WEBVTT 00:00:00.030 --> 00:00:02.400 The following content is provided under a Creative 00:00:02.400 --> 00:00:03.830 Commons license. 00:00:03.830 --> 00:00:06.850 Your support will help MIT OpenCourseWare continue to 00:00:06.850 --> 00:00:10.510 offer high-quality educational resources for free. 00:00:10.510 --> 00:00:13.390 To make a donation or view additional materials from 00:00:13.390 --> 00:00:17.490 hundreds of MIT courses, visit MIT OpenCourseWare at 00:00:17.490 --> 00:00:18.740 ocw.mit.edu. 00:00:21.050 --> 00:00:21.470 PROFESSOR: OK. 00:00:21.470 --> 00:00:22.720 So. 00:00:24.740 --> 00:00:27.590 Last day we started looking at phase diagrams, and we looked 00:00:27.590 --> 00:00:31.780 at unary phase diagrams, one component systems, and one 00:00:31.780 --> 00:00:35.060 component system P versus T, pressure versus temperature. 00:00:35.060 --> 00:00:39.130 And this is the situation for water. 00:00:39.130 --> 00:00:42.370 Water is an exception, because it's got this negative solid 00:00:42.370 --> 00:00:47.330 equals liquid coexistence curve, but otherwise, you have 00:00:47.330 --> 00:00:50.970 large, single-phase regions here, which I've designated 00:00:50.970 --> 00:00:55.100 circle p equals 1, and then along these lines, we have 00:00:55.100 --> 00:00:56.310 equilibria. 00:00:56.310 --> 00:00:59.230 So this is liquid goes to vapor, this is solid goes to 00:00:59.230 --> 00:01:01.410 liquid, this is solid goes to vapor. 00:01:01.410 --> 00:01:05.640 And we know that for water, if we take the 1 atmosphere, if 00:01:05.640 --> 00:01:08.800 this is pressure in atmospheres, the 1 atmosphere 00:01:08.800 --> 00:01:13.490 isobar, then that would put this point at 100 degrees 00:01:13.490 --> 00:01:16.470 Celsius, and this point at 0 Celsius. 00:01:16.470 --> 00:01:21.420 And then we have the triple point, which is solid equals 00:01:21.420 --> 00:01:27.620 liquid equals vapor at 0.01 degrees C, and p equals, I 00:01:27.620 --> 00:01:31.920 think it was 4.58 millimeters of mercury. 00:01:31.920 --> 00:01:35.030 So that's the triple point. 00:01:35.030 --> 00:01:39.720 And we looked at a variety of other one-component phase 00:01:39.720 --> 00:01:44.670 diagrams, and I think we came to a pretty good 00:01:44.670 --> 00:01:46.370 understanding. 00:01:46.370 --> 00:01:48.540 And then up here, we have the supercritical fluids. 00:01:48.540 --> 00:01:50.430 So I've got a break in the line here. 00:01:50.430 --> 00:01:55.640 And for water, you reach supercriticality at 374 00:01:55.640 --> 00:02:03.230 degrees Celsius, and up here at 218 atmospheres. 00:02:03.230 --> 00:02:05.990 So these are not phenomenal, these are not geological 00:02:05.990 --> 00:02:07.630 pressures at all. 00:02:07.630 --> 00:02:11.530 And so that's if we want to the decaffeinating of 00:02:11.530 --> 00:02:12.440 coffee and so on. 00:02:12.440 --> 00:02:14.960 And so what happens here, is you have a highly compressed 00:02:14.960 --> 00:02:18.410 vapor or a highly rarefied liquid, and you end up with 00:02:18.410 --> 00:02:21.690 solubilizing power of a liquid, but transport 00:02:21.690 --> 00:02:22.720 properties of a gas. 00:02:22.720 --> 00:02:25.700 So this stuff has really good diffusivity. 00:02:25.700 --> 00:02:28.880 So it can penetrate into interstices and do its work 00:02:28.880 --> 00:02:31.220 very quickly, to say nothing of the fact that you're up at 00:02:31.220 --> 00:02:34.760 374 degrees Celsius or higher. 00:02:34.760 --> 00:02:37.130 So today what I want to do, is I want to look at 00:02:37.130 --> 00:02:44.280 two-component systems. So component number is circle c, 00:02:44.280 --> 00:02:45.540 c equals 2. 00:02:45.540 --> 00:02:48.610 So that means now I have to deal with pressure, 00:02:48.610 --> 00:02:52.240 temperature, and lowercase c is composition. 00:02:52.240 --> 00:02:55.070 I want to know how things vary with composition. 00:02:55.070 --> 00:02:56.180 So let me give you an example. 00:02:56.180 --> 00:02:59.010 Suppose I have two substances, A and B. 00:02:59.010 --> 00:03:02.820 So here's substance A, and I've got its one-component 00:03:02.820 --> 00:03:03.620 phase diagram. 00:03:03.620 --> 00:03:07.670 And in this case, I'm going to put solid-liquid vapor in the 00:03:07.670 --> 00:03:10.830 conventional setting, where the solid-liquid line is-- 00:03:10.830 --> 00:03:13.140 the coexistence curve has a positive slope. 00:03:13.140 --> 00:03:16.690 So this is A, and let's say I've got B over here, and it's 00:03:16.690 --> 00:03:20.450 got its solid-liquid coexistence curve, and so 00:03:20.450 --> 00:03:24.120 we've got its melting point, and whatever. 00:03:24.120 --> 00:03:26.210 So now the question I want to ask is, what happens 00:03:26.210 --> 00:03:28.390 if I mix A and B? 00:03:28.390 --> 00:03:32.790 And let's just say, here's the melting point of A, so this is 00:03:32.790 --> 00:03:35.380 at p equals 1 atmosphere. 00:03:35.380 --> 00:03:37.130 And here's the melting point of B. 00:03:37.130 --> 00:03:39.450 And I want to ask the question, how does the melting 00:03:39.450 --> 00:03:41.890 point of the mixture vary? 00:03:41.890 --> 00:03:45.020 So let's say I'm going to connect these, and I want to 00:03:45.020 --> 00:03:48.170 ask, what happens if I've got an AB mixture? 00:03:48.170 --> 00:03:50.240 So I'm going to put lowercase c here, which is 00:03:50.240 --> 00:03:51.560 concentration. 00:03:51.560 --> 00:03:54.320 So at the one end, I've got 100% A, and over here, I've 00:03:54.320 --> 00:03:57.130 got 100% B, and I know those melting points. 00:03:57.130 --> 00:03:59.040 Question is, what happens when I mix them? 00:03:59.040 --> 00:04:01.180 Does the melting point-- is it just a straight line? 00:04:01.180 --> 00:04:02.770 Is it a linear variation? 00:04:02.770 --> 00:04:04.160 Do you go through a local maximum? 00:04:04.160 --> 00:04:06.180 Do you go through a local minimum? 00:04:06.180 --> 00:04:07.240 Or do you go wild? 00:04:07.240 --> 00:04:08.560 I mean, what happens? 00:04:08.560 --> 00:04:11.620 So a question you might ask is, suppose I made a 50-50 00:04:11.620 --> 00:04:15.530 alloy of 50% A and 50% B. 00:04:15.530 --> 00:04:18.660 If I knew the end-member melting points, could I 00:04:18.660 --> 00:04:19.850 predict this? 00:04:19.850 --> 00:04:21.870 Or if not, do I have an archive? 00:04:21.870 --> 00:04:24.920 Remember the phase diagram compendium is an archive. 00:04:24.920 --> 00:04:27.170 What is the value of the melting 00:04:27.170 --> 00:04:30.320 point at 50-50 or 75-25? 00:04:30.320 --> 00:04:32.400 So that's the question I want to ask. 00:04:32.400 --> 00:04:35.900 Now this is getting really messy, because now I have to 00:04:35.900 --> 00:04:41.320 plot pressure, and I have to plot temperature, and I have 00:04:41.320 --> 00:04:43.720 to plot composition. 00:04:43.720 --> 00:04:46.000 So this is really crazy, right? 00:04:46.000 --> 00:04:48.870 I've got pressure, and I'm going to have composition 00:04:48.870 --> 00:04:51.020 here, and I'm going to have to have now a third 00:04:51.020 --> 00:04:52.020 axis, aren't I? 00:04:52.020 --> 00:04:53.710 I'm going to have to have a third axis. 00:04:53.710 --> 00:04:55.230 I'm going to need a temperature axis. 00:04:55.230 --> 00:04:57.700 And I've got to make a three-dimensional drawing. 00:04:57.700 --> 00:04:59.370 And this is messy. 00:04:59.370 --> 00:05:07.730 But we're in luck, because 3091 is solid state chemistry. 00:05:07.730 --> 00:05:10.750 So as solid state chemists, we're more interested in what 00:05:10.750 --> 00:05:12.480 happens in the solid here. 00:05:12.480 --> 00:05:15.080 Now, I've drawn these lines with a slope, but they're 00:05:15.080 --> 00:05:16.370 really not to scale. 00:05:16.370 --> 00:05:20.140 It turns out that, you know, you can move 10,000 feet up or 00:05:20.140 --> 00:05:24.280 down in the atmosphere and have a huge variation in the 00:05:24.280 --> 00:05:27.100 boiling point because this line is shallow. 00:05:27.100 --> 00:05:29.360 But this line is virtually straight up and down. 00:05:29.360 --> 00:05:32.170 You have to go to geological pressures to change the 00:05:32.170 --> 00:05:34.160 melting point very much. 00:05:34.160 --> 00:05:38.370 And so, as a result, this is almost insensitive to 00:05:38.370 --> 00:05:40.900 pressure, to first order, right? 00:05:40.900 --> 00:05:48.380 So we can say solid equals liquid is almost insensitive 00:05:48.380 --> 00:05:55.790 to pressure, whereas liquid equals vapor is very sensitive 00:05:55.790 --> 00:05:57.760 very sensitive to pressure. 00:05:57.760 --> 00:06:00.260 But we don't care about this so much. 00:06:00.260 --> 00:06:02.110 So what I'm going to do is throw it away. 00:06:02.110 --> 00:06:06.990 I'm going to throw it away, and just say, let's look at 00:06:06.990 --> 00:06:10.120 just T versus C. 00:06:10.120 --> 00:06:13.490 Temperature versus composition on the strength of the fact 00:06:13.490 --> 00:06:18.800 that the melting point and all of these things are mildly 00:06:18.800 --> 00:06:20.440 dependent on pressure. 00:06:20.440 --> 00:06:21.440 All right. 00:06:21.440 --> 00:06:23.640 So now I'm going to give you three different types. 00:06:23.640 --> 00:06:26.180 There's many, many different types of binary phase diagram. 