Browse content similar to Earth: The Philosopher's Stone. Check below for episodes and series from the same categories and more!
Line | From | To | |
---|---|---|---|
Gold. This is what alchemists' dreams were made of. | 0:00:02 | 0:00:05 | |
The medieval thinkers spent their lives trying to find a way | 0:00:05 | 0:00:09 | |
to turn cheap metals, such as this lead, into gold. | 0:00:09 | 0:00:13 | |
Success would bring them fame and infinite fortune, | 0:00:15 | 0:00:18 | |
but is such magic even possible? | 0:00:18 | 0:00:21 | |
Join us in the search for the philosopher's stone. | 0:00:21 | 0:00:24 | |
APPLAUSE | 0:00:45 | 0:00:48 | |
The alchemists were obsessed with the idea of producing | 0:01:01 | 0:01:05 | |
a philosopher's stone. | 0:01:05 | 0:01:06 | |
A magical rock or powder that could turn metals into gold. | 0:01:06 | 0:01:11 | |
There are even stories of espionage, kidnap and even murder | 0:01:11 | 0:01:15 | |
in a bid to steal the secret of the stone. | 0:01:15 | 0:01:18 | |
But what about the gold I just made? | 0:01:18 | 0:01:20 | |
Well, I'm afraid we cheated. | 0:01:22 | 0:01:24 | |
I'm not an alchemist. My name is Dr Peter Wothers | 0:01:24 | 0:01:27 | |
and I'm a chemist from the University of Cambridge. | 0:01:27 | 0:01:31 | |
I did start with lead. | 0:01:31 | 0:01:33 | |
It was a specially prepared form of lead that reacts | 0:01:33 | 0:01:36 | |
with the oxygen from the air to give this beautiful lead oxide. | 0:01:36 | 0:01:41 | |
This yellowy orange compound here. | 0:01:41 | 0:01:43 | |
So we did cheat here. | 0:01:43 | 0:01:46 | |
And my philosopher's stone, well, | 0:01:46 | 0:01:48 | |
it was just a hot coal which started this reaction. | 0:01:48 | 0:01:52 | |
Some alchemists used this reaction to try to convince people | 0:01:52 | 0:01:56 | |
that they could make gold. But is such a feat even possible? | 0:01:56 | 0:02:00 | |
In the last of this year's Royal Institution Christmas lectures, | 0:02:00 | 0:02:03 | |
I hope to find out. | 0:02:03 | 0:02:05 | |
In the previous lectures, | 0:02:05 | 0:02:07 | |
we've looked at the elements in the air, and water, and now we are | 0:02:07 | 0:02:10 | |
going to look at the elements in the earth and how we can extract them. | 0:02:10 | 0:02:13 | |
How we can use them and whether we can turn one into another. | 0:02:13 | 0:02:17 | |
To help me, I have a giant periodic table made up | 0:02:17 | 0:02:20 | |
of members from the audience here at the Royal Institution. | 0:02:20 | 0:02:24 | |
Let's just look at the elements we have already talked about. | 0:02:24 | 0:02:28 | |
We have lead, can you stand up, please, lead? Thank you. | 0:02:28 | 0:02:30 | |
We were looking at you | 0:02:30 | 0:02:32 | |
and you were reacting with the oxygen from the air. | 0:02:32 | 0:02:34 | |
Can you stand up please, oxygen? OK. | 0:02:34 | 0:02:37 | |
This is how we normally find our metals in the earth. | 0:02:37 | 0:02:42 | |
We don't find them lying around, | 0:02:42 | 0:02:44 | |
they are normally combined with the oxygen from the air. | 0:02:44 | 0:02:47 | |
Or maybe sulphur, or occasionally other metals. Thank you very much. | 0:02:47 | 0:02:51 | |
If we put our periodic tables down now, please. | 0:02:51 | 0:02:54 | |
But occasionally, we can find metals just lying around. | 0:02:54 | 0:02:58 | |
The classic case is gold. Where are you, gold? | 0:02:58 | 0:03:02 | |
You are so special because sometimes you can be found just lying around. | 0:03:02 | 0:03:08 | |
In fact, here's a piece of you here. This is a gold nugget. | 0:03:08 | 0:03:14 | |
Thank you, periodic table, at ease. | 0:03:14 | 0:03:16 | |
This is pure gold. And it can be found like this in nature. | 0:03:16 | 0:03:20 | |
In fact, this is how it is normally found. | 0:03:20 | 0:03:23 | |
Now the remarkable thing about gold is that it doesn't change over time. | 0:03:23 | 0:03:27 | |
So you could leave it for tens, hundreds, even thousands | 0:03:27 | 0:03:31 | |
of years and it'll still have this beautiful appearance. | 0:03:31 | 0:03:36 | |
I've got a very old piece of gold to show you now. | 0:03:36 | 0:03:39 | |
Would you please welcome, from the Museum of London, Meriel Jeater. | 0:03:39 | 0:03:44 | |
APPLAUSE | 0:03:44 | 0:03:46 | |
I gather that this is a piece of local gold, is that right? | 0:03:51 | 0:03:55 | |
Exactly, yes. It was found in London, in Cannon Street in 1976. | 0:03:55 | 0:03:59 | |
-It's actually a Roman gold and emerald necklace. -That's beautiful. | 0:03:59 | 0:04:03 | |
This is pure gold wire running through these emeralds? | 0:04:03 | 0:04:06 | |
-That's right, yes. -And you say this is from the early Roman times? | 0:04:06 | 0:04:10 | |
-This is how old? -Nearly 2,000 years old, yes. -2,000 years old. | 0:04:10 | 0:04:14 | |
Has this been heavily restored? | 0:04:14 | 0:04:16 | |
It's been given a bit of a clean to get the mud off. | 0:04:16 | 0:04:19 | |
-Just the mud off and the gold itself was looking just like this? -Exactly. | 0:04:19 | 0:04:23 | |
-That's why it's so wonderful for archaeologists. -Exactly. | 0:04:23 | 0:04:26 | |
For me as a chemist, I think it's incredible that you can find | 0:04:26 | 0:04:29 | |
gold in this state and it doesn't tarnish over time. | 0:04:29 | 0:04:31 | |
It doesn't combine with oxygen or water or anything. | 0:04:31 | 0:04:33 | |
This is how you find it. | 0:04:33 | 0:04:35 | |
You can see that clearly it was highly prized | 0:04:35 | 0:04:37 | |
and I think maybe you should take it back to the museum. | 0:04:37 | 0:04:40 | |
-Thank you very much. -Pleasure. -Big round of applause, please. | 0:04:40 | 0:04:42 | |
APPLAUSE | 0:04:42 | 0:04:44 | |
This has lasted so well because it was so highly prized, | 0:04:47 | 0:04:51 | |
so valued there but also because it didn't change over time. | 0:04:51 | 0:04:55 | |
But, of course, we have a saying about the value of gold. | 0:04:55 | 0:04:58 | |
Sometimes people are told, "You're worth your weight in gold." | 0:04:58 | 0:05:02 | |
-Have you ever been told you're worth your weight in gold? -Yeah. | 0:05:02 | 0:05:05 | |
Oh, you have! Oh, good. Who told you that? | 0:05:05 | 0:05:07 | |
-I can't remember. -Probably a parent. | 0:05:07 | 0:05:09 | |
Maybe we should ask gold. Where's gold sitting? Are you gold, yes? | 0:05:09 | 0:05:13 | |
Have you been told that you're worth your weight in gold before? | 0:05:13 | 0:05:17 | |
-I think my parents... -They've told you this, have they? | 0:05:17 | 0:05:20 | |
I think we should see just how much gold that would be. | 0:05:20 | 0:05:24 | |
Would you like to come down to the front, please? | 0:05:24 | 0:05:26 | |
APPLAUSE | 0:05:26 | 0:05:29 | |
Would you like to face the front here. | 0:05:30 | 0:05:32 | |
-Would you like to tell everyone your name? -Emma. | 0:05:32 | 0:05:34 | |
Take a seat on here. | 0:05:34 | 0:05:35 | |
If you just carefully sit down on there. That's beautiful, lovely job. | 0:05:35 | 0:05:38 | |
OK, right, are you sitting comfortably? | 0:05:38 | 0:05:41 | |
-Yep. -Then we'll begin. This is where I get very excited. | 0:05:41 | 0:05:44 | |
This is all real gold. And it's pretty good stuff, actually. | 0:05:44 | 0:05:51 | |
Have you ever held a big block of gold before? | 0:05:51 | 0:05:54 | |
-No. -No. Well, have a feel of this. | 0:05:54 | 0:05:56 | |
That is pretty exciting, isn't it? Would you like to feel this as well? | 0:05:57 | 0:06:00 | |
I'm afraid I can't let everybody have... | 0:06:00 | 0:06:02 | |
I know, it's amazing, isn't it? | 0:06:02 | 0:06:04 | |
This is actually about the same as six large bottles of fizzy pop. | 0:06:04 | 0:06:09 | |
I'm just going to put this on here. | 0:06:09 | 0:06:12 | |
OK, I think you need more than that. Let's keep going. | 0:06:14 | 0:06:17 | |
Let's put this one on. It really is pretty good stuff, this. | 0:06:17 | 0:06:20 | |
This is 24ct pure gold. | 0:06:22 | 0:06:25 | |
And this one here. | 0:06:25 | 0:06:27 | |
More. More still. | 0:06:28 | 0:06:30 | |
Not quite. No. OK, let's try this one. | 0:06:33 | 0:06:37 | |
I think it's almost level but not quite. | 0:06:43 | 0:06:45 | |
I think we need just a little bit more. | 0:06:45 | 0:06:48 | |
Has anyone else in the audience got any gold? | 0:06:48 | 0:06:51 | |
LAUGHTER | 0:06:51 | 0:06:53 | |
I found some on the way in. | 0:06:53 | 0:06:56 | |
Oh, you've got some? | 0:06:56 | 0:06:57 | |
Isn't that Nobel prize-winning chemist Prof Sir Harry Kroto? | 0:06:57 | 0:07:01 | |
I think it is. | 0:07:01 | 0:07:03 | |
APPLAUSE | 0:07:03 | 0:07:05 | |
So what exactly...I think I might know what this is. | 0:07:13 | 0:07:16 | |
-Is this really your Nobel Prize? -Yes, they give them away. | 0:07:16 | 0:07:21 | |
-This is solid gold, isn't it? -It's solid gold. And I want it back. | 0:07:21 | 0:07:26 | |
-Well, of course, Harry. -I trust you. -Oh, thank you. | 0:07:26 | 0:07:31 | |
Right, anyway, maybe this is just what we need. | 0:07:31 | 0:07:34 | |
Let's just try that on there. | 0:07:34 | 0:07:36 | |
Oh, I think that's pretty well balanced now. | 0:07:38 | 0:07:41 | |
I think that's quite amazing. | 0:07:41 | 0:07:42 | |
I think that is 43kg of gold and one Nobel Prize. | 0:07:42 | 0:07:47 | |
