字幕列表 影片播放 列印英文字幕 I just think it's so wonderful. We always think of these scientists in the past as being saints. And here he is sitting in his office thinking "Hee hee I've made my competitor feel uncomfortable" And in a way it's sad that we lose these bits of information because it makes science seem so much more exciting. We're in the library of the Royal Society Looking at letters about Radon. Radon is the heaviest of the noble gases and in the early nineteen hundreds there was still a big argument about the work and trying to isolate Radon. Radon is given off as a gas in the radioactive decay of Radium. Radium decays radioactively emitting an alpha particle - that's a nucleus of Helium with the mass 4 - and generates Radon. Radon is itself radioactive and decays so you have to have it, as it were, freshly made. Rather like you can only get fresh meat. If you keep it for a long time it decays away. The half life of the most stable isotope of Radon is just over three days so it's really relatively short lived. That means if you have a certain amount of gas, after three days you'll only have half of it. Another three days a quarter of it. And by the time you come back from your holidays most of it's gone. In the days that this letter was written, the way they were getting it was from the decay of Radium. In fact I've read - and this is quite exciting. It's the first time you've ever seen a glass in the library because they're strictly forbidden. - The way they did it was to take a glass vessel and fill it with water. Imagine now you have a container of water with a piece of Radium metal at the bottom. It is breaking down, generating Radon gas and bubbles of this gas will go up to the top. very small amounts of gas, bacause Radium doesn't decay very fast. And so, we can imagine that Rutherford and Ramsay are really competing to get the first sample to characterize it. And because it also contains alpha particles, it will be contaminated with Helium. You've got to realize that these famous scientists were extraordinarily competitive. They wanted to get there first. And they considered the other one, really a bit of a scoundrel. And so there was a sort of competition which is difficult for us now to imagine. And in fact Rutherford was really rude about Ramsay's work. He says, his work - that's Ramsay's work - is all right superficially, on the surface, but when you get down in it you begin to see the nothingness of it all. So he thinks it's rubbish. So this is in a private letter to his friend Schuster - Schuster was his surname -and he begins, "My dear Schuster", because in those days you called your friends by their surnames. No first names; It wasn't right. And this was written on July 30th 1908, so more than a hundred years ago. The reason he's written this letter, is because he's real excited he has got a spectrum of this Radon gas. It wasn't called Radon then; It was called Radium Emanation - Emanation means "coming out of Radium." And he's got a spectrum, and Ramsay hasn't. It was really quite exciting. And so he sent a photograph. And, this is the photograph. So, Rutherford has signed this and he said, "Some of the lines run together in the reproduction" - that's the print - " and ??? they're quite clear in the negative" So, he had an experiment in which he had a small amount of this gas, not more than 0.2 of a cubic centimeter, so it's not very much, in which presumably, though he doesn't say so, he put an electric discharge through it so that the gas glowed. Rather like a Neon sign glows red in a shopping center. And he then photographed this light coming out with a photographic film, using a spectroscope to spread out the different colours. All these gases give a whole series of lines and this is a print of his photograph, because you get a negative in the pho... originally and then he's printed it. If you come close you can see it says the "SPECTRUM OF RADIUM EMANATION" There are actually three spectra here. At the top and the bottom are the spectra of Helium gas as a calibration so that he can see what the wavelengths are. And he's written, all the way down here, the wavelengths of the Helium lines. You can see Rutherford has fantastically good small handwriting, or it might have been his assistant, Kay, who wrote this, because his handwriting looks pretty difficult to read. And then, in the middle, is the spectrum of Radon - Radium Emanation It shows that Radon is a completely separate element. And he's really excited because this is the first spectrum that he believes in. Ramsay claims to have got a spectrum, but Rutherford doesn't believe him. I don't know, because it doesn't say here, whether Rutherford ever published this spectrum apart from just sending it to his friend, but it sounds as if he's going to publish it, because he wrote, "I think Royds" - that's his colleague - "and I, have certainly succeeded in making Ramsay temporally very unhappy." We always think of these scientists in the past as being saints. And here he is sitting in his office thinking, "Hee hee I've made my competitor feel uncomfortable." Do you ever feel like that when you get one up on your scientific colleagues/collaborators/rivals? You say it's a wonderful thing and a human thing. Let me put you on the spot. Do you ever take delight in beating people to things? I don't usually get quite so aggressive, perhaps it's not my nature, though I did get quite excited when I made a compound that my German friend, Friedrich, couldn't and I felt really quite good about that, but in a friendly sort of way. I was not hoping that he would be sitting there, um, crying or whatever, but there are stories of Nobel prize winners tearing up journals or jumping up and down on the journals when their rival has published something else. And I think it's important to realize that it's good to feel emotional about these things because then you may have better ideas. If you're sitting there, cold and calculating and not very involved, perhaps you won't have the brilliant breakthrough that you might do otherwise. I don't know what happened. I suspect that Rutherford became more interested in the structure of the atom and, having got this and so on, lost his enthusiasm or got more excited about something else, because in the end, if you look in the books, it's Ramsay who's credited with discovering Radon, though according to some sources, he didn't want to call it Radon and he thought of a nice name, he wanted to call it Niton for some rather obscure Latin derivation. But I think Radon is a nice name. It sounds a bit like Argon or Xenon and also, it connects it very nicely with Radium. So, as names go, it's really quite a good and understandable name. As far as I know nobody has really studied the chemistry of Radon in much detail but, because it's below Xenon in the periodic table there will be quite an extensive chemistry. You will be able to make Fluorine compunds, probably oxides and a variety of other ones. And generally, as you go down the periodic table the chemistry of the noble gases gets richer and richer. A couple of years ago, Brady and I went to an institute in Germany, in Darmstadt, and they had a display for the public of a cloud chamber. Ok we have a cloud chamber here and I will now inject radioactive Radon gas into the chamber and you will see that there is a lot of radioactive decay going on when I inject it. So now we have to wait a second for the gas inside And Brady and I sat there for some time, watching these trails, which look really very beautiful.