00:06:26.180 --> 00:06:28.420 So now we're going to be looking at C equals 2. 00:06:28.420 --> 00:06:32.210 So instead of a unary, this is going to be called binary. 00:06:32.210 --> 00:06:36.330 Binary phase diagrams. And they come in all shapes and 00:06:36.330 --> 00:06:38.720 sizes, but they can pretty much be 00:06:38.720 --> 00:06:40.970 classified in several bins. 00:06:40.970 --> 00:06:43.550 And I've made the classification. 00:06:43.550 --> 00:06:51.990 So classify binary phase diagrams 00:06:51.990 --> 00:06:55.252 according to their bonding. 00:06:55.252 --> 00:06:58.360 It all comes back electronic structure and bonding. 00:06:58.360 --> 00:07:02.810 Vary by bonding. 00:07:02.810 --> 00:07:04.860 Because bonding, then, ultimately indicates 00:07:04.860 --> 00:07:06.670 solubility, and that's what we're looking at here. 00:07:06.670 --> 00:07:09.640 We're going to look at how well A dissolves into B, and 00:07:09.640 --> 00:07:11.540 how well B dissolves into A. 00:07:11.540 --> 00:07:12.790 That dictates solubility. 00:07:15.610 --> 00:07:17.630 So it all comes full circle. 00:07:17.630 --> 00:07:21.830 So I've made this up. 00:07:21.830 --> 00:07:23.080 You're now going to find this in the book. 00:07:23.080 --> 00:07:27.800 So I just decided, for ease of teaching 3091, is I'm going to 00:07:27.800 --> 00:07:29.120 just give the different types. 00:07:29.120 --> 00:07:31.330 And so I call them type one, type two, and type three. 00:07:31.330 --> 00:07:32.830 You're not going to find that in the books. 00:07:32.830 --> 00:07:35.010 I made that up, because it's simple. 00:07:35.010 --> 00:07:35.820 So type one. 00:07:35.820 --> 00:07:38.850 What's type one binary phase diagram, according to me? 00:07:38.850 --> 00:07:40.100 What is the type one? 00:07:40.100 --> 00:07:42.040 It means complete solubility. 00:07:46.790 --> 00:07:50.460 So A and B are completely soluble in one another as 00:07:50.460 --> 00:07:51.710 solid and liquids. 00:07:56.240 --> 00:07:57.780 That's the first thing that you'll see on a 00:07:57.780 --> 00:07:59.290 type one phase diagram. 00:07:59.290 --> 00:08:03.360 And the second one is, a change of state is present. 00:08:03.360 --> 00:08:06.160 And you know the only change of state we care about here is 00:08:06.160 --> 00:08:07.550 solid goes to liquid. 00:08:07.550 --> 00:08:10.835 So we're going to show solid goes to liquid, and the thing 00:08:10.835 --> 00:08:15.360 is totally, as they say in California, totally soluble as 00:08:15.360 --> 00:08:16.660 liquids and solids. 00:08:16.660 --> 00:08:20.120 Now, here's some bonding rules that you can think about. 00:08:20.120 --> 00:08:22.850 So what would be the characteristics of two 00:08:22.850 --> 00:08:25.900 substances A and B that would give complete solid 00:08:25.900 --> 00:08:26.880 solubility? 00:08:26.880 --> 00:08:31.010 Well, one thing is they'd have to have identical crystal 00:08:31.010 --> 00:08:32.320 structures. 00:08:32.320 --> 00:08:34.280 That would heighten the chances of this. 00:08:34.280 --> 00:08:37.780 Identical crystal structures. 00:08:37.780 --> 00:08:40.480 So if they're both FCC metals, you've got a better chance of 00:08:40.480 --> 00:08:45.890 making an infinite variation in solution composition than 00:08:45.890 --> 00:08:49.080 if one is an FCC metal and the other is a BCC metal because 00:08:49.080 --> 00:08:52.160 FCC will just sit on the lattice site. 00:08:52.160 --> 00:08:53.850 But there's more fine structures. 00:08:53.850 --> 00:09:00.620 Second one is similar atomic volumes. 00:09:00.620 --> 00:09:03.370 So if we're going to have a substitutional solid solution, 00:09:03.370 --> 00:09:05.950 let's make sure we're replacing oranges with 00:09:05.950 --> 00:09:09.360 oranges, and not trying to put a grapefruit on a site that 00:09:09.360 --> 00:09:11.405 normally is occupied by a lemon, because there's going 00:09:11.405 --> 00:09:13.460 to be a size restriction there. 00:09:13.460 --> 00:09:16.100 And the third thing is, even if they have identical crystal 00:09:16.100 --> 00:09:19.740 structures and similar atomic volumes, you can still run 00:09:19.740 --> 00:09:22.870 into trouble with respect to complete solid solubility if 00:09:22.870 --> 00:09:26.910 you have a large variation in electronegativity. 00:09:26.910 --> 00:09:28.500 And I'll show you an example of that. 00:09:28.500 --> 00:09:30.090 So if you have a small difference in 00:09:30.090 --> 00:09:32.980 electronegativity, it means there's a low propensity for 00:09:32.980 --> 00:09:37.410 polarity, and ultimately no chance of electron transfer. 00:09:37.410 --> 00:09:39.510 So I think it's pretty cool. 00:09:39.510 --> 00:09:41.930 So I wrote those down, but was disappointed to learn that for 00:09:41.930 --> 00:09:45.870 metals, they were enunciated about 75 years ago by the 00:09:45.870 --> 00:09:47.910 British metallurgist Hume-Rothery. 00:09:47.910 --> 00:09:50.560 So I can't take credit for this. 00:09:50.560 --> 00:09:51.420 This is one name. 00:09:51.420 --> 00:09:53.170 It's one of these hyphenated British names. 00:09:53.170 --> 00:09:57.090 He's Sir da-da-da-da Hume-Rothery. 00:09:57.090 --> 00:09:59.590 So he has the Hume-Rothery Rule. 00:09:59.590 --> 00:10:05.590 And he called such systems that mix as binaries forming 00:10:05.590 --> 00:10:11.860 isomorphous, meaning they have the same structure. 00:10:11.860 --> 00:10:16.010 So let's take a look at the prototypical isomorphous phase 00:10:16.010 --> 00:10:18.010 diagram, and it looks like this. 00:10:18.010 --> 00:10:20.860 We're plotting temperature versus composition. 00:10:20.860 --> 00:10:22.750 We threw away the pressure coordinate. 00:10:22.750 --> 00:10:25.770 So I got pure A on the left, pure B on the right. 00:10:25.770 --> 00:10:28.570 Little c is concentration, so it varies from 00:10:28.570 --> 00:10:31.210 100% A to 100% B. 00:10:31.210 --> 00:10:34.370 And the vertical axis is temperature. 00:10:34.370 --> 00:10:37.850 So one extreme, I've got the melting point-- 00:10:37.850 --> 00:10:40.270 this is a melting point of pure A. 00:10:40.270 --> 00:10:41.980 And at the other extreme, I've got the melting 00:10:41.980 --> 00:10:44.020 point of pure B. 00:10:47.040 --> 00:10:47.775 So that, we know. 00:10:47.775 --> 00:10:51.200 And now the question is, how does melting point vary as a 00:10:51.200 --> 00:10:52.520 function of composition? 00:10:52.520 --> 00:10:58.540 And for an isomorphous phase diagram, it looks like this: 00:10:58.540 --> 00:11:01.000 lens-shaped. 00:11:01.000 --> 00:11:05.210 Up here is all liquid. 00:11:05.210 --> 00:11:07.550 You see A and B mix in all proportions. 00:11:07.550 --> 00:11:09.020 And down here is all solid. 00:11:12.730 --> 00:11:17.410 And furthermore, it's an all-liquid solution. 00:11:17.410 --> 00:11:17.890 It's a mixture. 00:11:17.890 --> 00:11:19.660 And this is an all-solid solution. 00:11:22.980 --> 00:11:28.940 And then comes the piece that if you take enough 00:11:28.940 --> 00:11:30.900 thermodynamics, you'll be able to rationalize. 00:11:30.900 --> 00:11:33.520 I'm simply going to tell you without proof that when you 00:11:33.520 --> 00:11:38.800 have a multicomponent system, when c is greater than 1-- so 00:11:38.800 --> 00:11:40.090 we're in that situation. 00:11:40.090 --> 00:11:41.840 Now, c is 2. 00:11:41.840 --> 00:11:52.160 When c is greater than 1, it is impossible to move from one 00:11:52.160 --> 00:11:53.880 field, up here, this is-- 00:11:53.880 --> 00:11:55.840 I'd better put the label on it-- this is a 00:11:55.840 --> 00:11:57.390 single-phase field. 00:11:57.390 --> 00:12:01.970 So up here, p equals 1, because it's homogeneous 00:12:01.970 --> 00:12:04.580 liquid solution, p equals 1. 00:12:04.580 --> 00:12:06.050 When you're in pure materials, you can go 00:12:06.050 --> 00:12:07.140 from solid to liquid. 00:12:07.140 --> 00:12:09.240 But when you're in a two-component system, you 00:12:09.240 --> 00:12:12.770 cannot move from one single-phase field to a second 00:12:12.770 --> 00:12:14.700 single-phase field without moving 00:12:14.700 --> 00:12:16.820 through a two-phase field. 00:12:16.820 --> 00:12:22.300 And we'll get to that, what it means to move from one field 00:12:22.300 --> 00:12:32.860 of p equals 1 to another field of p equals 1 requires 00:12:32.860 --> 00:12:45.270 traverse or transit across a field of p equals 2. 00:12:45.270 --> 00:12:47.360 And so what's in here has to be the end member. 00:12:47.360 --> 00:12:50.970 So this must be liquid plus solid. 00:12:50.970 --> 00:12:54.080 So I'm going to call it slush. 00:12:54.080 --> 00:12:56.660 They have a slush in here. 00:12:56.660 --> 00:13:01.660 The other terminology that people give this is, it's 00:13:01.660 --> 00:13:02.900 lens-shaped, right? 00:13:02.900 --> 00:13:04.100 Looks like a lens. 00:13:04.100 --> 00:13:06.150 So let's call this lens shape. 00:13:06.150 --> 00:13:07.570 So we're going to use the Latin word for 00:13:07.570 --> 00:13:09.760 lens, which is lens. 00:13:09.760 --> 00:13:11.670 But we want to make it adjectival. 00:13:11.670 --> 00:13:13.820 So we're going to use the adjective-- 00:13:13.820 --> 00:13:17.020 what's the genetive form of lens? 00:13:17.020 --> 00:13:17.640 Lentis? 