Thank you very much. Big round of applause. | 0:07:47 | 0:07:50 | |
Stay where you are for a moment. | 0:07:50 | 0:07:52 | |
APPLAUSE | 0:07:52 | 0:07:54 | |
Thank you, Prof Kroto, for saving the day. This is quite amazing. | 0:07:54 | 0:07:58 | |
43kg, but it doesn't actually look too much there, does it, Emma? | 0:07:58 | 0:08:01 | |
What do you think? | 0:08:01 | 0:08:03 | |
As you say, it's very dense | 0:08:03 | 0:08:05 | |
and this is why it doesn't actually take up much space. | 0:08:05 | 0:08:08 | |
If you were made of gold, you would weigh 800kg, | 0:08:08 | 0:08:12 | |
which is about as much as a small car. | 0:08:12 | 0:08:15 | |
Which is quite a lot really, isn't it? So that's pretty impressive. | 0:08:15 | 0:08:19 | |
How much do you think this is worth? How much do you think? Have a guess. | 0:08:19 | 0:08:22 | |
Um...quite a lot. | 0:08:22 | 0:08:25 | |
I think you're right there. Quite a lot, yes. | 0:08:25 | 0:08:28 | |
Anyone have any other ideas? Shout it out. Yes? | 0:08:28 | 0:08:31 | |
-One million? -One million, actually, you're not far off. | 0:08:31 | 0:08:34 | |
It is even more than that. | 0:08:34 | 0:08:36 | |
This is about £1.5 million worth of gold just sitting here. | 0:08:36 | 0:08:41 | |
Which is pretty impressive, isn't it? All right, now. | 0:08:41 | 0:08:45 | |
If you just stay where you are sitting, please. | 0:08:45 | 0:08:47 | |
I need to unload this first of all. I'll just take that and... | 0:08:47 | 0:08:51 | |
LAUGHTER | 0:08:51 | 0:08:53 | |
Just going to put these over here. | 0:08:53 | 0:08:56 | |
A few little bits left. | 0:08:59 | 0:09:01 | |
There we are. That's fantastic. OK, thank you very much, Emma. | 0:09:02 | 0:09:06 | |
Big round of applause. | 0:09:06 | 0:09:07 | |
APPLAUSE | 0:09:07 | 0:09:09 | |
Gold really is an incredibly dense substance. | 0:09:14 | 0:09:18 | |
But actually, it's not the densest element. | 0:09:18 | 0:09:21 | |
Could we just have cards up for a second, please? | 0:09:21 | 0:09:24 | |
That honour goes to osmium. You are the densest thing in the universe. | 0:09:24 | 0:09:30 | |
Well, at least on Earth. Did you know that? | 0:09:30 | 0:09:33 | |
I don't mean that in a bad way. This is just you as an element. | 0:09:33 | 0:09:36 | |
Osmium is incredibly dense indeed. | 0:09:36 | 0:09:38 | |
Can we just keep the cards up for the people in the same row | 0:09:38 | 0:09:41 | |
as osmium and gold. Everyone else down. | 0:09:41 | 0:09:44 | |
Caesium stay up, barium stay up. All the way over to mercury. | 0:09:44 | 0:09:48 | |
Why is it, then, that these elements are so incredibly dense? | 0:09:48 | 0:09:53 | |
The most dense element is osmium, closely followed by iridium. | 0:09:53 | 0:09:57 | |
Well, atoms after osmium, iridium, gold, | 0:09:57 | 0:10:00 | |
all these other ones are getting heavier. | 0:10:00 | 0:10:02 | |
So the atoms themselves are heavier | 0:10:02 | 0:10:04 | |
and yet these ones are the most tightly packed. | 0:10:04 | 0:10:07 | |
So it's not just to do with how heavy the atoms are. | 0:10:07 | 0:10:10 | |
We also need to look at the bonding that we have between them. | 0:10:10 | 0:10:13 | |
And this is what we can see in the graph here. | 0:10:13 | 0:10:16 | |
This shows how much energy we need to put in to separate | 0:10:16 | 0:10:19 | |
a certain number of atoms of these elements. | 0:10:19 | 0:10:22 | |
And we see that we've got a peak around tungsten. | 0:10:22 | 0:10:26 | |
This is why we use tungsten in light bulb filaments, | 0:10:26 | 0:10:29 | |
because it's very difficult to pull them apart. | 0:10:29 | 0:10:31 | |
And we have very high temperatures. | 0:10:31 | 0:10:33 | |
But as we go beyond tungsten, the bonding isn't quite so strong | 0:10:33 | 0:10:37 | |
but the atoms are getting heavier. | 0:10:37 | 0:10:39 | |
And so it's bit of a balance between the strength of the bonds, | 0:10:39 | 0:10:43 | |
how tightly they are packed, and how heavy the atoms are. | 0:10:43 | 0:10:46 | |
This is why we reach a maximum for osmium and iridium. | 0:10:46 | 0:10:50 | |
Gold, platinum and so on are still very dense afterwards, | 0:10:50 | 0:10:54 | |
but the maximum is there for osmium and iridium. | 0:10:54 | 0:10:57 | |
So osmium is even more expensive than gold, in fact. | 0:10:57 | 0:11:00 | |
And if someone was really going to pay you a compliment | 0:11:00 | 0:11:03 | |
they would say, "You are worth your weight in osmium." | 0:11:03 | 0:11:07 | |
Actually, these metals are not the only precious things | 0:11:07 | 0:11:11 | |
we can extract from the earth. | 0:11:11 | 0:11:13 | |
There are even non-metals that we can sometimes find as well. | 0:11:13 | 0:11:17 | |
Hello. Hello, Prof Kroto. | 0:11:17 | 0:11:20 | |
I'm assuming you would like your Nobel Prize, would you? | 0:11:20 | 0:11:24 | |
-I'd swap it for those bigger ones. -Yes, so would I, I think. | 0:11:24 | 0:11:28 | |
Well, there we go. Thank you very much. | 0:11:28 | 0:11:31 | |
Perhaps you could tell us what you won the Nobel Prize for. | 0:11:31 | 0:11:35 | |
It's for discovering an alternative to these. | 0:11:35 | 0:11:39 | |
This is graphite and this is diamond. These structures. | 0:11:39 | 0:11:42 | |
These are actually the only ones that I knew about | 0:11:42 | 0:11:45 | |
when I was at school. | 0:11:45 | 0:11:46 | |
In the text books, there were just two types of carbon. | 0:11:46 | 0:11:49 | |
Two different forms called allotropes. | 0:11:49 | 0:11:51 | |
One has this arrangement. This one is the graphite. | 0:11:51 | 0:11:53 | |
This is the sort of thing you find in your pencils. | 0:11:53 | 0:11:56 | |
It's pretty soft and well, carbon, it's just an arrangement of carbon. | 0:11:56 | 0:11:59 | |
Diamond looks very different though, doesn't it? | 0:11:59 | 0:12:02 | |
I don't suppose...you've very kindly lent us your gold, | 0:12:02 | 0:12:05 | |
I don't suppose you have a spare diamond on you, do you? | 0:12:05 | 0:12:08 | |
I don't myself but my wife actually has one. | 0:12:08 | 0:12:11 | |
-A-ha! -You don't want to take that as well, do you? -Well, just borrow it. | 0:12:11 | 0:12:15 | |
-I hope I get it back. -Thank you, Mrs Kroto. Of course, yes. | 0:12:19 | 0:12:21 | |
You can trust me. | 0:12:21 | 0:12:24 | |
This is a beautiful ring here. Is it an engagement ring or something? | 0:12:24 | 0:12:30 | |
It's really quite lovely. | 0:12:30 | 0:12:32 | |
The diamond comes out quite easily, doesn't it? Yes. | 0:12:32 | 0:12:34 | |
LAUGHTER | 0:12:34 | 0:12:35 | |
We can see it more clearly now. Look at that. It's beautiful. | 0:12:35 | 0:12:38 | |
What a beautiful diamond. It is a real diamond though, is it? | 0:12:38 | 0:12:42 | |
-It as real as you can get. -It's quite stunning. | 0:12:42 | 0:12:46 | |
Of course, we want to show that this graphite is made up of carbon. | 0:12:46 | 0:12:52 | |
There is one way we can do this. | 0:12:52 | 0:12:53 | |
We can burn our carbon in oxygen and we'll get, what would we get? | 0:12:53 | 0:12:57 | |
-Carbon dioxide. -See? He's pretty good. Carbon dioxide. | 0:12:57 | 0:13:01 | |
-And then if we bubble that through lime water? -Calcium carbonate. | 0:13:01 | 0:13:05 | |
Calcium carbonate. That's the test for carbon dioxide, of course. | 0:13:05 | 0:13:08 | |
-And it would be white. -I didn't ask you that one. | 0:13:08 | 0:13:10 | |
You are getting carried away now. Let's just see this over here. | 0:13:10 | 0:13:14 | |
We have some apparatus. | 0:13:14 | 0:13:16 | |
This is where we are going to burn some graphite | 0:13:16 | 0:13:19 | |
and show that it is made of carbon. | 0:13:19 | 0:13:22 | |
What's bubbling through here is just oxygen. | 0:13:22 | 0:13:25 | |
This won't react with our lime water at all. | 0:13:25 | 0:13:28 | |
We are going to see if we can light the graphite | 0:13:28 | 0:13:32 | |
and get it burning inside the oxygen. There we are. Thank you. | 0:13:32 | 0:13:37 | |
That's great. So now we have a hydrogen flame. | 0:13:37 | 0:13:40 | |
This won't produce anything. It's only going to produce water. | 0:13:40 | 0:13:44 | |
You can see the water just beginning to condense. | 0:13:44 | 0:13:47 | |
Beautiful. I'm going to turn the flame off. | 0:13:47 | 0:13:50 | |
-Look at that. What do you think? -It's brilliant. | 0:13:52 | 0:13:54 | |
It is literally brilliant, yes. | 0:13:54 | 0:13:56 | |
This is the carbon combining with oxygen that's flowing through here. | 0:13:56 | 0:14:02 | |
Hopefully, we are going to see this changing colour, giving us | 0:14:02 | 0:14:06 | |
a milky colour. Showing that there is carbon dioxide present. | 0:14:06 | 0:14:09 | |
I think we should test diamond as well, don't you? What do you think? | 0:14:09 | 0:14:13 | |
ALL: Yes! | 0:14:13 | 0:14:14 | |
Yes? Does Mrs Kroto mind? | 0:14:14 | 0:14:17 | |
-OK. -In the name of science. That's very kind of you. | 0:14:17 | 0:14:20 | |
Harry seems a little nervous. Are you sure this is a real diamond? | 0:14:20 | 0:14:23 | |
-I think it's a real diamond, yes. -Let's give it a go then. | 0:14:23 | 0:14:27 | |
We will just put it on there. And again, we'll put this on here. | 0:14:27 | 0:14:31 | |
Right, so we have our flame. Here we go. The moment of truth. | 0:14:33 | 0:14:38 | |
