A Ball of Water
Imagine if you could pick up a drop of water, and carry it, just like that?
Imagine if you could pick up a drop of water, and carry it, just like that?
Sixteen thousand new plastic bottles are made every second. One week from now, there’ll be enough new ones to circle the Earth five times over.
The main reason for all these bottles is humans. Human immune systems are so weak, they can’t drink most water they find. The water has to be clean. Very clean.
In fact, many humans use special machines to take everything out of water: that’s how clean they need it to be.
That’s all very well at home. But what if the humans are out on a long journey? That’s when they’ll need to take water with them — or at least, find a way to get clean water wherever they go.
That’s where the plastic bottles come in.
Earlier, humans didn’t travel as much as they do now. And when they did, they had to come up with ways to keep their water supply accessible. They would put it into containers like pots or waterskins — or, as in the case of bushmen, just drink as much as they could before leaving and then hope to find more on the way.
All those ways worked well, but then humans came up with an even more convenient device: the water bottle.
Nowadays, humans don’t even need to carry water. There are shops on the way where they can just pick up a plastic bottleful. And the bottles are so cheap and easy to make that people don’t even bother saving them. They just throw them away, and then pick up a new one when they need it.
That’s very convenient for thirsty humans, but it’s not convenient for anyone else. First of all, making water-bottles is very energy-intensive. Secondly, it takes more water to make a water-bottle than to fill it. Most of those bottles are then thrown away, littering the land and the oceans. And many water-bodies are getting too polluted to drink, because of chemicals from factories that make water-bottles.
The main problem is that humans need a container to carry water, and the container they happen to use is very polluting. But imagine if humans could pick up a piece of water, and carry it, just like that?
If humans were the size of ants, you wouldn’t have to imagine.
Humans are so large and big that they experience the world very differently from smaller creatures. To humans, a bumpy field, with all its mountains and valleys and cracks and crevasses, would seem “flat”. And water would always seem liquid, with no way to pick it up and hold it at all.
The Honeypot ant is a special kind of ant. Because it lives in a very dry area, it’s worked out a way to store food and water when times are good, and save them for a non-rainy day. But it doesn’t use a bottle or a pot. Instead, young honeypot ants volunteer to eat the food and water, and store it inside their own bodies.
But how does the food and water get to them? The other worker ants carry it. Yes, the water, too.
Ants are so small that they can just pick up water the way a human can pick up a football. But footballs are solid, while water is liquid! So, how does that work?
Because of something called “surface tension”.
What you see as water is actually made up of many molecules. These molecules are tiny; to an ant, they would be much smaller than an ant is to a human.
Normally, the molecules are all pulling onto each other. That’s why water doesn’t break apart into bits. It stays together and flows.
But on the surface of the water, the molecules don’t have anything pulling them up. They’re only being pulled down, by the water molecules below.
That’s why they tend to stick on slightly harder — because there’s more pulling happening in that direction. This extra pull also makes the surface of water more springy and stretchy. That’s how water skaters manage to skim the water without breaking through the surface and sinking in.
Because all the surface water is being pulled inwards, water always ends up with as few molecules on the surface as possible. That’s why it naturally ends up being shaped like a ball.
But wait a minute! Doesn’t water flow in streams? Doesn’t it fill puddles and vessels, and always take the shape of the container it’s in?
No. It only does that because there’s something squishing it down.
If you were an astronaut, floating up in the weightlessness of space, you could let out a bit of water from a bottle and see it take its natural shape. You would see it form a ball before your eyes. You would be able to hold it in your hand. You would be able to move it around, as long as you didn’t do it too suddenly and smash it to bits.
And then you would get fired for fooling around and risking an accident, and you wouldn’t be allowed to go up into space again.
So, don’t fool around with water. Look towards the Earth.
From the International Space Station, you would see the Earth below you with a curving horizon. But if you could go even further out, you would be able to see the true shape of the planet.
A ball — a sphere — is the shape with the lowest surface area for any certain volume. It’s not just water that takes this shape. It can be anything that wants to hold as much as possible while exposing as little as possible to the outside world. That’s why stuffed sacks and cartons of melting ice-cream bulge in the way they do: because they’re trying to hold more. That’s why they become roundish, instead of becoming squarish or trianglish or anything else.
But if you sit on an ice-cream carton, it becomes flat.
The same thing happens when water is down on Earth. It’s as if the great force of gravity is sitting down on the water and flattening it. That’s why, when people see water, the usually see it crawling around on the surface. Unless it’s got something like a pot to hold it up.
If you go down under the powerful gravity of Jupiter, you would become flat too. Jupiter’s gravity is so strong that diamonds can form in the air and fall down like rain, but you wouldn’t notice.
You wouldn’t be alive enough to notice anything, really.
Under such strong gravity, you would collapse under your own weight. The bottom part of you woldn’t be able to hold up the rest of you. You would be like a beached whale with a skeleton too weak to support the weight of its body without the help of water to hold it up.
If you were smaller, you might have had a chance.
On Earth, when water is smaller, it has a chance.
Have you seen drops of water dripping from a leaky tap? Or morning dew dripping off the tip of a leaf? The drops may seem a bit pointy at the top, but apart from that, they’re mostly round.
Like a ball.
Droplets of water are tiny enough that they can keep their shape even under Earth’s gravity. They’re light enough to support themselves. And they’re also the perfect size to be picked up by an ant.
Wouldn’t it be nice if humans could somehow take that surface tension, and make it stronger, so that they could pick up water too? A new invention does almost that. Not by changing the surface tension, but making a whole new surface to put around the water.
The Ooho is a round, biodegradable package made from seaweed. Designed by a team from Skipping Rocks Lab, this transparent package is flexible, and yet strong enough not to break easily. People can fill it with water, and carry it around where they like.
The Ooho design has been put out for the public to use, so anyone can make it at home — providing they have access to some ‘sodium alginate’ and ‘calcium lactate’. It’s completely edible. When you get thirsty, you can just pop it in your mouth.
And it’s the closest humans have ever got to holding a ball of water.
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