00:13:17.640 --> 00:13:20.360 So we will call this lenticular. 00:13:20.360 --> 00:13:21.740 This is lenticular. 00:13:21.740 --> 00:13:25.280 The phase diagram has a lenticular shape. 00:13:25.280 --> 00:13:28.530 Looks like a lens. 00:13:28.530 --> 00:13:32.760 And you know, just as over here, I showed you, every line 00:13:32.760 --> 00:13:35.510 represents a coexistence curve, right? 00:13:35.510 --> 00:13:37.680 The lines are all coexistence curves. 00:13:37.680 --> 00:13:39.830 These lines are coexistence curves. 00:13:39.830 --> 00:13:43.740 The line up here is liquid equals vapor, so this one must 00:13:43.740 --> 00:13:46.570 be the coexistence of the two things on either side. 00:13:46.570 --> 00:13:47.530 So what do I have here? 00:13:47.530 --> 00:13:48.330 I have liquid. 00:13:48.330 --> 00:13:49.650 Here I have slush. 00:13:49.650 --> 00:13:50.750 So I'm going to write that. 00:13:50.750 --> 00:13:54.240 So I'm going to write the equilibrium, liquid goes to 00:13:54.240 --> 00:13:55.890 liquid plus solid. 00:13:55.890 --> 00:13:58.810 And this line, this coexistence curve, it's called 00:13:58.810 --> 00:14:01.650 the liquidus line. 00:14:06.950 --> 00:14:11.730 This is the liquidus equilibrium, the liquidus 00:14:11.730 --> 00:14:13.690 coexistence curve, and so on. 00:14:13.690 --> 00:14:14.800 And so what's the liquidus? 00:14:14.800 --> 00:14:16.800 The liquidus is the lowest temperature. 00:14:16.800 --> 00:14:18.370 So you pick a composition. 00:14:18.370 --> 00:14:21.200 The liquidus is the lowest temperature at which you can 00:14:21.200 --> 00:14:24.490 have a single-phase liquid solution, OK? 00:14:24.490 --> 00:14:26.730 So liquidus equilibrium. 00:14:26.730 --> 00:14:39.610 And the liquidus is the lowest temperature at which all 00:14:39.610 --> 00:14:43.185 liquid is stable. 00:14:43.185 --> 00:14:45.830 You go below that temperature at that composition, you start 00:14:45.830 --> 00:14:48.630 making solid, because slush requires that there be some 00:14:48.630 --> 00:14:50.190 solid present. 00:14:50.190 --> 00:14:53.960 And then the lower line, it also is a coexistence curve. 00:14:53.960 --> 00:14:55.400 So on the one side, I've got solid. 00:14:55.400 --> 00:14:57.300 On the other side, I've got slush. 00:14:57.300 --> 00:14:58.570 So I'm going to write that one down. 00:14:58.570 --> 00:15:02.790 That solid goes to liquid plus solid. 00:15:02.790 --> 00:15:07.850 And that's called the solidus equilibrium, or that's the 00:15:07.850 --> 00:15:10.830 solidus line, the solidus coexistence curve, and the 00:15:10.830 --> 00:15:11.790 solidus is the complement. 00:15:11.790 --> 00:15:14.920 The solidus is the highest temperature at which you can 00:15:14.920 --> 00:15:15.945 have all solid present. 00:15:15.945 --> 00:15:19.340 So you pick a composition, and I'll tell you what the highest 00:15:19.340 --> 00:15:21.270 temperature is at which you'll have a 00:15:21.270 --> 00:15:23.100 single-phase solid solution. 00:15:23.100 --> 00:15:33.820 So solidus is the highest temperature at which 00:15:33.820 --> 00:15:39.310 all solid is stable. 00:15:39.310 --> 00:15:40.930 All right. 00:15:40.930 --> 00:15:41.210 Good. 00:15:41.210 --> 00:15:43.320 And I'm going to look at a few of these things. 00:15:43.320 --> 00:15:46.550 It's always fun to see if I'm on track with the 00:15:46.550 --> 00:15:47.330 Hume-Rothery rule. 00:15:47.330 --> 00:15:50.650 So here's copper nickel. 00:15:50.650 --> 00:15:52.420 They're both FCC metals. 00:15:52.420 --> 00:15:55.990 So we've got copper melting at about 1085, nickel melting at 00:15:55.990 --> 00:15:57.220 about 1455. 00:15:57.220 --> 00:16:01.020 And there's the phase diagram, lenticular phase diagram. 00:16:01.020 --> 00:16:03.530 So up here is all liquid, and then-- 00:16:03.530 --> 00:16:05.490 this is all metallurgy terminology. 00:16:05.490 --> 00:16:11.740 A solid solution of A and B, they call alpha. 00:16:11.740 --> 00:16:13.690 Metallurgist looks at that, goes oh, it must be a solid 00:16:13.690 --> 00:16:15.130 solution, OK? 00:16:15.130 --> 00:16:17.230 So there's p equals 2 in between, 00:16:17.230 --> 00:16:19.740 p equals 1, p equals-- 00:16:19.740 --> 00:16:21.330 Here's a ceramic system. 00:16:21.330 --> 00:16:24.030 This is nickel oxide, magnesium oxide. 00:16:24.030 --> 00:16:26.890 It's not metals, but they have identical crystal structures, 00:16:26.890 --> 00:16:28.800 very similar atomic volumes. 00:16:28.800 --> 00:16:31.990 They're ions, so we have nickel and magnesium 00:16:31.990 --> 00:16:35.440 substituting for one another on the cationic sublattice. 00:16:35.440 --> 00:16:38.750 So they must have very nearly equal sizes. 00:16:38.750 --> 00:16:42.010 If I look at this, and I see a lenticular diagram, it means 00:16:42.010 --> 00:16:44.080 they must have similar atomic volumes, which means the 00:16:44.080 --> 00:16:47.230 dominant defect in here must be Schottky, not Frankel 00:16:47.230 --> 00:16:50.380 because Frankel needs a big difference in atomic volume. 00:16:50.380 --> 00:16:52.520 If you have a big difference in atomic volume, we wouldn't 00:16:52.520 --> 00:16:54.410 have a lenticular phase diagram. 00:16:54.410 --> 00:16:57.530 So here's-- mag oxide melts at 2800 degrees centigrade. 00:16:57.530 --> 00:16:58.430 It's a great refractory. 00:16:58.430 --> 00:17:00.220 You can hold molten iron in it. 00:17:00.220 --> 00:17:02.670 And here's nickel oxide down here. 00:17:02.670 --> 00:17:02.870 All right. 00:17:02.870 --> 00:17:03.770 Here's an interesting one. 00:17:03.770 --> 00:17:04.670 This is gold nickel. 00:17:04.670 --> 00:17:06.220 Both FCC metals. 00:17:06.220 --> 00:17:09.020 Shade your eyes from the lower part. 00:17:09.020 --> 00:17:10.420 Just look at the upper part. 00:17:10.420 --> 00:17:11.670 It looks lenticular. 00:17:13.750 --> 00:17:15.310 It's what you'd expect, gold and nickel. 00:17:15.310 --> 00:17:17.980 They're both, you know, card-bearing metals. 00:17:17.980 --> 00:17:21.940 But you've seen already, with the cesium-gold, gold has a 00:17:21.940 --> 00:17:25.040 fairly high electronegativity. 00:17:25.040 --> 00:17:28.640 And what happens is that you get over here, at about 33 00:17:28.640 --> 00:17:35.320 atomic percent of nickel in gold, you have an atomic ratio 00:17:35.320 --> 00:17:38.310 that allows to have something that starting to approximate 00:17:38.310 --> 00:17:39.250 electron transfer. 00:17:39.250 --> 00:17:41.640 So it's almost as though you have a lenticular phase 00:17:41.640 --> 00:17:46.880 diagram between pure nickel and this nickel-gold compound. 00:17:46.880 --> 00:17:49.750 But up in here, it's nice lenticular stuff. 00:17:49.750 --> 00:17:50.400 All right. 00:17:50.400 --> 00:17:51.970 What's the next one? 00:17:51.970 --> 00:17:52.300 Oh, yeah. 00:17:52.300 --> 00:17:54.690 So now I want to go in and I want to start talking about 00:17:54.690 --> 00:17:56.270 what goes on inside here. 00:17:56.270 --> 00:17:59.780 So what I'm going to do, is I'm going to blow this up. 00:17:59.780 --> 00:18:04.000 And I'm going to start at 40%, 40 weight percent nickel, and 00:18:04.000 --> 00:18:07.100 I'm going to say, what happens if we take a crucible that's 00:18:07.100 --> 00:18:11.330 40 weight percent nickel and copper, and we cool it from 00:18:11.330 --> 00:18:16.810 all liquid at 1300, down to all solid at 1200, pausing in 00:18:16.810 --> 00:18:18.800 that slush zone at 1250? 00:18:18.800 --> 00:18:21.000 So we're going to take snapshots and say, what's the 00:18:21.000 --> 00:18:24.870 contents of the crucible look like at 1300, at 1250, and at 00:18:24.870 --> 00:18:29.030 1200, and come out of it, have an appreciation for what all 00:18:29.030 --> 00:18:30.570 of this stuff means. 00:18:30.570 --> 00:18:33.590 So let's start our experiment. 00:18:33.590 --> 00:18:36.400 So we're going to have three crucibles here. 00:18:36.400 --> 00:18:48.560 And we're going to start with 40% nickel in copper, and 00:18:48.560 --> 00:18:52.880 that's going to be the experiment we'll perform. 00:18:52.880 --> 00:18:55.990 So I've got three crucibles. 00:18:55.990 --> 00:19:00.830 And so if I look at the phase diagram, here I am. 00:19:00.830 --> 00:19:07.690 This was 1300 degrees C, this was at 1250 degrees C, and 00:19:07.690 --> 00:19:10.990 then this was at 1200 degrees C. 00:19:10.990 --> 00:19:13.450 So at 1300, that's trivial. 00:19:13.450 --> 00:19:17.170 1300 for this thing, it should be just all liquid. 00:19:17.170 --> 00:19:18.780 And maybe it's copper. 00:19:18.780 --> 00:19:21.590 I know at this temperature, it's going to be blinding 00:19:21.590 --> 00:19:22.560 white heat. 00:19:22.560 --> 00:19:23.310 So it doesn't matter. 00:19:23.310 --> 00:19:24.000 I could use this. 00:19:24.000 --> 00:19:26.252 But I felt compelled, it's one of those rare opportunities to 00:19:26.252 --> 00:19:27.140 use colored chalk. 00:19:27.140 --> 00:19:29.730 So I want this to sort of be copper-colored. 00:19:29.730 --> 00:19:31.940 The meniscus is going to look like this, because the liquid 00:19:31.940 --> 00:19:33.680 metals have a very high surface tension. 00:19:33.680 --> 00:19:34.910 They want to ball up. 00:19:34.910 --> 00:19:36.850 So you're going to have a meniscus looking like this, 00:19:36.850 --> 00:19:43.100 and this is all single phase, all liquid. 