Now can we get our diamond to burn in the oxygen? | 0:14:38 | 0:14:44 | |
WATER BUBBLES | 0:14:45 | 0:14:47 | |
Ah, look at that! | 0:14:54 | 0:14:57 | |
I hope you can afford to pay for this. | 0:14:57 | 0:14:59 | |
The good news is, Harry, it is a real diamond. | 0:14:59 | 0:15:02 | |
LAUGHTER | 0:15:02 | 0:15:04 | |
OK. | 0:15:04 | 0:15:05 | |
I think this is absolutely stunning. | 0:15:06 | 0:15:08 | |
That diamond there, it is burning in oxygen. | 0:15:08 | 0:15:13 | |
It's combining with the oxygen of the air. | 0:15:13 | 0:15:15 | |
-Have you ever seen a diamond burning like that before? -No, I haven't. | 0:15:15 | 0:15:18 | |
-It is quite stunning to see. -That's right. | 0:15:18 | 0:15:20 | |
There are no flames coming from this. | 0:15:20 | 0:15:23 | |
So this is just the heat of the reaction as the carbon combines | 0:15:23 | 0:15:28 | |
with the oxygen that's present, flowing through here, | 0:15:28 | 0:15:31 | |
forming carbon dioxide. That is absolutely stunning. | 0:15:31 | 0:15:35 | |
Just look at that. It's glowing all by itself. | 0:15:35 | 0:15:37 | |
It's absolutely brilliant. I think that's amazing. | 0:15:37 | 0:15:40 | |
And look, our lime water is going milky. | 0:15:40 | 0:15:44 | |
It's the most expensive lime water I've ever seen. | 0:15:44 | 0:15:48 | |
I think you are probably right there. | 0:15:48 | 0:15:50 | |
It really is the most expensive lime water you've ever seen. | 0:15:50 | 0:15:53 | |
-Well, we are waiting for your diamond just to... -Disappear. | 0:15:53 | 0:15:57 | |
To disappear, yes. | 0:15:57 | 0:15:59 | |
Maybe you could tell us about your Nobel Prize again. | 0:15:59 | 0:16:02 | |
-I think it has something to do with this. -I think it does, yes. | 0:16:02 | 0:16:06 | |
Would you like to come round to the front, actually. | 0:16:06 | 0:16:09 | |
We'll compare it to these ones. | 0:16:09 | 0:16:10 | |
This one was the graphite. This is the diamond. | 0:16:10 | 0:16:14 | |
And this is the third form, the well-characterised form. | 0:16:14 | 0:16:18 | |
It consists of 60 carbon atoms in the shape of a soccer ball. | 0:16:18 | 0:16:22 | |
And it was such a fantastic surprise when we discovered it. | 0:16:22 | 0:16:26 | |
One of the clues to its structure was Mr Fuller's geodesic domes. | 0:16:26 | 0:16:31 | |
In Montreal, we had visited that. And I remembered it. | 0:16:31 | 0:16:35 | |
It was in a book of mine | 0:16:35 | 0:16:37 | |
and when we were trying to work out how a sheet of graphite like this, | 0:16:37 | 0:16:42 | |
or a graphing sheet, might close up, | 0:16:42 | 0:16:45 | |
what we discovered was, it could close up if it had 12 pentagons. | 0:16:45 | 0:16:50 | |
You cannot close a sheet of hexagons up. It won't close up. | 0:16:50 | 0:16:53 | |
But if you have 12 pentagons, it will. | 0:16:53 | 0:16:56 | |
And you are all familiar with that in the case of the normal | 0:16:56 | 0:16:59 | |
soccer ball with 12 black pentagons and 20 hexagons. | 0:16:59 | 0:17:04 | |
And that's the magic that Mr Fuller knew, and other people as well. | 0:17:04 | 0:17:08 | |
And I called it Buckminsterfullerene | 0:17:08 | 0:17:12 | |
because there are double bonds as there are in benzene. | 0:17:12 | 0:17:15 | |
So the "ene" ending was just a beautiful sort of ending | 0:17:15 | 0:17:19 | |
to a great name. | 0:17:19 | 0:17:21 | |
So since my time at school, the textbooks have to be rewritten | 0:17:21 | 0:17:25 | |
with a new form of carbon discovered by this chap here. | 0:17:25 | 0:17:29 | |
-And colleagues in the States. -And your co-workers in the States. | 0:17:29 | 0:17:33 | |
We should have another look at your diamond here. | 0:17:33 | 0:17:36 | |
It seems to have decreased in size. | 0:17:36 | 0:17:39 | |
I think we should come clean. | 0:17:39 | 0:17:41 | |
Don't worry, we didn't destroy Mrs Kroto's engagement ring. | 0:17:41 | 0:17:45 | |
That really would be quite harsh. This is a pretty low-grade diamond. | 0:17:45 | 0:17:50 | |
It still looks pretty good to the naked eye | 0:17:50 | 0:17:53 | |
but the experts say it's not very valuable at all. | 0:17:53 | 0:17:55 | |
But it is a real diamond. | 0:17:55 | 0:17:57 | |
And it is combining with oxygen | 0:17:57 | 0:17:59 | |
and I think that's a pretty stunning reaction. Thank you, Prof Kroto. | 0:17:59 | 0:18:03 | |
It's a real privilege to have a Nobel Prize winner here, | 0:18:03 | 0:18:05 | |
helping out with an experiment. Thank you very much. | 0:18:05 | 0:18:08 | |
APPLAUSE | 0:18:08 | 0:18:09 | |
So is it possible that we could take this worthless carbon dioxide | 0:18:12 | 0:18:17 | |
and get our diamond back from that? | 0:18:17 | 0:18:20 | |
I mean, that really would be the alchemist's dream. | 0:18:20 | 0:18:23 | |
Recovering something precious from something worthless. | 0:18:23 | 0:18:26 | |
We've got a demonstration here that shows that this may be possible. | 0:18:26 | 0:18:30 | |
I'll just turn this round. | 0:18:30 | 0:18:32 | |
Now this tank is filled with carbon dioxide gas. | 0:18:34 | 0:18:38 | |
We've put some solid carbon dioxide in the bottom, | 0:18:38 | 0:18:41 | |
which is slowly evaporating, turning into the gas. | 0:18:41 | 0:18:44 | |
We can't see the gas because, of course, it's colourless. | 0:18:44 | 0:18:47 | |
But it is there. How can we test for this? | 0:18:47 | 0:18:50 | |
Does anyone know another use for carbon dioxide? Yes? | 0:18:50 | 0:18:53 | |
-To put out flames. -To put out flames, yes, exactly. | 0:18:53 | 0:18:55 | |
I wonder if we have a flame, please. Is there a flame anywhere? | 0:18:55 | 0:18:59 | |
Ah, yes. Here is a flame that certainly needs putting out. | 0:18:59 | 0:19:05 | |
If I just lower this into the tank... | 0:19:05 | 0:19:08 | |
There we are. You can see that it goes out. | 0:19:10 | 0:19:12 | |
This is because, of course, the tank is filled with carbon dioxide. | 0:19:12 | 0:19:16 | |
And carbon dioxide doesn't support combustion. | 0:19:16 | 0:19:19 | |
Right, now then. We have also placed in this tank some magnesium metal. | 0:19:20 | 0:19:27 | |
I'm just going to fish this out. | 0:19:27 | 0:19:29 | |
This is a little nest of magnesium metal. | 0:19:32 | 0:19:36 | |
I'm going to light the magnesium here | 0:19:36 | 0:19:38 | |
and it burns with a brilliant white flame. There we are. | 0:19:38 | 0:19:42 | |
Now I'm going to lower this into the carbon dioxide. | 0:19:42 | 0:19:46 | |
It seems to be burning even more vigorously now. | 0:19:46 | 0:19:49 | |
The flame is still burning. | 0:19:49 | 0:19:51 | |
But what about this? This one...well, this one still goes out. | 0:19:53 | 0:19:58 | |
Our petrol is extinguished in the carbon dioxide, | 0:19:59 | 0:20:04 | |
but the magnesium is reacting with it. | 0:20:04 | 0:20:07 | |
The magnesium is stealing the oxygen away from the carbon dioxide | 0:20:07 | 0:20:12 | |
and, well, we'll have a look at what we've got at the bottom | 0:20:12 | 0:20:15 | |
but let me take this out. You can see magnesium oxide | 0:20:15 | 0:20:18 | |
covered over what was the magnesium here, | 0:20:18 | 0:20:21 | |
but look in the centre. What we've now got is black carbon. | 0:20:21 | 0:20:26 | |
The magnesium removes the oxygen leaving behind the carbon | 0:20:28 | 0:20:32 | |
from the carbon dioxide. | 0:20:32 | 0:20:34 | |
We can get our carbon back from carbon dioxide | 0:20:34 | 0:20:38 | |
but, well, it's not a diamond yet. | 0:20:38 | 0:20:42 | |
Is it possible to turn that carbon into a diamond? | 0:20:42 | 0:20:47 | |
Well, actually, this is what happens deep within the earth, | 0:20:47 | 0:20:52 | |
and this is a diamond in a rock | 0:20:52 | 0:20:55 | |
just as it would have come out of the earth. | 0:20:55 | 0:21:00 | |
This is really quite beautiful indeed. | 0:21:00 | 0:21:02 | |
Deep within the earth, the carbon is heated up | 0:21:02 | 0:21:06 | |
and compressed with huge temperatures, huge pressures, | 0:21:06 | 0:21:09 | |
and the carbon we saw there, the black carbon, | 0:21:09 | 0:21:12 | |
is converted into diamond. | 0:21:12 | 0:21:16 | |
Recently, chemists have learnt how to copy this process, | 0:21:16 | 0:21:19 | |
how to turn graphite or other forms of carbon into diamond. | 0:21:19 | 0:21:24 | |
I'd like a volunteer to help me out with this one, please. | 0:21:24 | 0:21:28 | |
Would you like to come down to the front, please? | 0:21:28 | 0:21:32 | |
APPLAUSE | 0:21:32 | 0:21:34 | |
If you'd like to come down to the front. Your name is...? | 0:21:34 | 0:21:37 | |
-Lewis. -Lewis, OK. Now, this is a diamond. | 0:21:37 | 0:21:42 | |
Would you like to just hold this? | 0:21:42 | 0:21:45 | |
-What do you think, are you impressed? -Yeah. | 0:21:45 | 0:21:47 | |
Looks like a piece of glass, doesn't it? It actually really is a diamond. | 0:21:47 | 0:21:51 | |
This is a synthetically grown diamond and this has been prepared | 0:21:51 | 0:21:54 | |
not from the high temperature, high pressure system that we also use, | 0:21:54 | 0:21:58 | |
this is a technique called chemical vapour deposition | 0:21:58 | 0:22:01 | |
where the diamond is gradually built up a layer at a time. | 0:22:01 | 0:22:04 | |
