is more like, hey, a sweet ass. Oh, give me some Milo.

[Unidentified Additional Participant]

Yeah.

[Hannah Fry]

It is a wonder that you didn't

[Unidentified Additional Participant]

choose acting as your career, isn't it? It absolutely is.

[Michael Stevens]

I think, I think that if you've been offended today, let us know. You can email us at thereestiscienceoldhanger.com send

[Hannah Fry]

us in your questions, your ideas, things you want us to answer, and any

[Unidentified Additional Participant]

medical advice for somebody who's consumed a small amount of fellow polymetallic nodules.

[Michael Stevens]

See lead nodules. Goodness me.

[Unidentified Additional Participant]

See you next time.

[Gordon Carrera]

Why did we really go to war with Iraq?

[David McCloskey]

And did Saddam Hussein really have weapons of mass destruction?

[Gordon Carrera]

I'm Gordon Carrera, national security journalist.

[David McCloskey]

And I'm David McCloskey. Author and former CIA analyst. We are the hosts of the Rest Is Classified. And in our latest series, we are telling the true story of one of history's biggest intelligence failures. Iraq WMD.

[Gordon Carrera]

In 2003, the US and UK told the world that Saddam Hussein had weapons of mass destruction. But they were wrong.

[David McCloskey]

This wasn't a simple lie. It was something far more complicated, far more interesting, and far more dangerous.

[Gordon Carrera]

Spies who believed their sources, politicians who wanted the public to believe believe in the threat, and a dictator who couldn't prove he'd already destroyed the weapons.

[David McCloskey]

In this series, we go deep inside the CIA and MI6, go into the rooms where decisions were made, and look at the sources who fabricated the intelligence that took us to war.

[Gordon Carrera]

The Iraq war reshaped the Middle east and permanently weakened public trust in governments and intelligence agencies. And its consequences are staggered. Still playing out today.

[David McCloskey]

Plus, in a Declassified Club exclusive, we are joined by three people who were at the heart of the decision to go to war. Former head of MI6, Richard Dearlove, Tony Blair's former communications director, Alistair Campbell, and former acting head of the CIA, Michael Morell.

[Gordon Carrera]

So get the full story by listening to the Rest Is Classified and subscribing to the Declassified Club. Wherever you get your podcasts,