00:19:43.100 --> 00:19:45.640 And over here, I'm going to do the easy one. 00:19:45.640 --> 00:19:48.440 If we get down to 1200, it's all solid state, right? 00:19:48.440 --> 00:19:51.220 At 1200, I'm going to end up with something that's solid, 00:19:51.220 --> 00:19:57.040 and it's going to be polycrystalline, and these are 00:19:57.040 --> 00:19:59.180 all going to be grains of alpha. 00:19:59.180 --> 00:20:02.220 All solid. 00:20:02.220 --> 00:20:05.500 And I'm going to label all of these as alpha solid solution. 00:20:05.500 --> 00:20:09.600 They all have the same composition, which is 40% 00:20:09.600 --> 00:20:11.830 nickel in copper. 00:20:15.490 --> 00:20:18.850 And these are all 40% nickel. 00:20:18.850 --> 00:20:21.930 Now, according to this phase diagram, when we get down into 00:20:21.930 --> 00:20:24.530 the center there, something else happens. 00:20:24.530 --> 00:20:27.150 We end up in a two-phase regime. 00:20:27.150 --> 00:20:30.740 And that two-phase regime is a regime in which certain 00:20:30.740 --> 00:20:34.490 compositions are forbidden because that's an equilibrium. 00:20:34.490 --> 00:20:37.440 It doesn't allow us to have what's in between. 00:20:37.440 --> 00:20:41.840 I think the next slide actually shows this. 00:20:41.840 --> 00:20:49.800 So what I've designated as c2 is this 40%. 00:20:49.800 --> 00:20:54.260 So c2 is now going to park at that point in the middle. 00:20:54.260 --> 00:20:54.850 Whoops! 00:20:54.850 --> 00:20:56.730 Want to get into that. 00:20:56.730 --> 00:20:58.080 So here's where we are. 00:20:58.080 --> 00:21:00.950 We're in the center of that two-phase regime. 00:21:00.950 --> 00:21:02.200 So this is the solidus. 00:21:04.520 --> 00:21:05.770 This is the liquidus. 00:21:08.850 --> 00:21:10.940 And we're at 1250. 00:21:10.940 --> 00:21:12.190 t equals-- 00:21:15.040 --> 00:21:16.740 And we're at this value. 00:21:16.740 --> 00:21:19.580 We started at c2, which is 40%. 00:21:19.580 --> 00:21:24.370 But in this regime, 40% is forbidden. 00:21:24.370 --> 00:21:28.660 If you stop at 40% at 1250, this says that the stable 00:21:28.660 --> 00:21:31.820 phases are a liquid and a solid. 00:21:31.820 --> 00:21:35.460 But the liquid has less nickel in it, and the solid has more 00:21:35.460 --> 00:21:36.530 nickel in it. 00:21:36.530 --> 00:21:38.230 It's like if this is a solubility limit. 00:21:38.230 --> 00:21:41.290 In other words, if you started at pure copper, and you 00:21:41.290 --> 00:21:43.560 started adding nickel, you can keep adding nickel until you 00:21:43.560 --> 00:21:45.150 get to this concentration. 00:21:45.150 --> 00:21:47.000 You try to add any more nickel, it's like adding too 00:21:47.000 --> 00:21:48.130 much sugar to water. 00:21:48.130 --> 00:21:49.310 What do you have? 00:21:49.310 --> 00:21:51.100 The stuff just falls to the bottom of the 00:21:51.100 --> 00:21:52.730 cup, doesn't dissolve. 00:21:52.730 --> 00:21:53.690 That's this. 00:21:53.690 --> 00:21:54.530 It's the solid. 00:21:54.530 --> 00:21:57.710 Only instead of being pure nickel, it's still a copper 00:21:57.710 --> 00:21:59.600 nickel solution, but kind of rich. 00:21:59.600 --> 00:22:01.710 So I'm going to call this c star. 00:22:01.710 --> 00:22:05.240 It's the solubility limit on the liquid side. 00:22:05.240 --> 00:22:08.650 And this one here I'm going to call c star on the solid side. 00:22:08.650 --> 00:22:11.130 In other words, I could start from this side, and keep 00:22:11.130 --> 00:22:14.520 adding copper to nickel, and I make a homogeneous alloy until 00:22:14.520 --> 00:22:15.910 I get to this composition. 00:22:15.910 --> 00:22:19.080 If I try to add any more copper, I jump across. 00:22:19.080 --> 00:22:20.900 So we're here in the middle. 00:22:20.900 --> 00:22:23.050 But now, isn't there something strange here? 00:22:23.050 --> 00:22:27.450 It's saying I'm going to have a liquid that's nickel-poor 00:22:27.450 --> 00:22:29.100 and a solid that's nickel-rich. 00:22:29.100 --> 00:22:32.230 And I'm just putting up here what the diagram says. 00:22:32.230 --> 00:22:35.310 And we know that FCC metals, which is denser, the 00:22:35.310 --> 00:22:37.610 liquid or the solid? 00:22:37.610 --> 00:22:38.200 The solid. 00:22:38.200 --> 00:22:43.430 So down here I'm going to have alpha, OK, a bunch of grains 00:22:43.430 --> 00:22:47.850 of alpha solid solution, and up here, I'm going to have a 00:22:47.850 --> 00:22:49.700 liquid solution. 00:22:49.700 --> 00:22:53.310 And the composition here is c star liquid, and the 00:22:53.310 --> 00:22:56.150 composition here is c star solid. 00:22:56.150 --> 00:22:57.900 It's different composition from this. 00:22:57.900 --> 00:23:02.270 Here the composition is equal to c2, or the 40% nickel. 00:23:02.270 --> 00:23:04.640 So I've got disproportionation. 00:23:04.640 --> 00:23:08.610 But the total mass, I can't have sources or sinks. 00:23:08.610 --> 00:23:10.010 So I have to conserve mass. 00:23:10.010 --> 00:23:12.820 So I'm going to ask you to just do the algebra. 00:23:12.820 --> 00:23:14.760 You've got two equations and two unknowns. 00:23:14.760 --> 00:23:17.730 I know what the n-member concentrations are. 00:23:17.730 --> 00:23:19.930 They're given by the n's of this thing 00:23:19.930 --> 00:23:21.780 called the tie line. 00:23:21.780 --> 00:23:25.170 The tie line ties the two ends of the two-phase region 00:23:25.170 --> 00:23:27.830 together, and then we just do a mass balance. 00:23:27.830 --> 00:23:29.590 Well, fortunately, the metallurgists have thought 00:23:29.590 --> 00:23:31.890 about this for a while, so we don't have to go through and 00:23:31.890 --> 00:23:35.210 figure out, well, if two apples cost 15 cents-- 00:23:35.210 --> 00:23:36.780 we don't have to do that kind of thing. 00:23:36.780 --> 00:23:42.580 We can just invoke the lever rule, and it will tell us how 00:23:42.580 --> 00:23:46.610 much of the liquid that's nickel-depleted and solid 00:23:46.610 --> 00:23:49.060 that's nickel-rich add up to this. 00:23:49.060 --> 00:23:52.320 And so let's look at the lever rule. 00:23:52.320 --> 00:23:55.320 Basically what's going to happen here is that the stuff 00:23:55.320 --> 00:24:04.870 that started off as 40% nickel, 60% copper, that's my 00:24:04.870 --> 00:24:10.700 initial mix, it's going to break into two layers. 00:24:10.700 --> 00:24:13.560 It's going to break into a liquid layer, which, if you go 00:24:13.560 --> 00:24:17.230 to the phase diagram, looks like it's about 38% nickel and 00:24:17.230 --> 00:24:20.255 68% copper, and that's what we're going 00:24:20.255 --> 00:24:22.890 to call c star liquid. 00:24:22.890 --> 00:24:32.030 And then over here it's 45% percent nickel and 55% copper. 00:24:32.030 --> 00:24:36.200 And that's what we call c star of the solid. 00:24:36.200 --> 00:24:37.890 And so it's just a lever. 00:24:37.890 --> 00:24:39.100 So there's c star. 00:24:39.100 --> 00:24:41.500 This is the c2 that we want. 00:24:41.500 --> 00:24:44.600 And we want to ask, what's the relative amount of the liquid 00:24:44.600 --> 00:24:46.630 phase and the solid phase? 00:24:46.630 --> 00:24:49.460 And why they call it a lever rule is, look, if you cooled 00:24:49.460 --> 00:24:51.170 something that was at this composition, it 00:24:51.170 --> 00:24:53.190 would be 100% liquid. 00:24:53.190 --> 00:24:55.530 And if you cooled something at this composition, it will be 00:24:55.530 --> 00:24:56.700 100% solid. 00:24:56.700 --> 00:24:58.530 And so it's going to be a constant 00:24:58.530 --> 00:25:00.420 variation across here. 00:25:00.420 --> 00:25:02.920 So you use, you take this, and you know, and I want this 00:25:02.920 --> 00:25:06.260 amount, I'm taking this versus this, kind of thing. 00:25:06.260 --> 00:25:08.460 It's a lever construction. 00:25:08.460 --> 00:25:09.510 So we'll just put it down. 00:25:09.510 --> 00:25:21.400 So the percent of the liquid in the crucible at 1250-- 00:25:21.400 --> 00:25:22.920 and then this is a general thing. 00:25:22.920 --> 00:25:26.180 Whenever p equals 2, you'll use a lever rule. 00:25:26.180 --> 00:25:30.590 Percent of the liquid is given by this one. 00:25:30.590 --> 00:25:33.760 The composition of the solid at the end of the tie line 00:25:33.760 --> 00:25:36.030 minus the composition that you started at. 00:25:36.030 --> 00:25:41.240 This is your bulk initial concentration, divided by the 00:25:41.240 --> 00:25:43.460 length of that tie line. 00:25:43.460 --> 00:25:48.200 c star solid minus c star liquid. 00:25:48.200 --> 00:25:50.990 And then multiplied by 100%. 00:25:50.990 --> 00:25:54.850 So you get a percent, and the number here is going to be 45 00:25:54.850 --> 00:26:01.850 minus 40 over 45 minus 32, and that works out-- 00:26:01.850 --> 00:26:06.530 going to multiply by 100, or else there will be complaints. 00:26:06.530 --> 00:26:09.290 And then this turns out to be 38%. 00:26:09.290 --> 00:26:11.890 So what that means is that if you take this 00:26:11.890 --> 00:26:15.320 amount of liquid here-- 00:26:15.320 --> 00:26:18.320 pardon me-- based on conservation of mass, if you 00:26:18.320 --> 00:26:28.790 drop and hold at 1250, 38% of that volume is now sitting 00:26:28.790 --> 00:26:35.470 here in the liquid, which means 62% of it by volume has 00:26:35.470 --> 00:26:36.940 turned into solid. 