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- [00:02]
A
Hello. The Rest is politics, us listeners, I'm Michael Stevens.
- [00:06]
B
And I'm Professor Hannah Fry. Well, firstly, thank you to Cassie and Anthony for letting us take over the channel. Just to tell you about our new show for Goal Hanger. The Rest Is Science. Every week we take a fresh look at the familiar. We're going to be exploring the forces, the theories and the phenomena that shape how we live in, think about and see the world. We're going to pull apart what we take for granted to reveal the unexpected patterns and, and hidden logic just beneath the surface.
- [00:34]
A
Because that's what moves science forward. Not the polishing of answers, but the sharpening of questions. It's curiosity that sparks those. Hey, wait, how does that actually work? Kind of a moment that changes the way we see the world.
- [00:46]
B
So, okay, here is a little glimpse of what is to come from our podcast. And if it sparks something unexplainable for you, then you can join us every Tuesday and Thursday for new episodes of the Rest Is Science. And we'll figure it out together.
- [01:01]
A
You mentioned earlier that a cup of water is like a rock smoothie. Right. Because you've got rocks dissolved in it, magnesium and calcium. I would go a step further, though, and say that a glass of water is actually just a glass of lava, because I've talked about this before and I bring it up whenever I can. Ice is a rock.
- [01:25]
B
Sure.
- [01:26]
A
Because. Well, hold on. Ice is a mineral, because a mineral is just a inorganic material that is solid and has a definite crystal structure, which ice does. Water is important for life, but it's inorganic. Actually, it would exist here whether there was life or not. And what that then means is that a cube of ice is made of a mineral, so it's a mono mineralic rock. So melted ice is molten rock, lava. So water is lava. I'm here for this and this is not a joke. Ice won the mineral cup back in 2015, I believe. Like some geologists all voted on their favorite mineral and ice finally got the recognition it deserves.
- [02:11]
B
Yeah. Got the prize.
- [02:12]
A
Yeah.
- [02:14]
B
I mean, sure, I'm happy with that classification if the rock people say it. So then I'm happy with it. They also move the same way. I mean, when lava gets spurted out of volcano, it's. It uses. The way that it moves and behaves is exactly the same.
- [02:28]
A
The fluid dynamics of lava.
- [02:29]
B
Fluid dynamics of lava is the same as water at that stage. Yeah. Bit later on when it cools down, then it changes.
- [02:36]
A
Is it more like ice?
- [02:37]
B
More like ice. There's a transition phase where it's more like toothpaste where it needs a certain amount of shear forces in order for it to flow.
- [02:44]
A
But that would be analogous to like slush, maybe.
- [02:46]
B
Maybe, yeah. So now that we've established that ice is a mineral and that water is lava, I think we'll take a little break. Okay, welcome back from the break. What we've established is that water is lava, but also everything that you drink and eat is also water. Therefore everything you consume is lava.
- [03:13]
A
Pretty much. Pretty much. But let's talk more about the water on Earth and like how much there is and what form it's in, because I think we in our day to day lives are very biased to think of water as this splashy puddle stuff. It's in lakes and rivers, but that is basically not what water is on Earth at all.
- [03:31]
B
Go on.
- [03:32]
A
Well, Earth has a lot of water and it's famous for having a lot of water on the surface. But it's not water that we can just come up and drink because it's too salty. Most of Earth's water is way too salty. It would kill you to drink it.
- [03:45]
B
Wait, when you say most, what are we talking here? What percentage of the water is?
- [03:48]
A
I'll tell you. I'm gonna have to pull up a chart because I want to get these number numbers just right. So here's the deal. Earth has a lot of water, but of all that water on the entire planet, both on it and in it, only 2.5% is fresh.
- [04:03]
B
Meaning the rest is salty, not salty,
- [04:05]
A
and the rest is salty. But that 2.5% sounds small. But what we're looking for is even smaller because out of that two and a half percent, almost 70% is frozen in glaciers and ice caps, so not accessible to just come up and sip. And then another 30% of that is groundwater, not up on the surface. So only 1.2% of the two and a half percent that's fresh is on the surface, basically.
- [04:33]
B
So wait, wait, it's one percent of the two and a half percent.
- [04:36]
A
One percent of the two and a half% is surface fresh water. But we're still not done because surface is being used really broadly here. That includes 3% of, of that 1% of the 2% is water in the atmosphere.
- [04:50]
B
Right?
- [04:51]
A
This is very small, but it's worth mentioning. 0.26% of that little sliver is locked inside living organisms.
- [04:58]
B
Right? And then it's in your beef jerky.