I'd like you to take this, not keep it, but bring it over here | 0:22:04 | 0:22:08 | |
and just place it on top. | 0:22:08 | 0:22:10 | |
This is some ice here. Hold it like this. | 0:22:10 | 0:22:14 | |
Just put that on top of there and push through this ice. | 0:22:14 | 0:22:19 | |
-How does that feel? -Cold. -It feels very cold and what's happening? | 0:22:19 | 0:22:22 | |
Water's coming off. | 0:22:22 | 0:22:24 | |
This is ice, solid ice, and it seems to be going... | 0:22:24 | 0:22:28 | |
You've chopped all the way through this quite cleanly there. | 0:22:28 | 0:22:31 | |
As you say, it's got very cold. | 0:22:31 | 0:22:33 | |
-Do you know why it's got colder? -No idea. | 0:22:33 | 0:22:35 | |
It's used your energy to heat up this block of ice, | 0:22:35 | 0:22:38 | |
so yes, you're getting cold because it's taking the energy | 0:22:38 | 0:22:41 | |
from your fingers here. Let's try this again. | 0:22:41 | 0:22:44 | |
If I just put this on here, it slices through like butter. | 0:22:44 | 0:22:47 | |
It's really quite amazing. It feels very strange. | 0:22:47 | 0:22:50 | |
-I'm not sawing. -It's not cutting because it's hard, | 0:22:50 | 0:22:54 | |
it's cutting because it's a very good conductor of heat. | 0:22:54 | 0:22:57 | |
Quite remarkable, so cleanly through this block of ice. | 0:22:57 | 0:23:01 | |
Feels very strange. Thank you very much, thank you for that. | 0:23:01 | 0:23:04 | |
APPLAUSE | 0:23:04 | 0:23:07 | |
That remarkable property of diamond | 0:23:08 | 0:23:10 | |
was because it's an incredible conductor of heat. | 0:23:10 | 0:23:13 | |
To demonstrate this and explain why this is so, | 0:23:13 | 0:23:16 | |
I'd like some other volunteers, please. | 0:23:16 | 0:23:19 | |
I'd like six people so if we could have all of you, six of you, | 0:23:19 | 0:23:22 | |
if you could come down to the front, please? | 0:23:22 | 0:23:25 | |
In a row, facing the audience. Sit next to each other. | 0:23:25 | 0:23:30 | |
I'd like all of you to face that direction, please, | 0:23:30 | 0:23:33 | |
turn around and face that way. | 0:23:33 | 0:23:35 | |
Just close up a little bit, a little bit friendlier. | 0:23:35 | 0:23:38 | |
Come this way, please. Lovely job. Close up there | 0:23:38 | 0:23:41 | |
and put your hands on the shoulders of the person in front. | 0:23:41 | 0:23:45 | |
Face that way. That's good. | 0:23:45 | 0:23:47 | |
Now, at the moment, these are all pretty weak bonds here. | 0:23:47 | 0:23:50 | |
Watch what happens when I give a bit of energy this way. | 0:23:50 | 0:23:53 | |
Don't do anything, just behave normally. | 0:23:53 | 0:23:55 | |
Lucy, can you feel anything? | 0:23:55 | 0:23:58 | |
It was very difficult to get this energy through there | 0:23:58 | 0:24:01 | |
and this is because of all these weak bonds. | 0:24:01 | 0:24:04 | |
What I'd like you to do is just spread yourselves out a little more | 0:24:04 | 0:24:07 | |
and hold arms with very rigid arms. | 0:24:07 | 0:24:10 | |
Rigid, straight arms. That's it. | 0:24:10 | 0:24:13 | |
Now I'm just going to do the same thing again. | 0:24:13 | 0:24:16 | |
Give you a jolt that end and now you can see you're certainly moving. | 0:24:16 | 0:24:21 | |
Thank you very much indeed, thank you for all your help. | 0:24:21 | 0:24:25 | |
APPLAUSE | 0:24:25 | 0:24:27 | |
This is why our diamond is such a good conductor of thermal energy. | 0:24:27 | 0:24:33 | |
It's because the bonds are so strong holding these carbon atoms together, | 0:24:33 | 0:24:38 | |
they're so rigid, that this energy is very easily transmitted through. | 0:24:38 | 0:24:42 | |
Diamond is the best conductor of heat of any substance known, | 0:24:42 | 0:24:46 | |
until very recently when scientists discovered a new form of carbon, | 0:24:46 | 0:24:50 | |
another form, called graphene, which is a single sheet of graphite. | 0:24:50 | 0:24:54 | |
That is an even better conductor of heat. They're the best ones known. | 0:24:54 | 0:24:59 | |
We've seen then that we can convert charcoal, | 0:25:01 | 0:25:04 | |
we convert graphite into diamond under very high pressures | 0:25:04 | 0:25:08 | |
or using the other technique of chemical vapour deposition. | 0:25:08 | 0:25:11 | |
Surely if the alchemists had focused on that, they would have changed | 0:25:11 | 0:25:16 | |
their attention away from trying to turn base metals into gold. | 0:25:16 | 0:25:20 | |
But of course, they were focused on metals because metals | 0:25:20 | 0:25:23 | |
were incredibly important and still are very important. | 0:25:23 | 0:25:26 | |
It's only gold that has this unique property | 0:25:26 | 0:25:28 | |
that we can find it lying around. Most metals we find in their ores. | 0:25:28 | 0:25:33 | |
Ores like this here. | 0:25:33 | 0:25:35 | |
This is the natural mineral - does anybody know what it is? | 0:25:35 | 0:25:40 | |
It is an iron ore. | 0:25:40 | 0:25:42 | |
Does anyone know what the name of the iron ore would be? | 0:25:42 | 0:25:46 | |
Very good, you're doing well. Hematite it is. | 0:25:46 | 0:25:48 | |
This is the mineral hematite. | 0:25:48 | 0:25:51 | |
This is now our source for iron | 0:25:51 | 0:25:54 | |
but it's locked up with the iron combined with oxygen. | 0:25:54 | 0:25:59 | |
Somehow we have to learn how to extract the metal out of this. | 0:25:59 | 0:26:03 | |
After all, it doesn't just fall from the skies. | 0:26:03 | 0:26:06 | |
But remarkably, sometimes it does just fall from the skies | 0:26:06 | 0:26:11 | |
and this is what we have here. | 0:26:11 | 0:26:14 | |
This is actually very heavy as well. | 0:26:14 | 0:26:17 | |
This is a lump of iron that did fall from the skies about 5,000 years ago | 0:26:17 | 0:26:22 | |
and it landed in Australia. Look at this. | 0:26:22 | 0:26:26 | |
What I wanted to show you here was the comparison | 0:26:26 | 0:26:29 | |
between these two pieces. | 0:26:29 | 0:26:31 | |
We can see that this is developing this reddish-brown colour, | 0:26:31 | 0:26:36 | |
the same as the hematite. | 0:26:36 | 0:26:39 | |
This contains iron. It is a slice of iron | 0:26:39 | 0:26:41 | |
but it is gradually combining with oxygen | 0:26:41 | 0:26:44 | |
to form this mineral hematite. | 0:26:44 | 0:26:46 | |
We can show that it is a meteorite | 0:26:46 | 0:26:49 | |
if we were to take a slice through this. | 0:26:49 | 0:26:52 | |
If we took a slice through this, | 0:26:52 | 0:26:55 | |
what we would see is something like this. | 0:26:55 | 0:26:58 | |
This is a slice through a meteorite and it's really quite beautiful. | 0:26:58 | 0:27:05 | |
This has been cut and we can see the side here. | 0:27:05 | 0:27:07 | |
This is the outer surface of the meteorite | 0:27:07 | 0:27:10 | |
and here it's been cut with this incredible pattern here. | 0:27:10 | 0:27:13 | |
This pattern has been etched with acid. | 0:27:13 | 0:27:17 | |
It etches away certain types of the minerals that are in here. | 0:27:17 | 0:27:21 | |
The forms of the iron, it etches away certain of them | 0:27:21 | 0:27:25 | |
and it reveals this beautiful crystal structure | 0:27:25 | 0:27:28 | |
and this proves that it's a meteorite, | 0:27:28 | 0:27:30 | |
because it's impossible to get this pattern here on Earth. | 0:27:30 | 0:27:34 | |
That's because we need to cool down molten iron | 0:27:34 | 0:27:36 | |
with a little bit of nickel in. | 0:27:36 | 0:27:38 | |
We'd need to cool it down over such a slow rate, | 0:27:38 | 0:27:41 | |
just one degree over thousands of years, | 0:27:41 | 0:27:44 | |
if we wanted to see these crystals develop. | 0:27:44 | 0:27:46 | |
This really is quite stunning indeed. | 0:27:46 | 0:27:50 | |
Over time, the metal of this beautiful meteorite | 0:27:50 | 0:27:55 | |
will turn into this ore here. | 0:27:55 | 0:27:58 | |
We can't wait thousands of years to see that | 0:27:58 | 0:28:00 | |
but we can speed this process up | 0:28:00 | 0:28:02 | |
and we can show how iron combines with the oxygen to form iron oxide. | 0:28:02 | 0:28:07 | |
I'd like a volunteer for this one, please. | 0:28:07 | 0:28:10 | |
I'd like someone from this side, who shall we have? | 0:28:10 | 0:28:12 | |
Would you like to come down to the front, please? | 0:28:12 | 0:28:15 | |
APPLAUSE | 0:28:15 | 0:28:18 | |
-Would you like to tell us your name, please? -Rose. | 0:28:18 | 0:28:21 | |
Rose, OK, we have some iron over here. This is just iron wool. | 0:28:21 | 0:28:24 | |
Would you like to feel this? | 0:28:24 | 0:28:26 | |
It's just the sort of thing you would use to clean your pots | 0:28:26 | 0:28:29 | |
and pans if you're helping out at home. | 0:28:29 | 0:28:31 | |
Now, I'll put on my goggles | 0:28:31 | 0:28:33 | |
and we're going to combine this with some oxygen. | 0:28:33 | 0:28:36 | |
We want to see how much this weighs by itself. This weighs 15.9 grams. | 0:28:36 | 0:28:42 | |
Now, the question is, what will happen | 0:28:42 | 0:28:44 | |
when this combines with the oxygen from the air? | 0:28:44 | 0:28:47 | |
How do you think its mass will change? | 0:28:47 | 0:28:49 | |
Will it go up, go down, stay the same? | 0:28:49 | 0:28:52 | |
What do you think, when it burns? | 0:28:52 | 0:28:54 | |
-It will go up? -It will go up, and why's that? | 0:28:54 | 0:28:56 | |
