Name: 水銀蒸気を見る - 動画の周期律表 (Looking at Mercury Vapour - Periodic Table of Videos)
Uploaded: 2021-01-14T10:14:00.000Z
Duration: 4 min 8 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

But like most heavy metals, it is poisonous.

It's quite surprising to people, if you have this liquid running around in a dish or something, how can it possibly poison you if you're not touching it?

The answer is that there is vapour of mercury coming off, which you can breathe.

And, remarkably, it's quite easy to show you how this vapour comes off.

I have to explain a little bit about mercury lamps.

UV light can be generated by filling a tube with a small amount of mercury

and then passing through an electric current.

The electric current heats the mercury to a very high temperature

and the mercury atoms give out ultraviolet light.

And the ultraviolet light is at a very precise wavelength,

And let's see what happens when he shines it

he's warmed the mercury a bit, but it's not very warm.

Probably less than 100 degrees Centigrade

like a cup of tea, or something like that.

which contains a dye to make it look white.

and gives out a sort of purplish color of light.

So that's why the piece of paper that Neil is holding

Not very much, but the mercury atoms in the vapour

can absorb precisely the same wavelength of light

So it acts as a very precise and powerful filter

for the light. So the paper doesn't glow as brightly.

And you can see these clouds of swirling vapour.

And that's why liquid mercury is dangerous.

Because, all the time, vapour is coming off.

And mercury is one of the elements which can accumulate

So even if the mercury is coming off slowly

And there's stories of old lab buildings, where

they used to use mercury, where, when they're doing

the refurbishment, they lift the floorboards

which have fallen through when people have spilled it

there is quite a high level of mercury vapour

Though, usually, it's so dirty under the floor

that there's this layer of dust which prevents most of it coming off.

with this is that if you're using mercury,

and there are all sorts of experiments where it's useful

to use mercury, you must use it in a fume hood

that's well ventilated, so you don't breathe the vapour.

What's interesting is that, as it goes into the liquid nitrogen,

the nitrogen boils, and so the mercury falls

almost encased in this sort of bubble of nitrogen gas.

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水銀蒸気を見る - 動画の周期律表 (Looking at Mercury Vapour - Periodic Table of Videos)

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