Name: 慢動作中的鐵流體--60個符號。 (Ferrofluid in Slow Motion - Sixty Symbols)
Uploaded: 2021-01-14T10:31:46.000Z
Duration: 6 min 36 s
Description: 【看影片學英語】數萬部 YouTube 影片，搭配英漢字典即點即查，輕鬆掌握單字發音與用法，長久累積看電影不必再看字幕。

Fair food in the dish also say looks fairly innocuous now.

Let's do the magic first way are talking about fair fluids.

This wonderful Well, it looks pretty innocuous.

About this time last year, I went into my daughter's school.

Andi, I've never seen a bunch of eight year olds get so excited about a piece of science.

Dua 60 symbols video and let me cut to the cheers.

In fact, they say that you should dispose of it.

A told you don't need to stand back Pretty.

What we're gonna do now is captured the dynamics of how this fair of fluid response for a magnetic field would have been a magnet in up underneath it on Ben, take it away on.

We're gonna look with a high speed camera.

I'm absolutely surrounded by cameras here.

It's a very big sort of Hollywood production compared to the usual Brady carrying a camera on his shoulder.

So what you bring the market up from from below.

Basically, the influence of the magnetic field is changing, and that's giving you different spikes as the favorite fluid fields of greater influence of the magnetic field.

Balanced against that is the surface tension, which is trying to hold the liquid together on so you about these two competing effects from the period is little spikes.

You can work out lots of fascinating things about the dynamics of the fluid and also the property.

I stupidly brought the magnet to the top service and jumped out of my hand.

The fun bed is when you put the magnet on the top and watch it go up to that.

But then we will have to stop the video because I'll have to spend at least an hour cleaning myself.

Or magnetism comes from the interactions off spins on what we basically do to represented what physicists do represent.

We take the electrons, and we think of them basically has either been spent up or spend on.

What happens is when you put the magnetic field on.

It'll spins a line right on there, lying right across the solid.

So with pharaoh magnets with the magnet you used to.

When you take the magnet away, their spins remained aligned, and you're left with what we call a permanent magnetic moment in things called power magnets.

What happens is that when you bring the magnetic field in, you can align them.

But when you bring it away, they no longer remain aligned.

That's exactly what's happening with these fair foods.

So we're gonna move away from considering the sort of individual atoms of the individual electrons and think about a nano particles comprises tens of thousands of up to 100,000 atoms on dhe, each one of those particles, the electrons in them.

What happens in the particle is that the particle ends up despite the fact that is comprising lots and lots of atoms ends up with one big nets.

Been we call it a single demand particle.

Now what's happening in the absence off the magnet in the fairy flutes.

So just as it stands just as it is like here, those particles are bouncing around, bumping off all the particles moving around like you would expect, you know, particles in a liquid to do, and so the spin get scrambled and they don't align when you bring the magnet in.

What's happening is you're getting the spins of those particles all to align, and you see in the collective response of all those particles responding to magnetic field, lining up on interacting with each other.

Take it away again on your back to the fluid.

When I bring you, why don't your atoms and a very good question really Certain things are magnetic?

All the things are not magnetic, and it depends on how the electrons are arranged in the solid.

A magnetic or not power genetic, and that's because busy the elections are not free to a line in the same way as they are in iron, for example, or the fire magnetic materials.

So the particles in this liquid are magnetized.

So in iron oxide on what they're coated with is something called a surfactant, which means that the particles are the surfaces of the particles are quite passive.

They come together, but then they don't chemically bond.

It's what we call a physical interaction.

It's a physical attraction, no chemical bonding on.

Then when you bring the magnet away that can release easily and then the bumping into each other in the solution.

But they're not forming chemical bonds, so you might think it's a fairly esoteric, you know, product.

But where it crops up all the time isn't hard.

This technology, actually the spindles that are associated with tar discs where the hardest is spinning around that is lubricated, actually fairly fluid.

So you have to get a first time Brady because I'm gonna get covered in stuff.

I'm gonna bring it in both of the fair of fluid instead of putting the magnet from below was seen before.

 When I bring it in from the top, let's see what happens. 