-Because it will become more dense. -It will become more dense. | 0:28:56 | 0:29:01 | |
Let's have a look and see, shall we? | 0:29:01 | 0:29:03 | |
I'm just going to apply a light here. | 0:29:03 | 0:29:05 | |
This beautiful reaction is the iron combining with the oxygen | 0:29:05 | 0:29:09 | |
and look what's happened to the mass. | 0:29:09 | 0:29:11 | |
It's gone down. It's getting lower. | 0:29:11 | 0:29:15 | |
-0.16, so whoever said it goes down, you're quite right. | 0:29:15 | 0:29:19 | |
But look now what's happening. It's going up again. | 0:29:19 | 0:29:22 | |
It's is getting heavier so whoever said it goes up, you're quite right. | 0:29:22 | 0:29:25 | |
Everyone's right, that's good. Why did it go down? | 0:29:25 | 0:29:28 | |
It went down initially because this iron wool was treated with oil, | 0:29:28 | 0:29:32 | |
just to try and stop it combining with the oxygen from the air. | 0:29:32 | 0:29:37 | |
Once this reaction has started, it is combining with oxygen | 0:29:37 | 0:29:40 | |
and that's why it's getting heavier. You were quite right. | 0:29:40 | 0:29:43 | |
It is getting heavier because the iron is forming iron oxide. | 0:29:43 | 0:29:47 | |
Thank you very much indeed. | 0:29:47 | 0:29:49 | |
APPLAUSE | 0:29:49 | 0:29:52 | |
Iron is pretty reactive stuff. | 0:29:54 | 0:29:56 | |
It reacts with oxygen and this is how | 0:29:56 | 0:29:58 | |
we would normally find our metal, combined with oxygen. | 0:29:58 | 0:30:02 | |
What about if you couldn't extract the iron from this? | 0:30:02 | 0:30:06 | |
What about before we knew how to do this? | 0:30:06 | 0:30:08 | |
The only iron that we would have had would have been iron | 0:30:08 | 0:30:11 | |
from a natural source such as this meteorite. | 0:30:11 | 0:30:14 | |
This sort of iron was used to make tools and so on. | 0:30:14 | 0:30:18 | |
I think we have an example of a tool using some natural iron here. | 0:30:18 | 0:30:22 | |
Would you please welcome Dr Caroline Smith | 0:30:22 | 0:30:24 | |
from the Natural History Museum. | 0:30:24 | 0:30:27 | |
APPLAUSE | 0:30:27 | 0:30:29 | |
This is really beautiful. What exactly is this? | 0:30:31 | 0:30:34 | |
This is an Inuit knife and it's made of walrus tusk, | 0:30:34 | 0:30:38 | |
so walrus ivory, but in the end you can hopefully see | 0:30:38 | 0:30:42 | |
it actually has an iron blade. | 0:30:42 | 0:30:45 | |
When this was discovered, the Inuits hadn't yet learnt | 0:30:45 | 0:30:48 | |
how to make iron, how to extract it from the ore. | 0:30:48 | 0:30:51 | |
That's right. They had to have a source of metallic iron. | 0:30:51 | 0:30:54 | |
At the time, it was thought that the iron in this knife | 0:30:54 | 0:30:57 | |
was actually from a meteorite called the Cape York meteorite, | 0:30:57 | 0:31:01 | |
a very large meteorite which was found in Greenland. | 0:31:01 | 0:31:04 | |
This knife actually came from Greenland, | 0:31:04 | 0:31:06 | |
but we're not actually sure that's right, now, | 0:31:06 | 0:31:09 | |
we think it might be from somewhere else. | 0:31:09 | 0:31:11 | |
I gather that you've performed an analysis on this | 0:31:11 | 0:31:14 | |
and more research suggests that you are beginning to question | 0:31:14 | 0:31:17 | |
whether this is a meteorite, but it has to be naturally occurring | 0:31:17 | 0:31:21 | |
because they didn't have the technology. | 0:31:21 | 0:31:23 | |
Exactly. They didn't have the technology to extract iron | 0:31:23 | 0:31:26 | |
from things like hematite so they had to have a source | 0:31:26 | 0:31:29 | |
of native iron, metallic iron. | 0:31:29 | 0:31:30 | |
We think now that maybe this is actually from a place | 0:31:30 | 0:31:33 | |
called Disko Island, | 0:31:33 | 0:31:35 | |
which is an island off the west coast of Greenland, | 0:31:35 | 0:31:37 | |
and it's one of the very few locations on earth | 0:31:37 | 0:31:41 | |
where you get metallic iron existing in metallic form. | 0:31:41 | 0:31:45 | |
You very kindly brought a couple of samples for us. | 0:31:45 | 0:31:48 | |
These are from Disko Island. | 0:31:48 | 0:31:51 | |
They look quite different but this one clearly looks very metallic. | 0:31:51 | 0:31:56 | |
You can see this here, it's got quite a shine to it. | 0:31:56 | 0:31:58 | |
-It's quite a heavy specimen. -It is very heavy. | 0:31:58 | 0:32:01 | |
This looks like a piece of iron but this is naturally occurring iron? | 0:32:01 | 0:32:05 | |
This is naturally occurring iron found at the surface of the Earth. | 0:32:05 | 0:32:08 | |
In fact, tons of this iron has been found. | 0:32:08 | 0:32:11 | |
But why hasn't this one corroded into the hematite? | 0:32:11 | 0:32:15 | |
What we think happened is that about 55 million years ago, | 0:32:15 | 0:32:18 | |
lava was erupted in this place, in Disko Island, | 0:32:18 | 0:32:21 | |
and as the lava was coming up, | 0:32:21 | 0:32:23 | |
it went through sedimentary rocks that have got a lot of carbon in, | 0:32:23 | 0:32:28 | |
and the lava picked the carbon up | 0:32:28 | 0:32:29 | |
and you've got a chemical reaction happening where the iron, | 0:32:29 | 0:32:33 | |
which was bonded with oxygen just like here in the hematite, | 0:32:33 | 0:32:36 | |
actually became metallic iron. It reduced the iron from the lava. | 0:32:36 | 0:32:40 | |
We can see this is also a sample of iron, so this is iron. | 0:32:40 | 0:32:44 | |
This is a sample of lava from Disko Island | 0:32:44 | 0:32:46 | |
so there is some metal in there but not as big as that. | 0:32:46 | 0:32:50 | |
This one is a very grey colour and that's due to the graphite | 0:32:50 | 0:32:53 | |
and carbon in here? | 0:32:53 | 0:32:55 | |
You can see a bit of a smudge on the paper. | 0:32:55 | 0:32:58 | |
There's a black smear there. | 0:32:58 | 0:33:00 | |
That's just from the carbon that's present in here, the graphite? | 0:33:00 | 0:33:03 | |
-That's right. -Actually, we've got a clip of a blast furnace to show. | 0:33:03 | 0:33:07 | |
This is how iron is now manufactured | 0:33:07 | 0:33:10 | |
and this is using carbon to steal away the oxygen from the iron ore, | 0:33:10 | 0:33:14 | |
from the hematite. | 0:33:14 | 0:33:16 | |
This is how we're producing iron but what you're saying now is that... | 0:33:16 | 0:33:19 | |
Nature beat us to it about 55 million years ago. | 0:33:19 | 0:33:22 | |
-Exactly. -That is quite amazing. | 0:33:22 | 0:33:24 | |
Thank you very much for bringing these samples on. | 0:33:24 | 0:33:29 | |
Now, I really wanted to produce some molten iron for you | 0:33:32 | 0:33:36 | |
here in the lecture theatre, but clearly we couldn't bring in | 0:33:36 | 0:33:39 | |
a blast furnace, so we had to think of another way to do this. | 0:33:39 | 0:33:42 | |
We can learn from what we did earlier, | 0:33:42 | 0:33:45 | |
when we used the magnesium metal to steal the oxygen away | 0:33:45 | 0:33:49 | |
from the carbon dioxide. | 0:33:49 | 0:33:51 | |
We can do the same thing now with our iron oxide. | 0:33:51 | 0:33:53 | |
We can use a more reactive metal | 0:33:53 | 0:33:56 | |
and we are going to use the metal, aluminium. | 0:33:56 | 0:33:59 | |
You may be wondering why there's a safe under here. | 0:33:59 | 0:34:04 | |
This is because we have a bit of an embarrassing story here. | 0:34:04 | 0:34:07 | |
We accidentally locked Andy's Christmas bonus in the safe. | 0:34:07 | 0:34:14 | |
We tried getting into the safe and it's pretty hard. | 0:34:14 | 0:34:17 | |
It's made of pretty solid stuff. We can't really get into this | 0:34:17 | 0:34:23 | |
but the energy generated as the oxygen is taken away | 0:34:23 | 0:34:27 | |
by the aluminium to form iron should be enough to get in here. | 0:34:27 | 0:34:32 | |
Can we have a little look in here? | 0:34:32 | 0:34:34 | |
Get the camera right in to show what's inside this vessel. | 0:34:34 | 0:34:37 | |
This is made of a very tough form of carbon. This is made of graphite, | 0:34:37 | 0:34:41 | |
and you may be able to see the orangey colour. | 0:34:41 | 0:34:44 | |
That's our iron oxide. It's mixed with aluminium powder. | 0:34:44 | 0:34:49 | |
The thing you see sticking out there is a little bit of magnesium | 0:34:49 | 0:34:52 | |
I'm going to use to start this reaction. | 0:34:52 | 0:34:54 | |
Hopefully, we should generate some iron | 0:34:54 | 0:34:57 | |
and see if we can get through into the safe. | 0:34:57 | 0:34:59 | |
-Sounds like a good idea, doesn't it? -If it's the only way to do it. | 0:34:59 | 0:35:03 | |
I think we will need a safety screen around this, though. | 0:35:03 | 0:35:08 | |
I'm going to need a glove as well. Thank you very much. | 0:35:08 | 0:35:14 | |
-Feeling confident? -Yeah, I can't see what could go wrong. | 0:35:14 | 0:35:17 | |
What could possibly go wrong? Exactly. | 0:35:17 | 0:35:20 | |
Let's give it a go. You'll see a bright white light first of all. | 0:35:20 | 0:35:23 | |
That's just the magnesium we saw earlier. | 0:35:23 | 0:35:25 | |
The magnesium combining with the oxygen from the air. | 0:35:25 | 0:35:28 | |
OK. We should know when it starts. I think it's started now! | 0:35:31 | 0:35:36 | |
This is our little blast furnace here. Look at that, fantastic. | 0:35:36 | 0:35:40 | |
We've got some molten metal there. Can we lose the safety screen? | 0:35:40 | 0:35:43 | |