- [05:01]
A
Almost 4% of that little sliver is dampness in the soil. So I can't Just go up and, like, slurp it up. I could stick some mud in my mouth and, like, try and suck on it. We suck on it. But what we think of as fresh water, water from creeks and springs and rivers and in lakes, that is. I did the math here. 0.0072% of all the water on Earth.
- [05:29]
B
Wow.
- [05:30]
A
It is a tiny minuscule fraction of the 1% of the 2 1/2% that's not salt water.
- [05:38]
B
And if you think about it, all of the water that we effectively come into contact with, all of the water we're drinking, all the water we're showering with, all the putting in swimming pools, all of that is contained within that number.
- [05:51]
A
0072%. Yeah. But it's the water that is the star of the human show. It's what we swim in. It's what we get out of the tap and that we drink and that we have right here. There is no salt water around us right now.
- [06:05]
B
No, I'm not interested in the salt water, thank you very much.
- [06:07]
A
We're interested in such a narrow kind
- [06:09]
B
of water of that tiny, tiny sliver. How much of that is in Coca Cola? How much of that is tied up in.
- [06:15]
A
Yeah. How much is tied up in warehouses, in cans of soda and beer and brewed tea? Yeah. I don't know. I do know. Here's a fun fact. The entire volume of refrigerated space in the United States is equal to two thirds the volume of Mount Everest.
- [06:37]
B
Really?
- [06:38]
A
I can't tell if that sounds small or big.
- [06:41]
B
I think that sounds big. And the reason why I think it sounds big. I'm slightly obsessed with fridges.
- [06:46]
A
Yeah.
- [06:48]
B
Which I appreciate isn't a normal sentence, but they're wild. Like, they are tricking the laws of thermodynamics.
- [06:55]
A
I know.
- [06:56]
B
It's like you have managed to create this sort of tiny bubble in the universe where you have, like, sucked energy away. That's not what energy likes to do. Like, it is miraculous that fridges have managed to work.
- [07:09]
A
I know. And they do it so simply.
- [07:11]
B
So simply.
- [07:12]
A
They're just squirting around a fluid. And the fluids properties are like, let's do it. Let's dump this heat out. Keep your yogurt nice.
- [07:18]
B
And I mean, also, just think about before fridges existed. Right. You could have lived, I don't know. For, like, most of the planet would never have experienced a cold drink. Right.
- [07:31]
A
I know.
- [07:32]
B
Like, it's just. It's wild to me that we've had this thing for like a hundred Years or so, Maybe a little bit more. 150 or so. I find fridges. Really? Can we do a whole episode on fridges, please?
- [07:41]
A
Yeah, we should. But where did all this water come from on Earth? How old is it? How long has it been around?
- [07:46]
B
Well, it didn't get made on Earth, Right? That's one thing that we know.
- [07:49]
A
Water isn't produced naturally on Earth, right?
- [07:51]
B
Correct. Which means it came here from space.
- [07:54]
A
Alien water.
- [07:55]
B
Alien water, yeah.
- [07:57]
A
I've heard that it probably came from, like, comets that crashed into a dry Earth and they left all this ice. It's hard to imagine, though, how many comets that would be. I guess that's why they call that the heavy bombardment period, when Earth was just getting smacked by these comets from way out beyond the solar system. Made of ice, covered in ice, and they just delivered the oceans to us over time.
- [08:22]
B
Do we know how old the water is then?
- [08:24]
A
More than half of the water on Earth is older than the sun.
- [08:29]
B
How do they know that?
- [08:31]
A
Water can form naturally. It's an inorganic material. It's a molecule that can form all throughout the universe. And we know this because of a couple of things. One, when the sun formed, any water near the sun would have been obliterated into oxygen and hydrogen. Just elemental or molecular forms. Wouldn't be water anymore. And so any of the water that remained would have had to have been further out where it couldn't get destroyed by the sun forming. And then later, as the formation was complete, that water could fall down to Earth. And I think they've been able to test this by looking at the amount of heavy water in water on Earth and compare it to how water could have been formed more recently in the solar system.
- [09:17]
B
And by heavy water.
- [09:18]
A
Right. I mean water, where the hydrogen atoms in it are deuterium. Which is what? Hydrogen with one neutron? Yeah, yeah.
- [09:28]
B
Chubby hydrogen.
- [09:29]
A
Chubby hydrogen. So it's still hydrogen, because all you need to be a hydrogen atom is one proton with a little electron around. You get a little neutron in there, you're heavier, but you don't have any more protons. So your chemical properties are pretty similar. So it's still hydrogen, but it's called heavy. Sam.