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It`s Okay To Be Smart, The Weird Science of the Raisin Bran Effect

The Weird Science of the Raisin Bran Effect

Hey smart people, Joe here. You know what I freakin' love? Cereal. You know what I

hate? The cereal at the bottom of the box.

Ever notice how by the time you get to the bottom, you're left with this? It's just

little crumbs and boring stuff. The dregs, if you will. The tastiest big bites

are gone. But… that doesn't really make sense. If cereal is mixed in the

box, shouldn't it stay that way? Or if anything, why doesn't the bigger, heavier stuff sink to the bottom?

Watch what happens when I shake up this bag.

When I pour the cereal out, there's more delicious bits in the first bowls, from the top of the bag.

Why does this happen?! The answer… is science.

Well, technically that's the answer to everything. But especially this!

Ok, back to why does this happen… Well it's curious that the heavier bits rise to the top instead of falling to the bottom.

Well the same thing happens with granola and …nuts.

Shaking a can of mixed nuts doesn't actually

mix them up… it UN-mixes them, and big nuts like Brazil nuts always rise to the top.

That's why this strange phenomenon is commonly called the “Brazil Nut Effect,” though

I don't really like Brazil nuts, and I LOVE Raisin Bran, so I'm renaming it the Raisin Bran Effect!

And it's powered by physics.

When we shake something up, we expect it to get more random.

But for many mixtures, that isn't what happens. Shaking them actually makes them less random.

Scientists started digging into this strange phenomenon in the late ‘80s, and how it works is still kind of

driving them nuts.

The key ingredient is motion. To make particles

move, we have to accelerate them. And for these particles, that means accelerating them

enough that they overcome gravity.

They bounce, or jump, and that allows them to rearrange.

There are a couple different mechanisms going on here.

One is called granular convection. Granular means it's made up

of small grains or particles, and moving by convection, a sort of rolling flow.

In a container, as things get vibrated and

jostle around, the friction between the grains and the side walls draws particles near the

edges down. Particles near the center are pushed up, and we get convection swirls.

Even if there's a big dense object in the

mix, it gets shoogled up the middle by the convection currents - and it stays there.

That's right, I said “shoogled”.

It's a new Scottish word I learned that means “to shake”… and it is awesome.

But there's another way this sorting can

happen besides convection: it's called percolation.

Basically small particles fall into the cracks left by their bouncing neighbors. And as they

fill in those spaces, the bigger particles get pushed towards the top.

Think of it like a ball bouncing on a platform that levels up every time the ball jumps.

We can see this in a really cool way with

some sand, some salt and this thing I built.

Watch what happens when I pour it through this little hole.

See that? They separate!

If we look closely, we can see that when the

different grains impact, they're still pretty mixed, but as they settle, the layers start building.

Larger grains quickly roll down the hill, but the smaller grains get

stuck in cracks along the way. As the small stuff fills in empty spaces, large particles

roll along on top of it. The process repeats, and that

gives us those nicely stratified layers.

Ok - so this is cool and all, but do percolating

particles and granular convection actually matter in the real world?

It does if you're caught in an avalanche.

Avalanche airbags inflate around a person tumbling and being buried by snow.

They don't float you up, the way a lifejacket floats

you in water. They basically turn you into a human brazil nut, a big particle rising

in a mix of smaller snow!

Physics can save lives. Who knew!? Actually…

car airbags, seatbelts, ejection seats, bulletproof vests, MRIs. I guess that's not really news.

Anyways…

Even rocks in river beds separate this way,

the larger ones on top. And it shows up in space! It's one explanation for large boulders

on the surface of asteroids that have no other business being there.

Best part? You can try this at home! Shake a bowl of popcorn to get the biggest, fluffiest

kernels to the top. It even works with a bowl of chips.

In fact, I want to know where you find this effect. Send me a video the next time YOU

see the Brazil Nut Effect… I mean the Raisin Bran Effect, in action.

Stay curious.

And it's good for you, too!

The Weird Science of the Raisin Bran Effect Die seltsame Wissenschaft des Rosinenkleieffekts La extraña ciencia del efecto salvado de pasas De vreemde wetenschap van het rozijnenzemelangeffect A estranha ciência do efeito Raisin Bran Странная наука об эффекте изюмных отрубей 葡萄乾麩皮效應的奇怪科學

Hey smart people, Joe here. You know what I freakin' love? Cereal. You know what I Hey slimme mensen, Joe hier. Weet je waar ik gek op ben? Graan. Weet je wat ik Гей, розумники, це Джо. Знаєте, що я до біса люблю? Пластівці. А знаєте, що я

hate? The cereal at the bottom of the box. een hekel hebben aan? Het graan op de bodem van de doos.