That would be good if we can possibly take this off. Lovely job. | 0:35:43 | 0:35:47 | |
Right off the top very carefully. I'm just going to see... | 0:35:47 | 0:35:52 | |
I'll give you that, see if we can pick up this. | 0:35:52 | 0:35:56 | |
What have we got here? Yes, that's wonderful. | 0:35:56 | 0:35:59 | |
It releases such an enormous amount of energy | 0:35:59 | 0:36:02 | |
as the aluminium combines with the oxygen from the iron oxide. | 0:36:02 | 0:36:06 | |
Good news, Andy. Good news and bad news. | 0:36:06 | 0:36:08 | |
The good news is there's a hole in the top of the safe. | 0:36:08 | 0:36:12 | |
The bad news is there's a lot of smoke coming from outside. | 0:36:12 | 0:36:15 | |
I think I've just found the key as well! | 0:36:15 | 0:36:19 | |
Now he finds the key! At least we got into the safe, well done. | 0:36:19 | 0:36:22 | |
Thank you very much for that. | 0:36:22 | 0:36:25 | |
APPLAUSE | 0:36:25 | 0:36:27 | |
We formed there during that reaction aluminium oxide | 0:36:27 | 0:36:30 | |
as the aluminium took the oxygen away. | 0:36:30 | 0:36:33 | |
This is how we find aluminium in nature. | 0:36:33 | 0:36:35 | |
We find it as aluminium oxide and here's a sample here. | 0:36:35 | 0:36:39 | |
What do you think of that? | 0:36:39 | 0:36:42 | |
It is light and this is because it's a very light metal, aluminium. | 0:36:42 | 0:36:47 | |
How can we get our aluminium out of this rock? | 0:36:47 | 0:36:52 | |
This, for a long time, was a great problem. | 0:36:52 | 0:36:55 | |
It was only solved when chemists realised they could use | 0:36:55 | 0:36:59 | |
an even more reactive metal and this was the metal over here, | 0:36:59 | 0:37:03 | |
the metal potassium. | 0:37:03 | 0:37:05 | |
When this was first discovered, it was a bit of a curiosity. | 0:37:05 | 0:37:08 | |
There was this amazing substance, aluminium, | 0:37:08 | 0:37:10 | |
and it did have very remarkable properties. | 0:37:10 | 0:37:13 | |
I'll need another volunteer from the audience. | 0:37:13 | 0:37:15 | |
We'll have someone this side. | 0:37:15 | 0:37:17 | |
In the green, would you like to come down, please? | 0:37:17 | 0:37:20 | |
APPLAUSE | 0:37:20 | 0:37:22 | |
-Your name is? -Ailish. -Ailish, OK, great. | 0:37:25 | 0:37:29 | |
Obviously you've seen a lot of aluminium before, haven't you? | 0:37:29 | 0:37:32 | |
It's very cheap now because now we have worked out | 0:37:32 | 0:37:35 | |
how to extract it from the ores, but initially, | 0:37:35 | 0:37:37 | |
it was incredibly difficult and that made it incredibly expensive. | 0:37:37 | 0:37:41 | |
In fact, so valuable and so strange that this chap, | 0:37:41 | 0:37:45 | |
this is Napoleon III, | 0:37:45 | 0:37:47 | |
he had a whole cutlery set made from aluminium. | 0:37:47 | 0:37:50 | |
I think we have some aluminium utensils here | 0:37:50 | 0:37:53 | |
so you have a look at these. What do you think? | 0:37:53 | 0:37:56 | |
-Very light. -They are very light, aren't they? | 0:37:56 | 0:37:58 | |
This was the remarkable thing. | 0:37:58 | 0:37:59 | |
With Napoleon's cutlery set, he had his cutlery, | 0:37:59 | 0:38:03 | |
and it was so valuable that if he had a huge feast, | 0:38:03 | 0:38:05 | |
he would give his most honoured guests the aluminium cutlery | 0:38:05 | 0:38:09 | |
and all the rest had to make do with gold. | 0:38:09 | 0:38:12 | |
OK, it seems strange to us now | 0:38:12 | 0:38:14 | |
because we do know how to extract aluminium | 0:38:14 | 0:38:16 | |
and it is incredibly abundant and we can find loads of it around | 0:38:16 | 0:38:20 | |
but it was very difficult to get it out. | 0:38:20 | 0:38:22 | |
Can I just say, it does feel very light indeed. | 0:38:22 | 0:38:24 | |
That is one of the remarkable properties. | 0:38:24 | 0:38:27 | |
It isn't actually the lightest metal that's known. | 0:38:27 | 0:38:30 | |
-Do you know what the lightest metal is? -Lithium. | 0:38:30 | 0:38:34 | |
Oh, yes, you're quite right. It is lithium. Give us a wave, lithium! | 0:38:34 | 0:38:37 | |
Lithium is in fact a metal and it is incredibly light. | 0:38:37 | 0:38:41 | |
We have made the world's first lithium spoon, | 0:38:41 | 0:38:45 | |
which is very exciting. Here it is. | 0:38:45 | 0:38:49 | |
This is our special RI spoon. | 0:38:49 | 0:38:52 | |
Isn't that beautiful? Would you like to feel this? | 0:38:54 | 0:38:57 | |
-It's really light. -It really is. It's amazingly light. | 0:38:57 | 0:39:01 | |
It feels almost like plastic but it is solid metal. | 0:39:01 | 0:39:04 | |
It is quite remarkable, don't you think? | 0:39:04 | 0:39:07 | |
This is my dinner, I think. | 0:39:07 | 0:39:11 | |
Some soup. Of course, cutlery sinks in it, | 0:39:11 | 0:39:16 | |
but would you just drop it in and step back? | 0:39:16 | 0:39:21 | |
Look at that? First of all, | 0:39:21 | 0:39:23 | |
it is incredibly light and it's floating on the surface, | 0:39:23 | 0:39:26 | |
but it's also reacting. | 0:39:26 | 0:39:27 | |
I'm going to fish that out. It's very reactive indeed. | 0:39:27 | 0:39:31 | |
I don't think lithium spoons are going to catch on at all, do you? | 0:39:31 | 0:39:34 | |
-This is because it's just too reactive. -Too explosive. | 0:39:34 | 0:39:37 | |
Exactly, thank you very much indeed. | 0:39:37 | 0:39:40 | |
APPLAUSE | 0:39:40 | 0:39:43 | |
A bit of coughing there just from the reaction | 0:39:45 | 0:39:48 | |
as the lithium combines with the oxygen. | 0:39:48 | 0:39:51 | |
It's reacting with the water vapour. | 0:39:51 | 0:39:54 | |
COUGHING | 0:39:54 | 0:39:57 | |
Yes, yes. Thank you. The lithium there, it floats on the surface. | 0:39:57 | 0:40:03 | |
It is incredibly light but it's incredibly reactive as well. | 0:40:03 | 0:40:08 | |
That may be the world's first lithium spoon | 0:40:08 | 0:40:11 | |
but I think it's safe to say it's also going to be the world's last. | 0:40:11 | 0:40:15 | |
It does show how reactive lithium is and maybe be can use this element | 0:40:15 | 0:40:20 | |
to prepare new elements, and we can indeed. | 0:40:20 | 0:40:23 | |
We have a reaction here to generate a new element from silicon dioxide. | 0:40:23 | 0:40:29 | |
Does anyone know where we find silicon dioxide? | 0:40:29 | 0:40:33 | |
Any ideas, right at the back? | 0:40:33 | 0:40:36 | |
In sand, you're quite right. | 0:40:36 | 0:40:38 | |
We find silicon dioxide, it is sand. | 0:40:38 | 0:40:42 | |
We've got some lithium in here and some sand. | 0:40:44 | 0:40:47 | |
We've mixed the two together, little lithium pelts and some sand, | 0:40:47 | 0:40:51 | |
and I'm going to heat this up at the moment and see what happens. | 0:40:51 | 0:40:56 | |
This is lithium with silicon dioxide | 0:40:56 | 0:40:58 | |
and the silicon dioxide is a mineral, it's just sand. | 0:40:58 | 0:41:01 | |
Quartz is the same stuff, silicon dioxide, | 0:41:01 | 0:41:04 | |
so sand is smashed up pieces of quartz. | 0:41:04 | 0:41:08 | |
I'm hoping that we should see a reaction take place | 0:41:08 | 0:41:11 | |
and there we are. | 0:41:11 | 0:41:14 | |
This is a very violent reaction again | 0:41:14 | 0:41:17 | |
and this is as the lithium is stealing the oxygen away | 0:41:17 | 0:41:21 | |
from the silicon dioxide that makes up the sand. | 0:41:21 | 0:41:24 | |
Anyone have a guess at what we're going to make? Silicon, very good. | 0:41:26 | 0:41:30 | |
We take the oxygen away from the silicon dioxide | 0:41:30 | 0:41:34 | |
and we end up with silicon. | 0:41:34 | 0:41:38 | |
Remarkably, this is a single crystal | 0:41:38 | 0:41:42 | |
of a very purified silicon. | 0:41:42 | 0:41:46 | |
It's very valuable and very precious | 0:41:46 | 0:41:49 | |
and I need to put on some special gloves for this. | 0:41:49 | 0:41:52 | |
It's hard, it's very solid. | 0:41:55 | 0:41:59 | |
It's sort of like a metal and it's incredibly heavy. | 0:41:59 | 0:42:04 | |
Actually, I can hardly lift this thing up, | 0:42:04 | 0:42:08 | |
but it's grown in this very special way here. | 0:42:08 | 0:42:11 | |
This is one crystal of silicon | 0:42:11 | 0:42:13 | |
but it has a seam running all the way along the top here. | 0:42:13 | 0:42:16 | |
This just proves that it is in fact one crystal. | 0:42:16 | 0:42:20 | |
Why do people grow these? | 0:42:20 | 0:42:22 | |
They grow them from the molten silicon. | 0:42:22 | 0:42:26 | |
They would keep purifying it, heating it | 0:42:26 | 0:42:28 | |
and allowing it to cool into this rather strange-looking shape. | 0:42:28 | 0:42:32 | |
They do this because they're trying to make these, | 0:42:32 | 0:42:35 | |
and this is a silicon wafer. | 0:42:35 | 0:42:39 | |
It's just a sheet of silicon, just a slice from this, | 0:42:39 | 0:42:43 | |
and these are used to make silicon chips. | 0:42:43 | 0:42:48 | |
This is the same slice of silicon | 0:42:48 | 0:42:52 | |
and then they're etching in and adding other reagents to this, | 0:42:52 | 0:42:58 | |
gradually building up the silicon chips that we have | 0:42:58 | 0:43:01 | |
in our mobile phones and in our computers. | 0:43:01 | 0:43:06 | |
A fantastic use for this element, silicon. | 0:43:09 | 0:43:12 | |
The element we extract from sand. | 0:43:12 | 0:43:16 | |
Chemists are always finding new uses for the elements. | 0:43:16 | 0:43:19 | |