00:26:36.940 --> 00:26:39.620 And the composition here is different from the composition 00:26:39.620 --> 00:26:44.380 here, but if you add up all the nickel in the crucible and 00:26:44.380 --> 00:26:48.180 sum it versus all the copper in the crucible, you still end 00:26:48.180 --> 00:26:49.855 up with 40% net nickel. 00:26:49.855 --> 00:26:52.740 So this very powerful. 00:26:52.740 --> 00:26:55.600 Because what you can do here is you can separate metal. 00:26:55.600 --> 00:27:00.150 Because I started here with 40% nickel, 60% copper, and 00:27:00.150 --> 00:27:02.360 now I've got something-- 00:27:02.360 --> 00:27:06.880 the liquid face, I wrote here, the liquid 00:27:06.880 --> 00:27:10.090 phase is now 68% copper. 00:27:10.090 --> 00:27:12.940 So can you see that if I'm clever about this, I could use 00:27:12.940 --> 00:27:16.730 this as a technique for enriching. 00:27:16.730 --> 00:27:19.790 And if I'm thinking about recycling metals, maybe I need 00:27:19.790 --> 00:27:22.760 to know something about phase diagrams because it's a very 00:27:22.760 --> 00:27:26.320 simple way of concentrating impurities or concentrating 00:27:26.320 --> 00:27:28.390 the desirable stuff. 00:27:28.390 --> 00:27:31.410 Let's look at one other thing here that's really very 00:27:31.410 --> 00:27:32.550 interesting. 00:27:32.550 --> 00:27:37.250 Suppose I had something, instead of c2 at 40%, suppose 00:27:37.250 --> 00:27:38.800 I choose a c1. 00:27:38.800 --> 00:27:41.360 So this is 40% nickel. 00:27:41.360 --> 00:27:46.220 Now what if I take something that's 35% nickel, and I cool 00:27:46.220 --> 00:27:48.390 it down to 1250? 00:27:48.390 --> 00:27:49.570 What happens? 00:27:49.570 --> 00:27:52.460 If I park here at 1250 degrees, according to the 00:27:52.460 --> 00:27:57.280 phase diagram, that substance has to phase separate, and I'm 00:27:57.280 --> 00:27:59.000 going to end up with the same thing. 00:27:59.000 --> 00:28:01.310 I'm going to end up with liquid and solid. 00:28:01.310 --> 00:28:03.380 Now, isn't there a contradiction there? 00:28:03.380 --> 00:28:07.420 How is it that whether I started with 40% or 35%, I end 00:28:07.420 --> 00:28:09.450 up with the same end members? 00:28:09.450 --> 00:28:11.630 What's the missing piece? 00:28:11.630 --> 00:28:14.250 The relative amounts will be different! 00:28:14.250 --> 00:28:15.360 The relative amounts. 00:28:15.360 --> 00:28:16.470 Here, look. 00:28:16.470 --> 00:28:18.960 As I'm getting closer to the liquid, can you see that 00:28:18.960 --> 00:28:21.540 axiomatically, I'm going to make more liquid and less 00:28:21.540 --> 00:28:24.320 solid if I ended up with something over here? 00:28:24.320 --> 00:28:26.610 But at 1250, those are the end members. 00:28:26.610 --> 00:28:29.060 That's the only stuff that's going to be present. 00:28:29.060 --> 00:28:29.970 Ah! 00:28:29.970 --> 00:28:30.610 That's so good. 00:28:30.610 --> 00:28:33.020 I think I've got some other stuff here. 00:28:33.020 --> 00:28:33.320 Oh yeah. 00:28:33.320 --> 00:28:34.140 Oh, this was-- yeah. 00:28:34.140 --> 00:28:36.010 So p equals 2. 00:28:36.010 --> 00:28:37.110 Lever rule. 00:28:37.110 --> 00:28:42.340 Whenever you see p equals 2, you have two things you think 00:28:42.340 --> 00:28:44.390 of. p equals 2 means phase separation. 00:28:47.980 --> 00:28:50.530 And that phase separation means you're going to get 00:28:50.530 --> 00:28:52.410 different amounts, and the lever rule. 00:28:52.410 --> 00:28:54.950 And why I have this Manchurian Candidate-- 00:28:54.950 --> 00:28:55.760 it's this movie. 00:28:55.760 --> 00:28:56.610 I know there's a remake. 00:28:56.610 --> 00:28:58.450 The remake is horrible. 00:28:58.450 --> 00:29:01.360 The original, if you see the original, is about some 00:29:01.360 --> 00:29:02.185 fellows that were brainwashed. 00:29:02.185 --> 00:29:04.890 They were American prisoners of war brainwashed in North 00:29:04.890 --> 00:29:08.210 Korea and they're brainwashed to become assassins on cue. 00:29:08.210 --> 00:29:10.760 And the cue is the Queen of Diamonds. 00:29:10.760 --> 00:29:13.110 When someone shows the Queen of Diamonds, they just go into 00:29:13.110 --> 00:29:15.780 automatic pilot, and they're supposed to assassinate the 00:29:15.780 --> 00:29:16.910 political figure. 00:29:16.910 --> 00:29:21.020 So for you, your Queen of Diamonds is p equals 2. 00:29:21.020 --> 00:29:24.230 When you see p equals 2, you go, phase separation. 00:29:24.230 --> 00:29:25.285 Lever rule. 00:29:25.285 --> 00:29:26.060 All right? 00:29:26.060 --> 00:29:27.500 No guns, just this. 00:29:27.500 --> 00:29:29.160 I just want the formula. 00:29:29.160 --> 00:29:32.360 You go, phase separation, lever rule. 00:29:32.360 --> 00:29:36.370 Whenever p equals two. 00:29:36.370 --> 00:29:38.740 So what happens in here? 00:29:38.740 --> 00:29:39.800 Phase separation. 00:29:39.800 --> 00:29:40.390 Boom, boom. 00:29:40.390 --> 00:29:40.930 Right there. 00:29:40.930 --> 00:29:42.350 Oh, I'm not supposed to say boom, boom. 00:29:42.350 --> 00:29:43.810 Phase separation. 00:29:43.810 --> 00:29:44.430 Ta-da! 00:29:44.430 --> 00:29:45.420 You know, something. 00:29:45.420 --> 00:29:47.080 PC, whatever. 00:29:47.080 --> 00:29:47.390 OK. 00:29:47.390 --> 00:29:48.960 So let's keep going. 00:29:48.960 --> 00:29:52.320 Now I want to look at a second type of phase diagram. 00:29:52.320 --> 00:29:54.630 So the first type of phase diagram was complete 00:29:54.630 --> 00:29:55.870 solubility. 00:29:55.870 --> 00:29:58.730 Now the second type of phase diagram has partial 00:29:58.730 --> 00:29:59.390 solubility. 00:29:59.390 --> 00:30:01.870 So let's look at that one. 00:30:01.870 --> 00:30:03.280 So i call this type two. 00:30:05.830 --> 00:30:06.970 And you don't predict this stuff. 00:30:06.970 --> 00:30:10.270 We would give you the phase diagram and simply ask you, 00:30:10.270 --> 00:30:13.860 you know, you're the specialist. Tell me happens if 00:30:13.860 --> 00:30:16.250 I cool this to such and such a temperature? 00:30:16.250 --> 00:30:18.390 You can tell me you get phase separation, and the 00:30:18.390 --> 00:30:20.470 composition of the two end members, and so on. 00:30:20.470 --> 00:30:23.110 So the characteristics, the bonding characteristics here, 00:30:23.110 --> 00:30:35.880 are partial or limited solubility of A and B. 00:30:35.880 --> 00:30:39.700 We're doing all of this for a binary system A and B, and no 00:30:39.700 --> 00:30:40.950 change of state. 00:30:44.830 --> 00:30:52.920 So that means either always solid, or always liquid. 00:30:52.920 --> 00:30:55.800 That's not to say that the A and B never become solid. 00:30:55.800 --> 00:30:58.960 I'm just saying that a type two diagram is limited to a 00:30:58.960 --> 00:31:03.160 single state. 00:31:03.160 --> 00:31:05.590 So let's take a look at the diagram. 00:31:05.590 --> 00:31:07.380 The diagram looks like this. 00:31:07.380 --> 00:31:10.100 We're going to plot temperature versus 00:31:10.100 --> 00:31:10.860 composition. 00:31:10.860 --> 00:31:14.150 So pure B on the right, pure A on the left. 00:31:14.150 --> 00:31:18.810 Concentration is the abscissa, and then the ordinate, of 00:31:18.810 --> 00:31:20.890 course, is temperature. 00:31:20.890 --> 00:31:24.690 And so the shape of the diagram is this. 00:31:24.690 --> 00:31:27.360 There's the coexistence curve. 00:31:27.360 --> 00:31:32.895 It's called a synclinal coexistence curve. 00:31:38.510 --> 00:31:44.740 So above, we have all solid. 00:31:44.740 --> 00:31:47.430 And in here, we have two solids. 00:31:47.430 --> 00:31:49.990 So using the metallurgical terms, this 00:31:49.990 --> 00:31:51.600 is alpha plus beta. 00:31:51.600 --> 00:31:53.570 Two phase regime, OK? 00:31:53.570 --> 00:31:56.910 So let's get those labels up right off the bat, so we know 00:31:56.910 --> 00:31:57.560 who's where. 00:31:57.560 --> 00:32:02.620 So outside the coexistence curve, p equals 1. 00:32:02.620 --> 00:32:05.830 Inside the coexistence curve, p equals 2. 00:32:05.830 --> 00:32:08.440 And wherever I'm saying all solid, alpha plus beta, I 00:32:08.440 --> 00:32:11.700 could write all liquid, and then it goes to l1 plus l2. 00:32:11.700 --> 00:32:15.780 So maybe we should do that, to show that we're multilingual. 00:32:15.780 --> 00:32:22.680 So it's either all solid, or it could be all liquid. 00:32:22.680 --> 00:32:25.080 And then this would be liquid 1 plus liquid 2. 00:32:28.070 --> 00:32:31.400 And so why do we call it synclinal? 00:32:31.400 --> 00:32:32.570 What's this? 00:32:32.570 --> 00:32:34.320 This is an incline. 00:32:34.320 --> 00:32:35.970 If I put two inclines and I synchronize 00:32:35.970 --> 00:32:37.780 them, I get a syncline. 00:32:37.780 --> 00:32:39.300 And if I don't synchronize them-- 00:32:39.300 --> 00:32:40.060 these are two ladders. 00:32:40.060 --> 00:32:40.910 I could prop them up. 00:32:40.910 --> 00:32:42.900 That's called a syncline. 00:32:42.900 --> 00:32:45.745 And if I put two ladders like this, if I'm really stupid and 00:32:45.745 --> 00:32:48.410 I fail physics, if I do this, they fall down. 00:32:48.410 --> 00:32:51.220 So this is called an anticline, OK? 00:32:51.220 --> 00:32:52.100 That's an anticline. 