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So now I'm going to show you Raman's collection of minerals
Lots of people had collections of minerals but his is special because he collected them all personally
And so ... brought them back here
So there is his own character, if you like, in his choice of things that he collected
Let's go and see some of them
There's a bewildering number of things to see
And one of the first things which is really very special is over here
When Raman first moved into this institute, there was no electricity
So he had this special device to reflect the Sun off this mirror into the room
As you know the Sun moves around as the time of day
But there's a special clock here and a system of levers
so that as the Sun moves, the mirror moves to keep the sun shining into the room
So let's go look at some of the samples
I'll just show you a few ... whichever ones look really interesting
So he looks really wise
These are interesting pearls which come from oysters as you know
Raman was very interested in the scattering of light
And the silvery color of pearls is due to the scattering of light between the layers of calcium carbonate that's laid down in the pearl
Here there are all sorts of gemstones
…and, Jade from China, samples from Brazil
He traveled all over the world
Quartz, silicon dioxide (SiO2), which contains inside it some liquid that was trapped during the geological process
Using light, which can shine through this he could find out what the liquid was without damaging the crystal
and he showed that the liquid was water with a mixture of carbon dioxide and methane
So, if you think about it it's really quite clever
Without damaging the crystal, you can find out what's inside
There's a really nice story about this piece of quartz
He got it from a farmer who brought it to sell it to him
And he bought it and then discovered about the liquid afterwards
Otherwise, the farmer would've probably ask for a lot more money
Here there are opals
Again the color is due to the scattering of light...
...something that fascinated Raman
Over here, there are some things which are very interesting but actually rather ordinary stuff
So up here are these really nice crystals
And they’re sugar!
Normally we see tiny crystals of sugar
I've never seen such big crystals of sugar in my life
I've got quite small hands but they’re still quite big
And even bigger down here are two salt crystals
These are natural salt crystals that Raman collected from a salt mine in Poland
And up here there are rather nice crystals of copper sulfate
Over here we have some nice samples of sulfur
I've got a small sample at home but it doesn't look anything as beautiful as this
And presumably this came from somewhere volcanic
And these samples here have a specially interesting story
These are artificial crystals
Apparently, there was a power cut - the electricity went off for several days
And not far from here there is a steelworks or, there was, where they made steel continuously in very hot furnaces
But when the electricity stopped, Raman realized that the furnaces would stop and there might be good crystals there
So he rushed off
and before they could start up the furnaces again he got these really nice crystals of carborundum
So now I want to show you the thing that I find the most moving in the whole of this display
Over here are two stones that come from the center of Hiroshima, the city that was attacked with the first-ever atom bomb
And these are pieces of mineral that have melted
The melting point is about 1800 degrees centigrade
And they apparently melted in the center of Hiroshima
Raman was given these pieces of stone by the city of Hiroshima in recognition of his active opposition of the use of nuclear weapons
But he was quite careful
and he said send them to me
and he had them tested for radioactivity before he added them to his collection
In here, we have series of samples of rock that don't look particularly special
but above them are some UV lamps
and if we switch out the light with the visible light
then suddenly, you see something really quite interesting
that all these minerals begin to glow
And they glow because they are absorbing UV light and then some of the energy is lost inside the crystal structure and they emit visible light
In here's some Ruby
and the large lump in the middle is artificial synthetic Ruby and the little bits round about are natural Ruby
and you can see that the natural Ruby fluoresces very nicely whereas the artificial stuff doesn't
This sample here is interesting ... something I've never seen
This rather grey mineral is called crocidolite and it is what asbestos is made from
You've probably heard that asbestos fibers - these very fine fibers - that were used for insulation can be breathed in and cause cancer
This sample is what asbestos is made from
And because it's dangerous, I'm not going to pick it up
Just as we were going, Shashi, who is the curator of this museum, produced another treasure for us
These are natural diamonds for optical windows which give you very strong windows that you can use for high pressure vessels and so on
And look at the size ... it's amazing!
I've seen diamond windows before but never seen natural ones of this size
These are natural diamonds which have been chopped to give you a slice of this
So the actual diamond itself must have been very much bigger
and diamonds of that size are extremely valuable
[Raman’s Nobel Prize] So this is the citation and here, as you can perhaps guess, is the medal
[Raman’s Spectroscope] Whenever he saw something interesting - a flower, a rock, whatever, he could look through this and see the spectrum
[Objectivity] Hello everyone! Welcome back to objectivity!
[Objectivity] Of course I'm wearing gloves
[Objectivity] But you know we mean business today because Keith is wearing gloves!
[Objectivity] Wow!


Diamonds, Pearls and Atomic Bomb Stones - Periodic Table of Videos

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林宜悉 發佈於 2020 年 3 月 28 日
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