Even though this has been known for well over 100 years, | 0:43:19 | 0:43:23 | |
it is only relatively recently that we have found out | 0:43:23 | 0:43:27 | |
how to use this element to make silicon chips. | 0:43:27 | 0:43:30 | |
So far in the lecture, | 0:43:30 | 0:43:31 | |
we swapped elements around to make different useful materials. | 0:43:31 | 0:43:34 | |
We've stolen oxygen from iron oxide to make iron, | 0:43:34 | 0:43:37 | |
and we've stolen it from sand. | 0:43:37 | 0:43:39 | |
We've even rearranged the structures of carbon | 0:43:39 | 0:43:42 | |
to turn graphite into diamond. | 0:43:42 | 0:43:45 | |
What we still haven't done is turn one element into another. | 0:43:45 | 0:43:50 | |
That's what the alchemists were trying to do, | 0:43:50 | 0:43:53 | |
to turn lead into gold. Is this possible? | 0:43:53 | 0:43:55 | |
Can we turn one element into another? | 0:43:55 | 0:43:58 | |
Yes, this is the process of radioactivity, | 0:43:58 | 0:44:02 | |
and this occurs deep in the Earth and indeed all around us. | 0:44:02 | 0:44:07 | |
Can we have our periodic table up, please? | 0:44:07 | 0:44:10 | |
Those of you, you elements who are radioactive, | 0:44:10 | 0:44:13 | |
I'd like you to stand up, please. | 0:44:13 | 0:44:15 | |
All the radioactive elements. That's all of this front row here. | 0:44:15 | 0:44:19 | |
Yes, you're all radioactive. | 0:44:19 | 0:44:21 | |
Bismuth, we're not sure about you, you're unknown, | 0:44:21 | 0:44:24 | |
but actually you're so radioactive, | 0:44:24 | 0:44:26 | |
you're no longer who you thought you were. | 0:44:26 | 0:44:28 | |
You'd better sit down again. What does that mean? | 0:44:28 | 0:44:30 | |
Why do you have to sit down again? | 0:44:30 | 0:44:32 | |
It's because during radioactive decay, | 0:44:32 | 0:44:35 | |
an element changes into another element. | 0:44:35 | 0:44:39 | |
If we have cards down for a moment, please? | 0:44:39 | 0:44:42 | |
Remember, what makes an element unique | 0:44:42 | 0:44:45 | |
is the heart of the atom itself. | 0:44:45 | 0:44:48 | |
That's the number of protons that it has within it. | 0:44:48 | 0:44:53 | |
This represents what's inside an atom. | 0:44:53 | 0:44:56 | |
This is its nucleus, and we have to count the number of the red spheres, | 0:44:56 | 0:45:00 | |
these represent the protons, | 0:45:00 | 0:45:02 | |
to work out what element this is. | 0:45:02 | 0:45:04 | |
In fact, this is the element uranium. | 0:45:04 | 0:45:07 | |
The thing about uranium is - oops - it's unstable, | 0:45:07 | 0:45:12 | |
and bits drop off. | 0:45:12 | 0:45:14 | |
The nucleus here just gets so large | 0:45:14 | 0:45:16 | |
that it's very difficult for all these things to stay together | 0:45:16 | 0:45:21 | |
and, yes, bits do drop off and when they drop off, | 0:45:21 | 0:45:24 | |
it's changed into different element. | 0:45:24 | 0:45:26 | |
It's the number of the red protons that define an element, | 0:45:26 | 0:45:31 | |
so if we lose two, | 0:45:31 | 0:45:32 | |
it's no longer what we thought it was to start off with. | 0:45:32 | 0:45:36 | |
Can we find uranium in our periodic table. Where's uranium? | 0:45:36 | 0:45:39 | |
Would you like to stand up? | 0:45:39 | 0:45:44 | |
Uranium, you are radioactive, and bits do drop off. | 0:45:44 | 0:45:48 | |
Quite slowly, don't worry, we won't notice. | 0:45:48 | 0:45:51 | |
But actually when it does happen, when it does fall off, | 0:45:51 | 0:45:54 | |
you change into a different element | 0:45:54 | 0:45:56 | |
and you move a couple of spaces along. | 0:45:56 | 0:45:58 | |
You become thorium, so maybe you should move over to thorium. | 0:45:58 | 0:46:01 | |
Better put your card down because you're not "U" any more. Get it? | 0:46:01 | 0:46:06 | |
You're no longer you, you're actually thorium. | 0:46:06 | 0:46:09 | |
You'd better go over there, you are on thorium's space now. | 0:46:09 | 0:46:13 | |
Actually, both thorium and uranium have also decayed, | 0:46:13 | 0:46:17 | |
and if you decay now, you're going to become the element radon. | 0:46:17 | 0:46:21 | |
You're also radioactive, I'm afraid, so if you decay, | 0:46:21 | 0:46:25 | |
you lose a couple of protons in an alpha particle. | 0:46:25 | 0:46:28 | |
You're not radon any more, you've become polonium. | 0:46:28 | 0:46:32 | |
Can we see this in action? | 0:46:32 | 0:46:34 | |
We can, using this apparatus here. | 0:46:34 | 0:46:38 | |
This is known as a cloud chamber. | 0:46:38 | 0:46:41 | |
The tank that we see here contains an atmosphere of alcohol vapour | 0:46:41 | 0:46:49 | |
and it's got a lot of vapour in there | 0:46:49 | 0:46:51 | |
and it's actually trying to form little droplets. | 0:46:51 | 0:46:55 | |
There's a temperature gradient. | 0:46:55 | 0:46:56 | |
There's a little heating wire at the top and it's cooled down | 0:46:56 | 0:47:00 | |
from underneath, so it's gradually freezing. | 0:47:00 | 0:47:02 | |
It wants to form droplets but actually it's much easier | 0:47:02 | 0:47:06 | |
if there's something there to help it. | 0:47:06 | 0:47:09 | |
Any charged particles can cause this. | 0:47:09 | 0:47:12 | |
All the tracks that you can see now, | 0:47:12 | 0:47:15 | |
all these little wispy white trails, | 0:47:15 | 0:47:18 | |
are actually particles of radiation. | 0:47:18 | 0:47:23 | |
This is natural radiation just in the air around us. | 0:47:23 | 0:47:27 | |
We don't tend to think of radioactivity as being very natural, | 0:47:27 | 0:47:31 | |
but of course, we're all weakly radioactive | 0:47:31 | 0:47:34 | |
because of some of the radioactive elements in us. | 0:47:34 | 0:47:36 | |
Here, we can see radiation in action here just in the air around us. | 0:47:36 | 0:47:42 | |
I'm going to introduce into this a sample of a radioactive element | 0:47:42 | 0:47:48 | |
called americium. | 0:47:48 | 0:47:51 | |
Look at that. You can see the tracks forming here. | 0:47:51 | 0:47:56 | |
Each little track that we see is the result of a charged particle | 0:48:00 | 0:48:06 | |
being emitted from the element americium | 0:48:06 | 0:48:11 | |
and the particles emitted are alpha particles. | 0:48:11 | 0:48:16 | |
The alpha particle is two protons, two neutrons, | 0:48:16 | 0:48:20 | |
and actually that is the heart of an atom of helium. | 0:48:20 | 0:48:25 | |
What we're actually seeing here is the birth of helium atoms, | 0:48:25 | 0:48:31 | |
which I think is quite remarkable. I'll just put this away. | 0:48:31 | 0:48:36 | |
It is possible then to change one atom into another. | 0:48:36 | 0:48:41 | |
Nature seems to do this, but can we? | 0:48:41 | 0:48:45 | |
Actually, it is possible, | 0:48:45 | 0:48:47 | |
and one of the first people to generate lots of different atoms | 0:48:47 | 0:48:50 | |
was this chap here, Glenn Seaborg. | 0:48:50 | 0:48:53 | |
In fact, he even has an element named after him. | 0:48:53 | 0:48:58 | |
Where's seaborgium? There we are, | 0:48:58 | 0:49:00 | |
right in the middle of the periodic table. | 0:49:00 | 0:49:02 | |
In 1980, Seaborg did an amazing experiment. | 0:49:02 | 0:49:07 | |
He took bismuth and he turned it into gold. | 0:49:07 | 0:49:12 | |
This is what the alchemists had been dreaming of. | 0:49:12 | 0:49:15 | |
He changed one element into gold. | 0:49:15 | 0:49:17 | |
What he did was take bismuth - | 0:49:17 | 0:49:19 | |
can we have our periodic table up for a second, please? | 0:49:19 | 0:49:22 | |
He took the element bismuth and he fired atoms of carbon and neon | 0:49:22 | 0:49:27 | |
at this and it knocked out a number of protons | 0:49:27 | 0:49:31 | |
until we ended up with gold. | 0:49:31 | 0:49:34 | |
Unfortunately, he only ended up with the few thousand atoms | 0:49:34 | 0:49:38 | |
and this is not enough to get him rich. | 0:49:38 | 0:49:40 | |
It was a very expensive experiment, took a lot of money to get this | 0:49:40 | 0:49:44 | |
and all he made was a few atoms, but it is possible to do it. | 0:49:44 | 0:49:48 | |
Radioactivity is a natural process but it can also be brought about | 0:49:48 | 0:49:52 | |
by firing one atom at another, | 0:49:52 | 0:49:55 | |
and changing it and creating new, heavier elements | 0:49:55 | 0:49:59 | |
or even to make gold. | 0:49:59 | 0:50:01 | |
Do we even want to make gold? | 0:50:01 | 0:50:02 | |
Are there other things that fascinated the alchemists | 0:50:02 | 0:50:05 | |
which modern scientists have taken one step further? | 0:50:05 | 0:50:08 | |
This is another naturally occurring rock | 0:50:08 | 0:50:11 | |
that has really quite remarkable properties. | 0:50:11 | 0:50:14 | |
This one amazed the early alchemists. | 0:50:14 | 0:50:18 | |
I'll show you why. | 0:50:18 | 0:50:19 | |
Over here, our audience members have some paper clips. | 0:50:19 | 0:50:23 | |
Have you got some paper clips? | 0:50:23 | 0:50:26 | |
I'd like you to put your paper clips onto here, just onto the rock. | 0:50:26 | 0:50:30 | |
They should stick by themselves. | 0:50:32 | 0:50:35 | |
It's not a surprise to us because we've all seen magnets before, | 0:50:35 | 0:50:39 | |
but just imagine if you were the first person to ever see a magnet. | 0:50:39 | 0:50:43 | |
I have a book here from the 1530s | 0:50:43 | 0:50:46 | |