00:32:52.100 --> 00:32:53.350 This is a syncline. 00:32:57.380 --> 00:33:01.700 It's not a U-shape, or a hump, or something like that. 00:33:01.700 --> 00:33:02.620 This is 3091. 00:33:02.620 --> 00:33:03.740 This is a syncline. 00:33:03.740 --> 00:33:05.230 Synclinal coexistence curve. 00:33:05.230 --> 00:33:05.520 All right. 00:33:05.520 --> 00:33:06.620 So what's on here? 00:33:06.620 --> 00:33:08.960 What's this equilibrium, then? 00:33:08.960 --> 00:33:11.630 Well, the equilibrium must be this equals this. 00:33:11.630 --> 00:33:14.560 So that would be, in the case of the solid, it's the solid 00:33:14.560 --> 00:33:19.100 solution goes to alpha plus beta, or it could be the 00:33:19.100 --> 00:33:23.570 liquid goes to liquid 1 plus liquid 2. 00:33:23.570 --> 00:33:26.110 That's the equilibrium. 00:33:26.110 --> 00:33:28.550 You can think about it almost as a solubility. 00:33:28.550 --> 00:33:30.140 So let's start over here on the left. 00:33:30.140 --> 00:33:31.190 Let's pick a temperature. 00:33:31.190 --> 00:33:32.670 Let's call this T1. 00:33:32.670 --> 00:33:37.270 So I can put B into A, and I continue to get an all-solid 00:33:37.270 --> 00:33:40.060 solution, up to this concentration here. 00:33:40.060 --> 00:33:42.230 What happens at this concentration? 00:33:42.230 --> 00:33:44.050 I've hit a solubility limit. 00:33:44.050 --> 00:33:47.545 And if I try to put any more B into A, I get a tie line-- 00:33:50.220 --> 00:33:51.290 lever rule. 00:33:51.290 --> 00:33:54.210 In here is lever rule time, isn't it? 00:33:54.210 --> 00:33:56.780 Lever rule. p equals 2, OK? 00:33:56.780 --> 00:33:59.010 So it's solubility limits. 00:33:59.010 --> 00:34:00.260 Solubility limits. 00:34:02.550 --> 00:34:02.850 All right. 00:34:02.850 --> 00:34:06.820 So let's look at some examples. 00:34:06.820 --> 00:34:07.760 Oh, here's this one, actually. 00:34:07.760 --> 00:34:08.720 That's why I had a-- 00:34:08.720 --> 00:34:10.995 you know, if you go to lower temperature, gold, nickel-- 00:34:10.995 --> 00:34:12.520 look! 00:34:12.520 --> 00:34:14.250 They actually phase separate. 00:34:14.250 --> 00:34:15.060 That's shocking. 00:34:15.060 --> 00:34:18.120 I always find this one shocking, because you think 00:34:18.120 --> 00:34:20.610 gold, nickel, nice FCC metals, they should 00:34:20.610 --> 00:34:21.850 substitute for one another. 00:34:21.850 --> 00:34:22.435 Look what happens. 00:34:22.435 --> 00:34:25.760 If you start putting nickel into pure gold at 700 degrees, 00:34:25.760 --> 00:34:28.440 you get the 10 weight percent, you put any more in, boom. 00:34:28.440 --> 00:34:30.870 Right across here. 00:34:30.870 --> 00:34:32.840 So this is going to be two phase. 00:34:32.840 --> 00:34:35.870 So if you look at the solid, what's that 00:34:35.870 --> 00:34:37.650 going to look like? 00:34:37.650 --> 00:34:41.400 If I'm at, say, 30%, now I look underneath and I've got a 00:34:41.400 --> 00:34:44.030 polygrain system, and I'm going to have an alpha and a 00:34:44.030 --> 00:34:47.160 beta, and an alpha and a beta. 00:34:47.160 --> 00:34:49.850 I'm going to have two different grains. 00:34:49.850 --> 00:34:52.000 And now, what's the relative amount of alpha and the 00:34:52.000 --> 00:34:53.340 relative amount of beta? 00:34:53.340 --> 00:34:55.860 It's given by the lever rule. 00:34:55.860 --> 00:34:56.970 OK. 00:34:56.970 --> 00:34:58.340 Let's look at a few other examples. 00:34:58.340 --> 00:35:01.130 Here's hexane nitrobenzene. 00:35:01.130 --> 00:35:04.190 And so they've even put l-alpha, l-beta. 00:35:04.190 --> 00:35:05.270 They put the-- 00:35:05.270 --> 00:35:06.630 actually, that's probably a-- 00:35:06.630 --> 00:35:07.350 it's hard to read. 00:35:07.350 --> 00:35:09.980 But I think it's really an F, but it didn't come through 00:35:09.980 --> 00:35:13.040 very well, so it's the beta fraction, the alpha fraction. 00:35:13.040 --> 00:35:14.930 So you can see how you use the lever rule. 00:35:14.930 --> 00:35:16.430 So up here it's all p. 00:35:16.430 --> 00:35:19.000 That's the not pressure, that's my circle p. 00:35:19.000 --> 00:35:20.550 Single phase, two phase. 00:35:20.550 --> 00:35:23.820 Drop down to 290 degrees, it separates into two liquids. 00:35:23.820 --> 00:35:24.930 With the hexane-- 00:35:24.930 --> 00:35:26.730 with two liquids, you'll actually have them floating on 00:35:26.730 --> 00:35:28.600 top of one another, right? 00:35:28.600 --> 00:35:29.310 Well, maybe. 00:35:29.310 --> 00:35:31.840 Depending if the density difference is tiny, you might 00:35:31.840 --> 00:35:32.710 get a dispersion. 00:35:32.710 --> 00:35:34.390 I'll show you that in a second. 00:35:34.390 --> 00:35:34.670 All right. 00:35:34.670 --> 00:35:36.680 So p equals 2, lever rule. 00:35:36.680 --> 00:35:38.740 OK? 00:35:38.740 --> 00:35:40.320 Hexane nitrobenzene. 00:35:40.320 --> 00:35:40.940 Look at this one. 00:35:40.940 --> 00:35:42.010 This is surprising to me. 00:35:42.010 --> 00:35:44.020 Potassium chloride, sodium chloride. 00:35:44.020 --> 00:35:46.420 It's almost lenticular with a little bit of depression, but 00:35:46.420 --> 00:35:47.670 down here, it actually separates. 00:35:50.660 --> 00:35:51.930 This is polymer. 00:35:51.930 --> 00:35:53.840 It's a polystyrene, polybutadiene, 00:35:53.840 --> 00:35:56.460 depending on what the-- 00:35:56.460 --> 00:36:01.150 at low index, polymerization index, they mix. 00:36:01.150 --> 00:36:03.360 At high polymerization index, the two are mixing. 00:36:03.360 --> 00:36:05.020 You get two phase, single phase. 00:36:05.020 --> 00:36:09.040 Changes the mechanical properties, too, doesn't it? 00:36:09.040 --> 00:36:10.220 Now this one-- 00:36:10.220 --> 00:36:13.720 some systems actually have a lower critical point. 00:36:13.720 --> 00:36:14.800 Oh, I meant to tell you. 00:36:14.800 --> 00:36:17.570 You see, there's this temperature here. 00:36:17.570 --> 00:36:20.290 Above this temperature, they mix in all proportions. 00:36:20.290 --> 00:36:22.400 You can ever have phase separation. 00:36:22.400 --> 00:36:25.560 This is the maximum temperature at which you have 00:36:25.560 --> 00:36:26.980 no phase separation. 00:36:26.980 --> 00:36:32.030 So this is called the consolute temperature. 00:36:32.030 --> 00:36:35.070 And it's usually an upper consolute. 00:36:35.070 --> 00:36:36.570 The higher you go in temperature-- 00:36:36.570 --> 00:36:39.320 it's like saying, do you dissolve more sugar in cold 00:36:39.320 --> 00:36:41.010 water or warm water? 00:36:41.010 --> 00:36:43.270 You dissolve more sugar in warm water. 00:36:43.270 --> 00:36:45.200 And eventually, you get to a temperature high enough that 00:36:45.200 --> 00:36:47.270 you can mix in all proportions, right? 00:36:47.270 --> 00:36:48.540 That's the consolute. 00:36:48.540 --> 00:36:50.970 Some systems, for entropic reasons-- and again, if you 00:36:50.970 --> 00:36:53.870 take 560 or some of the other thermal classes, you'll 00:36:53.870 --> 00:36:57.010 understand this, but for entropic reasons, you actually 00:36:57.010 --> 00:37:00.710 have homogeneous solutions at low temperature, and at 00:37:00.710 --> 00:37:02.640 elevated temperature, you get phase separation. 00:37:02.640 --> 00:37:03.840 That's funny, isn't it. 00:37:03.840 --> 00:37:06.860 So this is water triethylamine, and they mix in 00:37:06.860 --> 00:37:09.810 all proportions at this zone here. 00:37:09.810 --> 00:37:12.460 And then above a certain-- it's called lower consolute 00:37:12.460 --> 00:37:13.290 temperature. 00:37:13.290 --> 00:37:15.060 It actually phase separates. 00:37:15.060 --> 00:37:15.700 Doesn't matter. 00:37:15.700 --> 00:37:20.120 All you care about is p equals 2, phase 00:37:20.120 --> 00:37:22.410 separation, lever rule. 00:37:22.410 --> 00:37:24.110 The rest is details. 00:37:24.110 --> 00:37:25.700 This is a real hoot. 00:37:25.700 --> 00:37:27.320 This is water nicotine. 00:37:27.320 --> 00:37:30.460 It has a lower consolute temperature and an upper 00:37:30.460 --> 00:37:32.180 consolute temperature. 00:37:32.180 --> 00:37:34.015 So it's got a solubility bubble. 00:37:36.760 --> 00:37:37.760 You see? 00:37:37.760 --> 00:37:39.350 Out here, things are soluble. 00:37:39.350 --> 00:37:41.190 In here, they're insoluble. 00:37:41.190 --> 00:37:42.490 So they are emissible. 00:37:42.490 --> 00:37:46.270 So we call this zone, this region here under the dome, so 00:37:46.270 --> 00:37:55.160 to speak, this it's called the miscibility gap, because 00:37:55.160 --> 00:37:57.620 things in there are not soluble in one another. 00:37:57.620 --> 00:37:59.890 But with nicotine, you have a lower consolute and an upper 00:37:59.890 --> 00:38:01.740 consolute, so you have a miscibility gap that's a 00:38:01.740 --> 00:38:04.470 complete ring. 00:38:04.470 --> 00:38:05.615 That's cool! 00:38:05.615 --> 00:38:07.780 I like this. 00:38:07.780 --> 00:38:08.000 All right. 00:38:08.000 --> 00:38:09.240 So now I'm going to do a little experiment. 00:38:09.240 --> 00:38:10.990 We have a few minutes, so I'm going to show you ouzo water. 00:38:10.990 --> 00:38:14.830 I'm going to mix it, and I'm going to actually mix ouzo and 00:38:14.830 --> 00:38:18.420 water, and go into the two phase regime, and then out. 00:38:18.420 --> 00:38:20.050 So this is what it is, all right? 