How to Make an Elephant Explode – The Size of Life 2 - video Dailymotion

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How to Make an Elephant Explode – The Size of Life 2

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00:00Let's shrink an elephant to the size of a mouse, and enlarge a mouse and make it the

00:06size of an elephant, because this is our video and we want to see what happens.

00:09First, our now tiny elephant stumbles around and then drops dead.

00:14Tiny elephant buddy is very cold, frozen to death in minutes.

00:18Our giant mouse looks very uncomfortable for a moment, and then it explodes, leaving hot

00:23mouse insides everywhere.

00:25Why?

00:27Because of size.

00:28We are optimized to function precisely for the size we are, and would die horribly in

00:32any other environment.

00:33But why exactly?

00:35Why does our mouse explode, and can we do this to our elephant too if we try hard?

00:41Life on this planet is based on cells.

00:44Cells do vary in size, but they're pretty similar in their dimensions across all species.

00:49A blue whale doesn't have bigger cells than a hummingbird, just a lot more of them.

00:54Animals have to do a lot of stuff to stay alive, and they need energy to be able to

00:57do so.

00:58To get this energy, animal cells convert food and oxygen into usable chemical energy.

01:05This happens in our mitochondria, the powerhouse of the cell.

01:09They're like little coal engines that spit out tiny ATP batteries, which the cell can

01:13use for almost everything it needs to do.

01:16Just like an engine, mitochondria get really hot while working.

01:20In human skin cells, they reach a scorching 50 degrees Celsius.

01:24And some of our cells have up to 2,000 mitochondria which are radiating their heat into the cell.

01:30So being alive generates a lot of heat.

01:33The more cells you have, the more heat your body generates in total.

01:37If our bodies didn't find ways of losing this heat, we would be cooked from the inside and

01:41die.

01:42But this is a problem for bigger animals because of the way bodies change as living beings

01:47scale up.

01:49Animals have three properties here that are important.

01:52Their length, their outsides or skin, and their insides like organs, bones, and hopes

01:57and dreams.

01:58The thing that's hard to wrap your head around is that when things grow, their insides grow

02:02faster than their outsides.

02:05Imagine a fleshy cube.

02:07If you double the length of its sides, its surface and volume do not double.

02:12In fact, the surface is now four times the original size and the volume of the cube eight

02:16times the original size.

02:19Which is called the square cube law and has been annoying nature for billions of years.

02:24So why is this a problem for big animals?

02:27Because heat can only leave an object via its surface.

02:30So if we make our mouth the size of an elephant or 60 times longer, it has 3,600 times more

02:37surface from which to lose heat.

02:39But it has 216,000 times more volume filled with trillions and trillions of new hot mitochondria

02:46that produce more heat.

02:48A lot more insides, not that much more skin.

02:51Our mouse is very dead very fast.

02:55But big things like elephants exist, so how do they deal with the heat?

03:00For one, they evolved ways to get rid of energy more easily, like huge flat ears that have

03:05a lot of surface where heat can escape.

03:08But that's not enough.

03:09Nature's solution is actually very elegant.

03:13Elephant cells are much, much slower than mice cells.

03:17The bigger an animal is, the less active its cells are.

03:20If we classify animals by their metabolic rates and compare that to their overall mass,

03:25it's clearly visible.

03:27It's not 100% accurate, but it is a good rule of thumb.

03:31Elephants are huge meat sacks filled with trillions and trillions of little coal ovens.

03:36So they keep the ovens just active enough to keep them running and never at full power.

03:41Their whole metabolism is slow.

03:43Things move at a nice, chill pace.

03:46All animals need to go the exact opposite way.

03:49If you're small, you have a lot of surface area compared to not a lot of volume.

03:54You don't have a lot of cell ovens and lose the heat they produce very fast.

03:59So very tiny mammals came up with a very extreme solution.

04:03Meet the Etruscan shrew, the smallest mammal on Earth, a mole-like thing that's more closely

04:08related to hedgehogs than to mice.

04:11At a body length of 4 centimeters, it only weighs about 1.8 grams, as much as a paperclip.

04:17It's a tiny, ridiculous being.

04:19It would basically cool off immediately, so its cells run on overdrive to stay warm.

04:24Its tiny ovens are filled at maximum capacity.

04:27Its heart beats up to 1,200 times a minute, and it breathes up to 800 times a minute.

04:33This creates an extreme need for energy, so the shrew has to eat constantly.

04:38For only four hours without food, it starves to death.

04:42And while an African elephant consumes around 4% of its body weight in food each day, our

04:46shrew needs 200% of its body weight in food a day just to survive.

04:51Imagine having to eat 2,000 Big Macs a day, more than one a minute.

04:55Fun for a while, but then not so much.

04:58So a cubic centimeter of shrew needs 40 times more food than a cubic centimeter of elephant.

05:04If an elephant's cells suddenly become as active as the cells of a shrew, a crazy amount

05:08of heat would be generated.

05:10All the liquids in the elephant would suddenly start boiling, and then it would explode in

05:15an impressive explosion of steaming hot, burning elephant parts.

05:19In reality, before an explosion occurred, the proteins making up our cells would probably

05:23be denatured and stop producing heat.

05:26But a meat explosion is much more fun than melting an elephant into a mass of hot goo.

05:31Regardless, the scaling of the speed of metabolism happens everywhere, even in places we don't

05:36expect, like pregnant women.

05:39A baby in the womb of its mother behaves as if it were a part of her.

05:43Its cells have about the same metabolic rate, the same speed of life as its mother's organs.

05:48It is truly a part of a bigger whole rather than an individual.

05:52Until it's not anymore.

05:54The very moment a baby is born, a switch is flipped, and all its internal processes speed

05:59up rapidly.

06:0136 hours after birth, the baby's cells have the same activity rate as a mammal at size.

06:08Babies literally transition from being an organ to being an individual in mere hours.

06:13But there's one thing where big and small things are very similar, heartbeats.

06:18Mammals tend to have a similar amount of heartbeats over their lifetime, typically around 1 billion.

06:24So while the shrew and elephant are very different, they share a similar number of heartbeats

06:29over the course of their lives.

06:32Their speed of life is the opposite, and somehow still the same.

06:36And for a video in which we made elephants explode for no good reason, this is the most

06:41romantic ending we could come up with.

How to Make an Elephant Explode – The Size of Life 2

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