that describes this magnetic rock, this lodestone. | 0:50:46 | 0:50:50 | |
They really did find it quite remarkable. | 0:50:50 | 0:50:53 | |
This here shows this magnetic rock. | 0:50:53 | 0:50:56 | |
There's a ship sailing past a mountain that's supposedly made | 0:50:56 | 0:51:02 | |
of this lodestone, this magnetic ore. | 0:51:02 | 0:51:05 | |
You can see here, these are the nails from the ship. | 0:51:05 | 0:51:09 | |
They've supposedly been sucked out of the ship, so this is | 0:51:09 | 0:51:13 | |
a sort of warning that there's this incredibly strange magical material | 0:51:13 | 0:51:17 | |
with these amazing properties which would suck the nails | 0:51:17 | 0:51:21 | |
out of your ship and you'd be shipwrecked. | 0:51:21 | 0:51:24 | |
There's a warning for you. OK, thank you. | 0:51:24 | 0:51:28 | |
Nowadays, scientists have learned how to make even stronger magnets | 0:51:28 | 0:51:34 | |
from the elements, and if we just have our periodic table up again, | 0:51:34 | 0:51:37 | |
some of the strongest magnets now made use the element neodymium. | 0:51:37 | 0:51:45 | |
Give us a wave, up there, very good. | 0:51:45 | 0:51:48 | |
The strongest magnets in the world are made with neodymium. | 0:51:48 | 0:51:53 | |
This element was discovered in the 1880s, | 0:51:53 | 0:51:55 | |
but it was over 100 years later that scientists learnt how to use | 0:51:55 | 0:52:00 | |
this element to create these magnets. | 0:52:00 | 0:52:03 | |
Thank you very much, periodic table. | 0:52:03 | 0:52:05 | |
I have a couple of these magnets here | 0:52:05 | 0:52:07 | |
and they really are very strong indeed. | 0:52:07 | 0:52:10 | |
These are little neodymium magnets. | 0:52:10 | 0:52:12 | |
Here we are, just try to pull these apart? | 0:52:12 | 0:52:16 | |
I can't. Are they stuck together? | 0:52:16 | 0:52:18 | |
No, they're not stuck together. Try again. | 0:52:18 | 0:52:21 | |
Give them to your neighbour, see if he can get them? | 0:52:21 | 0:52:25 | |
-Can you pull those apart? -No. | 0:52:25 | 0:52:27 | |
I promise you they're not stuck together. | 0:52:27 | 0:52:30 | |
I could probably slide them or something if I push. Look at that. | 0:52:30 | 0:52:35 | |
They're very strong magnets indeed. | 0:52:35 | 0:52:38 | |
Even though the element neodymium has been known for over 100 years, | 0:52:38 | 0:52:42 | |
these magnets have only recently been developed. | 0:52:42 | 0:52:46 | |
Now, these really are quite strong | 0:52:46 | 0:52:48 | |
and I think to show just how strong these are, I need another volunteer. | 0:52:48 | 0:52:54 | |
I think we should have one from this side. | 0:52:54 | 0:52:57 | |
Would you like to come down to the front, please? | 0:52:57 | 0:53:01 | |
APPLAUSE | 0:53:01 | 0:53:05 | |
OK, very good. Are you feeling strong? You are, that's good. | 0:53:05 | 0:53:08 | |
-Tell us your name, please. -Marie. -Marie. | 0:53:08 | 0:53:11 | |
We're just going to bring down this rig here. | 0:53:11 | 0:53:15 | |
We're going to suspend you from the ceiling | 0:53:15 | 0:53:18 | |
using this little magnet here. That's the only magnet. | 0:53:18 | 0:53:22 | |
This is a block of iron. It's not magnetic. | 0:53:22 | 0:53:25 | |
I can show that with a paper clip, | 0:53:25 | 0:53:27 | |
just holding the paper clip, it stays on it | 0:53:27 | 0:53:30 | |
but it's not attracted to it. | 0:53:30 | 0:53:32 | |
This is our magnet. | 0:53:32 | 0:53:33 | |
I'm not going to put the paper clip on this, I'd never get it off again. | 0:53:33 | 0:53:37 | |
If you'd like to come over here, please. | 0:53:37 | 0:53:39 | |
I just need to very carefully put this in the middle. Perfect. | 0:53:39 | 0:53:42 | |
Just clip this on as well. | 0:53:42 | 0:53:46 | |
OK, so you're feeling strong? | 0:53:46 | 0:53:50 | |
If you just hold on to here. That's it. | 0:53:50 | 0:53:54 | |
Can you just raise up the winch then, please? | 0:53:54 | 0:53:57 | |
Hold on strong, hold on tightly and we'll just see if we can lift you | 0:53:57 | 0:54:01 | |
off the ground so you need to hold on very tightly. | 0:54:01 | 0:54:03 | |
Might need to move forward a little bit. | 0:54:03 | 0:54:05 | |
Keep holding on and just watch the feet. | 0:54:05 | 0:54:08 | |
There we are, look at that! | 0:54:08 | 0:54:10 | |
You are now suspended from the ceiling. That's fantastic! | 0:54:10 | 0:54:14 | |
APPLAUSE | 0:54:14 | 0:54:16 | |
It really is pretty strong magnets there. | 0:54:19 | 0:54:21 | |
We can actually hang from them. | 0:54:21 | 0:54:23 | |
It's just using the power of these new magnets | 0:54:23 | 0:54:26 | |
but these are incredibly useful and they find uses for instance | 0:54:26 | 0:54:30 | |
in turbines, but are also used in electric cars and so on as well. | 0:54:30 | 0:54:35 | |
These new materials - very, very useful. | 0:54:35 | 0:54:38 | |
We can create even more amazing materials using the elements. | 0:54:38 | 0:54:42 | |
Can we just have our periodic table up for a moment? | 0:54:42 | 0:54:45 | |
We were using magnets there to suspend | 0:54:45 | 0:54:47 | |
and these were the neodymium magnets, | 0:54:47 | 0:54:50 | |
but this, we're going to use some superconductors | 0:54:50 | 0:54:53 | |
and the superconductors are made from the elements yttrium, | 0:54:53 | 0:54:57 | |
just here. Give us a wave, yttrium. | 0:54:57 | 0:55:00 | |
And from barium, so give us a wave, barium. Very good. | 0:55:00 | 0:55:05 | |
And copper. OK, there's copper, | 0:55:05 | 0:55:08 | |
and oxygen at the top there. | 0:55:08 | 0:55:11 | |
Put you four elements together and we get these amazing materials - | 0:55:11 | 0:55:16 | |
high-temperature superconductors. | 0:55:16 | 0:55:18 | |
This is called a Mobius strip. It's a rather strange looking thing. | 0:55:18 | 0:55:22 | |
-How many sides has this got? -Two. -Well, you'd think so. | 0:55:22 | 0:55:26 | |
Actually, if you start here and you keep on going round, | 0:55:26 | 0:55:30 | |
you actually come back underneath. | 0:55:30 | 0:55:33 | |
If you keep going round, you come back where you started from. | 0:55:33 | 0:55:37 | |
It actually has one side, this mathematical shape, | 0:55:37 | 0:55:40 | |
which is very unusual. | 0:55:40 | 0:55:41 | |
I can show you this using our little superconductor. | 0:55:41 | 0:55:45 | |
This Mobius strip is covered with these neodymium magnets, | 0:55:45 | 0:55:49 | |
these very strong magnets. We've got a superconductor here | 0:55:49 | 0:55:53 | |
and this is the superconductor | 0:55:53 | 0:55:55 | |
that's made from the barium, the yttrium, the copper and the oxygen. | 0:55:55 | 0:56:01 | |
This is the ceramic there. This is this disc in the centre. | 0:56:01 | 0:56:04 | |
We are cooling it with liquid nitrogen | 0:56:04 | 0:56:07 | |
in this little holding tray on the top. | 0:56:07 | 0:56:10 | |
It levitates quite nicely. | 0:56:10 | 0:56:12 | |
There we are, it's come back to where it was. | 0:56:17 | 0:56:22 | |
Now it's actually hanging underneath this strip, | 0:56:22 | 0:56:26 | |
but it needs to be cooled down | 0:56:26 | 0:56:27 | |
so we are cooling it with liquid nitrogen. | 0:56:27 | 0:56:29 | |
That's in order to enable these superconductors to work. | 0:56:29 | 0:56:33 | |
They only work at these very low temperatures, | 0:56:33 | 0:56:36 | |
so eventually it's going to warm up and it will fall off the track | 0:56:36 | 0:56:39 | |
so you need to catch it when it does fall. | 0:56:39 | 0:56:43 | |
You're meant to catch it! | 0:56:43 | 0:56:45 | |
Just pass it to me straight away, thank you. That's lovely. | 0:56:45 | 0:56:48 | |
Thank you very much. Thank you for all your help there. | 0:56:50 | 0:56:53 | |
APPLAUSE | 0:56:53 | 0:56:56 | |
Really quite remarkable properties then of this ceramic | 0:57:03 | 0:57:07 | |
made out of the elements barium, yttrium, copper and oxygen. | 0:57:07 | 0:57:11 | |
We've come a long way since the days of the alchemists | 0:57:11 | 0:57:14 | |
when the whole world could be made from air, water, earth and fire. | 0:57:14 | 0:57:19 | |
I hope you've enjoyed our quest to discover | 0:57:19 | 0:57:21 | |
what's really making up the world around us. | 0:57:21 | 0:57:24 | |
If you remember one thing from these lectures, | 0:57:24 | 0:57:27 | |
it's that the work of the chemist is not complete. | 0:57:27 | 0:57:30 | |
New combinations are being discovered all the time | 0:57:30 | 0:57:33 | |
and nobody knows what exciting properties they may have. | 0:57:33 | 0:57:37 | |
I'd like everyone to pick up your cards one last time | 0:57:37 | 0:57:39 | |
and have a look at your card. | 0:57:39 | 0:57:42 | |
Just remember what element you've got, and I want you to go home | 0:57:42 | 0:57:46 | |
and research about your element | 0:57:46 | 0:57:48 | |
and think what uses can we put this element to, | 0:57:48 | 0:57:51 | |
and what new possibilities could there be? Who knows? | 0:57:51 | 0:57:55 | |
You may be able to solve some of the challenges of the future | 0:57:55 | 0:57:58 | |
and maybe even make something more valuable than gold. | 0:57:58 | 0:58:02 | |
Thank you and goodnight. | 0:58:02 | 0:58:04 | |
APPLAUSE | 0:58:04 | 0:58:06 | |
Subtitles by Red Bee Media Ltd | 0:58:09 | 0:58:12 |