00:38:20.050 --> 00:38:21.510 It's oily stuff, you know. 00:38:21.510 --> 00:38:23.920 If you're of Greek ancestry, you know what this stuff is. 00:38:23.920 --> 00:38:24.290 All right? 00:38:24.290 --> 00:38:26.810 But it's got licorice, it's got a fair bit of oil in it. 00:38:26.810 --> 00:38:29.010 So what I'm going to do, is I'm going to come in here, and 00:38:29.010 --> 00:38:31.650 I'm going to start adding ouzo to water. 00:38:31.650 --> 00:38:34.400 And they're both clear, colorless liquids. 00:38:34.400 --> 00:38:35.765 OK, Dave. Let's go to the-- 00:38:39.854 --> 00:38:40.590 All right. 00:38:40.590 --> 00:38:44.520 So what we're going to do-- this is distilled water. 00:38:44.520 --> 00:38:46.490 So I'm going to put some distilled water in here. 00:38:46.490 --> 00:38:47.980 A little bit of distilled water. 00:38:47.980 --> 00:38:49.020 And this is ouzo. 00:38:49.020 --> 00:38:50.770 It's clear and colorless. 00:38:50.770 --> 00:38:51.020 OK. 00:38:51.020 --> 00:38:53.142 Can we show you this? 00:38:53.142 --> 00:38:54.470 Let's do this. 00:38:54.470 --> 00:38:54.770 OK. 00:38:54.770 --> 00:38:58.060 Ouzo, it comes from Greece. 00:38:58.060 --> 00:38:59.030 All right. 00:38:59.030 --> 00:39:01.780 So it's also clear and colorless. 00:39:01.780 --> 00:39:02.660 That was the point. 00:39:02.660 --> 00:39:03.840 Not to show you the label. 00:39:03.840 --> 00:39:04.100 See? 00:39:04.100 --> 00:39:05.590 It's clear and colorless. 00:39:05.590 --> 00:39:07.800 So this is clear and colorless, and the water, as 00:39:07.800 --> 00:39:09.340 you know, is clear and colorless. 00:39:09.340 --> 00:39:10.560 So now what I'm going to do-- 00:39:10.560 --> 00:39:11.995 see, I don't have to wear a smock, 00:39:11.995 --> 00:39:13.430 or goggles, or anything. 00:39:13.430 --> 00:39:14.590 This is great. 00:39:14.590 --> 00:39:15.760 So what I'm going to do, is I'm going to add 00:39:15.760 --> 00:39:16.570 some of this stuff. 00:39:16.570 --> 00:39:17.820 Clear and colorless. 00:39:21.690 --> 00:39:22.040 OK. 00:39:22.040 --> 00:39:22.910 It's turned milky. 00:39:22.910 --> 00:39:24.300 Why has it turned milky? 00:39:24.300 --> 00:39:29.070 Because we've now crossed into here, and the second phase is 00:39:29.070 --> 00:39:29.890 coming out. 00:39:29.890 --> 00:39:32.830 But the density difference and surface tension differences 00:39:32.830 --> 00:39:37.470 are so slight, that instead of having the second phase float 00:39:37.470 --> 00:39:41.190 on the first phase, we have a dispersion, G. 00:39:41.190 --> 00:39:43.340 If you go to the dairy case, and you look at something 00:39:43.340 --> 00:39:46.160 called milk, you'll have the same thing. 00:39:46.160 --> 00:39:47.360 Why is milk milky? 00:39:47.360 --> 00:39:50.640 Because the fatty phase is a fine dispersion, and the 00:39:50.640 --> 00:39:54.480 particle sizes is dadadada, versus the wavelength of 00:39:54.480 --> 00:39:55.940 visible light, et cetera. 00:39:55.940 --> 00:40:00.070 Now if my phase diagram is correct, and I'm in here, if I 00:40:00.070 --> 00:40:03.310 keep adding ouzo, I should eventually emerge on this 00:40:03.310 --> 00:40:10.190 side, and instead of having a milky dispersion, I eventually 00:40:10.190 --> 00:40:13.240 should come here, and now I'll have a homogeneous, 00:40:13.240 --> 00:40:14.830 single-phase solution. 00:40:14.830 --> 00:40:17.300 But now it's going to be ouzo-rich, instead of 00:40:17.300 --> 00:40:18.550 water-rich. 00:40:20.310 --> 00:40:23.330 You never thought phase diagrams were interesting. 00:40:23.330 --> 00:40:24.580 You don't know. 00:40:29.660 --> 00:40:32.870 There we go. 00:40:32.870 --> 00:40:35.000 Je vous presente. 00:40:35.000 --> 00:40:36.350 There it is. 00:40:36.350 --> 00:40:39.430 So what we've done is, we've come across the thing. 00:40:39.430 --> 00:40:41.840 Yeah, that's good. 00:40:41.840 --> 00:40:43.300 Just put that there. 00:40:43.300 --> 00:40:48.670 Now, David, please, back to the slides. 00:40:48.670 --> 00:40:51.000 May I have the next slide, please? 00:40:51.000 --> 00:40:52.670 That's a joke. 00:40:52.670 --> 00:40:57.100 When you have these terrible speakers at conferences, they 00:40:57.100 --> 00:40:59.570 get up there, really nervous, and they stand up there, and 00:40:59.570 --> 00:41:01.180 the first thing they say is, may I have the 00:41:01.180 --> 00:41:02.730 first slide, please? 00:41:02.730 --> 00:41:04.970 That's sort of a gag among scientists. 00:41:04.970 --> 00:41:07.260 What's your opening statement? 00:41:07.260 --> 00:41:10.150 May I have the first slide, please? 00:41:10.150 --> 00:41:11.590 May I have the next slide, please? 00:41:11.590 --> 00:41:11.780 OK. 00:41:11.780 --> 00:41:13.240 So we've done this. 00:41:13.240 --> 00:41:14.940 All right. 00:41:14.940 --> 00:41:15.810 Now-- 00:41:15.810 --> 00:41:18.890 yeah, OK, this is just more. 00:41:18.890 --> 00:41:19.014 All right. 00:41:19.014 --> 00:41:20.390 So now I'm going to show you absinthe. 00:41:20.390 --> 00:41:21.460 Absinthe is the same thing. 00:41:21.460 --> 00:41:24.970 Absinthe also comes from the same family. 00:41:24.970 --> 00:41:28.020 And there's a little culture here. 00:41:28.020 --> 00:41:29.280 It contains wormwood. 00:41:29.280 --> 00:41:32.750 The wormwood was up at around 200, 250 parts per million. 00:41:32.750 --> 00:41:36.060 And what wormwood does, it's got a 00:41:36.060 --> 00:41:37.150 hormone they call thujone. 00:41:37.150 --> 00:41:40.900 And thujone antagonizes the gamma aminobutyric acid, which 00:41:40.900 --> 00:41:43.080 moderates firing of the neural synapses. 00:41:43.080 --> 00:41:46.440 Basically, we've got this GABA that regulates how-- our 00:41:46.440 --> 00:41:49.250 brains could work much faster than they do, 00:41:49.250 --> 00:41:51.880 but the GABA regulates. 00:41:51.880 --> 00:41:55.470 If GABA doesn't work, you can start moving so fast that you 00:41:55.470 --> 00:41:58.310 get muscle thing, and you get epileptic, is one example. 00:41:58.310 --> 00:42:02.050 But anyways, what it does, is if you drink this stuff, 00:42:02.050 --> 00:42:04.280 instead of being a stupid drunk, you become a very 00:42:04.280 --> 00:42:08.410 high-functioning, very alert drunk. 00:42:08.410 --> 00:42:10.470 And I'm going to show you what the consequence is in art. 00:42:10.470 --> 00:42:14.640 Anyways, the cultural piece here was that there was a 00:42:14.640 --> 00:42:19.430 destruction of the French wine industry in the 1800s due to a 00:42:19.430 --> 00:42:22.130 blight called Phylloxera. 00:42:22.130 --> 00:42:24.780 It's like a beetle, and it ate the vines. 00:42:24.780 --> 00:42:26.950 And in fact, the French wine industry was saved by the 00:42:26.950 --> 00:42:28.150 American wine industry. 00:42:28.150 --> 00:42:31.755 Vines from New York state were brought over, grafts were 00:42:31.755 --> 00:42:36.160 made, and virtually all French wine today is on American 00:42:36.160 --> 00:42:39.370 stock with the exception, occasionally you'll see 00:42:39.370 --> 00:42:40.650 something says vieille vin. 00:42:40.650 --> 00:42:41.460 Old vines. 00:42:41.460 --> 00:42:43.520 There was some areas that were spared. 00:42:43.520 --> 00:42:45.620 So what's that have to do with anything? 00:42:45.620 --> 00:42:48.860 It has to do with the fact that when the Phylloxera hit, 00:42:48.860 --> 00:42:52.030 the price of wine went very high, and the people at the 00:42:52.030 --> 00:42:55.230 bottom of the socioeconomic ladder couldn't afford wine. 00:42:55.230 --> 00:42:57.010 So they turn to absinthe. 00:42:57.010 --> 00:42:59.610 Absinthe was easily produced. 00:42:59.610 --> 00:43:02.600 Thirty years later, when the vines come back, the French 00:43:02.600 --> 00:43:05.350 wine industry wants to recapture the market. 00:43:05.350 --> 00:43:07.920 So there's a Faustian bargain between the French wine 00:43:07.920 --> 00:43:12.160 industry and the Women's Temperance Union to try to 00:43:12.160 --> 00:43:14.530 disparage absinthe. 00:43:14.530 --> 00:43:17.620 And there were a few major show trials that involved 00:43:17.620 --> 00:43:20.750 vicious murders in which it was alleged that the killer 00:43:20.750 --> 00:43:23.120 was deranged on absinthe. 00:43:23.120 --> 00:43:26.870 And with this, they slandered the name of absinthe so badly 00:43:26.870 --> 00:43:29.570 that it was eventually banned and literally 00:43:29.570 --> 00:43:30.990 taken off the market. 00:43:30.990 --> 00:43:32.000 I mean-- 00:43:32.000 --> 00:43:34.780 you know, we had the Rosalind Franklin commentary a few 00:43:34.780 --> 00:43:35.240 lectures ago. 00:43:35.240 --> 00:43:37.610 I hope I never read about you doing something like this in 00:43:37.610 --> 00:43:39.450 order to help your start-up company 00:43:39.450 --> 00:43:40.580 take over market share. 00:43:40.580 --> 00:43:43.880 That's not the way you're supposed to do it. 00:43:43.880 --> 00:43:44.650 Anyway, so what-- 00:43:44.650 --> 00:43:46.030 now, how did they drink it? 00:43:46.030 --> 00:43:47.940 They drank it by mixing-- 00:43:47.940 --> 00:43:50.050 so it's now back, but it's got very low levels 00:43:50.050 --> 00:43:51.420 of thujone, so it's-- 00:43:51.420 --> 00:43:53.240 David, may we go to this? 00:43:53.240 --> 00:43:55.200 So we're going to make a mix called the louche. 