Ever notice how by the time you get to the bottom, you're left with this? It's just

little crumbs and boring stuff. The dregs, if you will. The tastiest big bites

are gone. But… that doesn't really make sense. If cereal is mixed in the

box, shouldn't it stay that way? Or if anything, why doesn't the bigger, heavier stuff sink to the bottom?

Watch what happens when I shake up this bag.

When I pour the cereal out, there's more delicious bits in the first bowls, from the top of the bag. Als ik de cornflakes uitgiet, zitten er nog meer heerlijke stukjes in de eerste kommen, vanaf de bovenkant van de zak.

Why does this happen?! The answer… is science.

Well, technically that's the answer to everything. But especially this!

Ok, back to why does this happen… Well it's curious that the heavier bits rise to the top instead of falling to the bottom. |||||||||||||particles components elements||||||||||

Well the same thing happens with granola and …nuts.

Shaking a can of mixed nuts doesn't actually

mix them up…  it UN-mixes them, and big nuts like Brazil nuts always rise to the top.

That's why this strange phenomenon is commonly called the “Brazil Nut Effect,” though

I don't really like Brazil nuts, and I LOVE Raisin Bran, so I'm renaming it the Raisin Bran Effect! Ik hou niet echt van paranoten, en ik ben dol op rozijnenzemelen, dus ik hernoem het het rozijnenzemeleneffect! Я не дуже люблю бразильські горіхи, але обожнюю висівки з родзинками, тому перейменовую їх на "Ефект висівок з родзинками"!

And it's powered by physics.

When we shake something up, we expect it to get more random.

But for many mixtures, that isn't what happens. Shaking them actually makes them less random.

Scientists started digging into this strange phenomenon in the late ‘80s, and how it works is still kind of

driving them nuts.

The key ingredient is motion. To make particles

move, we have to accelerate them. And for these particles, that means accelerating them

enough that they overcome gravity.

They bounce, or jump, and that allows them to rearrange.

There are a couple different mechanisms going on here.

One is called granular convection. Granular means it's made up

of small grains or particles, and moving by convection, a sort of rolling flow. ||grains||||||convection|||||

In a container, as things get vibrated and

jostle around, the friction between the grains and the side walls draws particles near the

edges down. Particles near the center are pushed up, and we get convection swirls.

Even if there's a big dense object in the

mix, it gets shoogled up the middle by the convection currents - and it stays there. |||shaken||||||||||| mix, wordt het door de convectiestromen naar het midden geslingerd - en het blijft daar.

That's right, I said “shoogled”. ||||shook Dat klopt, ik zei "shoogled".

It's a new Scottish word I learned that means “to shake”… and it is awesome.

But there's another way this sorting can

happen besides convection: it's called percolation. |||||percolation

Basically small particles fall into the cracks left by their bouncing neighbors. And as they

fill in those spaces, the bigger particles get pushed towards the top.

Think of it like a ball bouncing on a platform that levels up every time the ball jumps.

We can see this in a really cool way with

some sand, some salt and this thing I built.

Watch what happens when I pour it through this little hole.

See that? They separate!

If we look closely, we can see that when the

different grains impact, they're still pretty mixed, but as they settle, the layers start building.

Larger grains quickly roll down the hill, but the smaller grains get

stuck in cracks along the way. As the small stuff fills in empty spaces, large particles

roll along on top of it. The process repeats, and that

gives us those nicely stratified layers. ||||layered|

Ok - so this is cool and all, but do percolating |||||||||filtering through

particles and granular convection actually matter in the real world?

It does if you're caught in an avalanche.

Avalanche airbags inflate around a person tumbling and being buried by snow. ||||||rolling||||| Лавинні подушки безпеки надуваються навколо людини, яка падає і засипається снігом.

They don't float you up,  the way a lifejacket floats

you in water. They basically turn you into a human brazil nut, a big particle rising

in a mix of smaller snow!

Physics can save lives. Who knew!? Actually…

car airbags, seatbelts, ejection seats, bulletproof vests, MRIs. I guess that's not really news.

Anyways…

Even rocks in river beds separate this way,

the larger ones on top. And it shows up in space! It's one explanation for large boulders ||||||||||||||||boulders

on the surface of asteroids that have no other business being there.

Best part? You can try this at home! Shake a bowl of popcorn to get the biggest, fluffiest

kernels to the top. It even works with a bowl of chips.

In fact, I want to know where you find this effect. Send me a video the next time YOU

see the Brazil Nut Effect… I mean the Raisin Bran Effect, in action. zie het Paranoot-effect ... ik bedoel het Raisin Bran-effect, in actie.

Stay curious.

And it's good for you, too!