00:43:55.200 --> 00:43:56.090 It's a-- 00:43:56.090 --> 00:43:57.730 OK, here it is. 00:43:57.730 --> 00:43:59.005 And this stuff here is beautiful. 00:44:01.550 --> 00:44:04.950 Because it's a green color, a soft green color. 00:44:04.950 --> 00:44:06.710 And the French even have a name for it. 00:44:06.710 --> 00:44:09.660 They call it the green fairy, la fee verte. 00:44:09.660 --> 00:44:13.620 So this is what absinthe looks like. 00:44:13.620 --> 00:44:14.520 Beautiful. 00:44:14.520 --> 00:44:15.280 Very nice. 00:44:15.280 --> 00:44:17.950 And it's got the same kind of licorice smell to it. 00:44:17.950 --> 00:44:22.590 And so you make the louche by one part absinthe and five 00:44:22.590 --> 00:44:23.210 parts water. 00:44:23.210 --> 00:44:27.030 So this, at no upcharge, you get this glass. 00:44:27.030 --> 00:44:31.210 It's a beautiful piece of, you know, late 00:44:31.210 --> 00:44:32.860 Belle Epoque glassware. 00:44:32.860 --> 00:44:34.980 And the interesting thing is, these people were absolutely 00:44:34.980 --> 00:44:37.120 crazy, scientifically. 00:44:37.120 --> 00:44:40.180 And so what they did is, the markings on this glass are 00:44:40.180 --> 00:44:44.210 such that if you put absinthe up to this ring here, and then 00:44:44.210 --> 00:44:47.060 you put water the rest of the way, you get exactly the five 00:44:47.060 --> 00:44:49.220 to one ratio for louche. 00:44:49.220 --> 00:44:51.320 So you don't even have to measure. 00:44:51.320 --> 00:44:53.930 You just put like so. 00:44:53.930 --> 00:44:54.240 OK. 00:44:54.240 --> 00:44:55.060 Let's see. 00:44:55.060 --> 00:44:55.930 I'm going to get this right! 00:44:55.930 --> 00:44:57.180 It's science. 00:44:58.950 --> 00:45:01.610 Here's our distilled water. 00:45:01.610 --> 00:45:04.030 You see how it's milky? 00:45:04.030 --> 00:45:05.030 So there's the louche. 00:45:05.030 --> 00:45:11.390 And if you wanted to be a real hipster, you had this special 00:45:11.390 --> 00:45:13.320 Belle Epoque spoon. 00:45:13.320 --> 00:45:17.500 And what you'd put on top of this would be a sugar cube. 00:45:17.500 --> 00:45:19.400 You know, this is how it was done. 00:45:19.400 --> 00:45:20.960 You have to know some culture. 00:45:20.960 --> 00:45:21.500 You don't know. 00:45:21.500 --> 00:45:23.200 You've led sheltered lives. 00:45:23.200 --> 00:45:24.380 You pour it through here, like this. 00:45:24.380 --> 00:45:26.570 So now I'm going to show you the art. 00:45:26.570 --> 00:45:31.820 So David, may we cut to the slides again? 00:45:31.820 --> 00:45:35.110 So there's the louche. 00:45:35.110 --> 00:45:35.390 All right. 00:45:35.390 --> 00:45:36.150 So here's the poster. 00:45:36.150 --> 00:45:36.710 Here's the man. 00:45:36.710 --> 00:45:40.820 He's pouring the water through the slotted spoon with the 00:45:40.820 --> 00:45:43.240 thing, and there's a very well-to-do lady, you can tell, 00:45:43.240 --> 00:45:45.470 she's got a beautiful hat, and she's well-dressed. 00:45:45.470 --> 00:45:48.610 And he's inviting her to join him for a glass of absinthe. 00:45:48.610 --> 00:45:50.200 L'absinthe oxygenee. 00:45:50.200 --> 00:45:51.230 That's the name of the company. 00:45:51.230 --> 00:45:52.940 The oxygenated absinthe. 00:45:52.940 --> 00:45:53.800 C'est ma sante. 00:45:53.800 --> 00:45:55.050 This is my health. 00:45:58.120 --> 00:46:01.490 Van Gogh painted this. 00:46:01.490 --> 00:46:02.320 This is Picasso. 00:46:02.320 --> 00:46:03.250 The absinthe drinker. 00:46:03.250 --> 00:46:05.050 There's the absinthe again. 00:46:05.050 --> 00:46:09.040 This is Picasso after many absinthes. 00:46:09.040 --> 00:46:12.090 You can see the slotted spoon and the sugar cube. 00:46:12.090 --> 00:46:13.550 What else is there? 00:46:13.550 --> 00:46:16.750 That's up to you. 00:46:16.750 --> 00:46:17.050 All right. 00:46:17.050 --> 00:46:19.740 When you saw Moulin Rouge, you may not have known all of this 00:46:19.740 --> 00:46:20.580 cultural history. 00:46:20.580 --> 00:46:24.040 So now let's take a look at what's going on here. 00:46:24.040 --> 00:46:26.890 There's the absinthe, and I think we've got a little-- 00:46:26.890 --> 00:46:28.838 [VIDEO PLAYBACK] 00:46:28.838 --> 00:46:32.247 -I don't even know if I am a true Bohemian revolutionary. 00:46:32.247 --> 00:46:33.840 -Do you believe in beauty? 00:46:33.840 --> 00:46:34.665 -Yes. 00:46:34.665 --> 00:46:35.130 -Freedom? 00:46:35.130 --> 00:46:35.786 -Yes, of course. 00:46:35.786 --> 00:46:36.780 -Truth? 00:46:36.780 --> 00:46:36.960 -Yes. 00:46:36.960 --> 00:46:39.170 -Love? 00:46:39.170 --> 00:46:39.970 -Love? 00:46:39.970 --> 00:46:41.086 Love. 00:46:41.086 --> 00:46:43.245 Above all things, I believe in love. 00:46:43.245 --> 00:46:45.320 Love is like oxygen. 00:46:45.320 --> 00:46:46.570 Love is a many-splendored thing-- 00:46:51.866 --> 00:46:52.580 [END VIDEO PLAYBACK] 00:46:52.580 --> 00:46:55.020 Love is like oxygen. 00:46:55.020 --> 00:46:56.270 Chemistry is everywhere! 00:47:00.400 --> 00:47:02.110 All right, so this is what happens eventually. 00:47:02.110 --> 00:47:03.720 This is the poster. 00:47:03.720 --> 00:47:04.950 This is from Switzerland. 00:47:04.950 --> 00:47:06.560 October 7, 1910. 00:47:06.560 --> 00:47:08.350 Gentleman, This Is the Hour! 00:47:08.350 --> 00:47:11.020 And there's the clergyman with the Bible, and there's the 00:47:11.020 --> 00:47:11.900 green fairy. 00:47:11.900 --> 00:47:14.030 And she has a wand. 00:47:14.030 --> 00:47:16.640 She's been stabbed, but she's lying here with a wand. 00:47:16.640 --> 00:47:19.440 The wand is an opalescent wand, because this stuff is 00:47:19.440 --> 00:47:20.220 opalescent. 00:47:20.220 --> 00:47:22.390 Last thing I'll show you is some really, really cool 00:47:22.390 --> 00:47:24.720 chemistry that you must remember. 00:47:24.720 --> 00:47:26.360 When Toulouse-Lautrec drank-- 00:47:26.360 --> 00:47:30.160 let's go back, David, to the thing. 00:47:30.160 --> 00:47:33.320 So when Toulouse-Lautrec drank absinthe, and he drank lots of 00:47:33.320 --> 00:47:36.370 it, he didn't like the milky color. 00:47:36.370 --> 00:47:38.910 So he wanted to make the milky color disappear. 00:47:38.910 --> 00:47:41.330 So I'm in the two-phase regime, and 00:47:41.330 --> 00:47:42.760 I've got an oily phase. 00:47:42.760 --> 00:47:44.910 And so how do I get rid of the oily phase? 00:47:44.910 --> 00:47:46.800 What he did is he added cognac 00:47:46.800 --> 00:47:48.200 And why did he add cognac? 00:47:48.200 --> 00:47:52.550 Not because he was a hard-drinking alcoholic. 00:47:52.550 --> 00:47:56.355 It's because if you've got a fat phase here, and you've got 00:47:56.355 --> 00:47:58.500 an aqueous phase here, and if you add 00:47:58.500 --> 00:48:00.030 alcohol, you've got CH3CH2OH. 00:48:04.130 --> 00:48:09.680 This can bond to the water by a hydrogen bond, and this 00:48:09.680 --> 00:48:12.330 aliphatic tail can stab the fat and 00:48:12.330 --> 00:48:13.460 bring them into solution. 00:48:13.460 --> 00:48:15.010 That's why you have these recipes. 00:48:15.010 --> 00:48:17.810 Do you ever wonder why the recipe says, add brandy, or 00:48:17.810 --> 00:48:20.350 add this, and then two steps later, it says flame? 00:48:20.350 --> 00:48:22.010 You say, geez, I just put the brandy in, now 00:48:22.010 --> 00:48:23.380 it's vaporizing away. 00:48:23.380 --> 00:48:24.370 Isn't that kind of stupid? 00:48:24.370 --> 00:48:25.630 No, it's not! 00:48:25.630 --> 00:48:26.410 This is what you're doing. 00:48:26.410 --> 00:48:27.360 You're cosolvating. 00:48:27.360 --> 00:48:29.650 If you're ever making a cream sauce or something, and all of 00:48:29.650 --> 00:48:31.570 a sudden, everything just curdles? 00:48:31.570 --> 00:48:32.350 First you scream. 00:48:32.350 --> 00:48:33.010 You go, ahhh! 00:48:33.010 --> 00:48:34.290 Phase separation. 00:48:34.290 --> 00:48:36.910 The second thing you do, is you get some of this, and you 00:48:36.910 --> 00:48:37.960 cosolvate it. 00:48:37.960 --> 00:48:38.940 All right. 00:48:38.940 --> 00:48:40.440 So let's see what Lautrec did. 00:48:40.440 --> 00:48:42.286 Lautrec-- 00:48:42.286 --> 00:48:44.550 I might have to dilute the volume here. 00:48:44.550 --> 00:48:45.600 We've got quite a lot in here. 00:48:45.600 --> 00:48:47.230 So just to make the point. 00:48:47.230 --> 00:48:49.520 So here's the louche, ad now we're going to add cognac. 00:48:49.520 --> 00:48:51.720 He called this drink, Le Tremblement de Terre. 00:48:51.720 --> 00:48:54.370 The earthquake. 00:48:54.370 --> 00:48:57.680 He had a walking stick a meter long that was hollow, and it 00:48:57.680 --> 00:48:58.470 always had this in it. 00:48:58.470 --> 00:49:00.120 Look! 00:49:00.120 --> 00:49:01.010 Look at that. 00:49:01.010 --> 00:49:02.120 Isn't that something? 00:49:02.120 --> 00:49:07.290 So now it's this beautiful blonde, golden color. 00:49:07.290 --> 00:49:09.230 It's clear. 00:49:09.230 --> 00:49:14.270 So this is all phase separation and so on. 00:49:14.270 --> 00:49:15.910 At the end, it's all about chemistry. 00:49:15.910 --> 00:49:16.210 All right. 00:49:16.210 --> 00:49:18.830 We'll see you on Wednesday for our wrap-up. 00:49:18.830 --> 00:49:20.080 Good.