1 00:00:00,030 --> 00:00:02,400 The following content is provided under a Creative 2 00:00:02,400 --> 00:00:03,830 Commons license. 3 00:00:03,830 --> 00:00:06,850 Your support will help MIT OpenCourseWare continue to 4 00:00:06,850 --> 00:00:10,510 offer high-quality educational resources for free. 5 00:00:10,510 --> 00:00:13,390 To make a donation or view additional materials from 6 00:00:13,390 --> 00:00:17,490 hundreds of MIT courses, visit MIT OpenCourseWare at 7 00:00:17,490 --> 00:00:18,740 ocw.mit.edu. 8 00:00:21,050 --> 00:00:21,470 PROFESSOR: OK. 9 00:00:21,470 --> 00:00:22,720 So. 10 00:00:24,740 --> 00:00:27,590 Last day we started looking at phase diagrams, and we looked 11 00:00:27,590 --> 00:00:31,780 at unary phase diagrams, one component systems, and one 12 00:00:31,780 --> 00:00:35,060 component system P versus T, pressure versus temperature. 13 00:00:35,060 --> 00:00:39,130 And this is the situation for water. 14 00:00:39,130 --> 00:00:42,370 Water is an exception, because it's got this negative solid 15 00:00:42,370 --> 00:00:47,330 equals liquid coexistence curve, but otherwise, you have 16 00:00:47,330 --> 00:00:50,970 large, single-phase regions here, which I've designated 17 00:00:50,970 --> 00:00:55,100 circle p equals 1, and then along these lines, we have 18 00:00:55,100 --> 00:00:56,310 equilibria. 19 00:00:56,310 --> 00:00:59,230 So this is liquid goes to vapor, this is solid goes to 20 00:00:59,230 --> 00:01:01,410 liquid, this is solid goes to vapor. 21 00:01:01,410 --> 00:01:05,640 And we know that for water, if we take the 1 atmosphere, if 22 00:01:05,640 --> 00:01:08,800 this is pressure in atmospheres, the 1 atmosphere 23 00:01:08,800 --> 00:01:13,490 isobar, then that would put this point at 100 degrees 24 00:01:13,490 --> 00:01:16,470 Celsius, and this point at 0 Celsius. 25 00:01:16,470 --> 00:01:21,420 And then we have the triple point, which is solid equals 26 00:01:21,420 --> 00:01:27,620 liquid equals vapor at 0.01 degrees C, and p equals, I 27 00:01:27,620 --> 00:01:31,920 think it was 4.58 millimeters of mercury. 28 00:01:31,920 --> 00:01:35,030 So that's the triple point. 29 00:01:35,030 --> 00:01:39,720 And we looked at a variety of other one-component phase 30 00:01:39,720 --> 00:01:44,670 diagrams, and I think we came to a pretty good 31 00:01:44,670 --> 00:01:46,370 understanding. 32 00:01:46,370 --> 00:01:48,540 And then up here, we have the supercritical fluids. 33 00:01:48,540 --> 00:01:50,430 So I've got a break in the line here. 34 00:01:50,430 --> 00:01:55,640 And for water, you reach supercriticality at 374 35 00:01:55,640 --> 00:02:03,230 degrees Celsius, and up here at 218 atmospheres. 36 00:02:03,230 --> 00:02:05,990 So these are not phenomenal, these are not geological 37 00:02:05,990 --> 00:02:07,630 pressures at all. 38 00:02:07,630 --> 00:02:11,530 And so that's if we want to the decaffeinating of 39 00:02:11,530 --> 00:02:12,440 coffee and so on. 40 00:02:12,440 --> 00:02:14,960 And so what happens here, is you have a highly compressed 41 00:02:14,960 --> 00:02:18,410 vapor or a highly rarefied liquid, and you end up with 42 00:02:18,410 --> 00:02:21,690 solubilizing power of a liquid, but transport 43 00:02:21,690 --> 00:02:22,720 properties of a gas. 44 00:02:22,720 --> 00:02:25,700 So this stuff has really good diffusivity. 45 00:02:25,700 --> 00:02:28,880 So it can penetrate into interstices and do its work 46 00:02:28,880 --> 00:02:31,220 very quickly, to say nothing of the fact that you're up at 47 00:02:31,220 --> 00:02:34,760 374 degrees Celsius or higher. 48 00:02:34,760 --> 00:02:37,130 So today what I want to do, is I want to look at 49 00:02:37,130 --> 00:02:44,280 two-component systems. So component number is circle c, 50 00:02:44,280 --> 00:02:45,540 c equals 2. 51 00:02:45,540 --> 00:02:48,610 So that means now I have to deal with pressure, 52 00:02:48,610 --> 00:02:52,240 temperature, and lowercase c is composition. 53 00:02:52,240 --> 00:02:55,070 I want to know how things vary with composition. 54 00:02:55,070 --> 00:02:56,180 So let me give you an example. 55 00:02:56,180 --> 00:02:59,010 Suppose I have two substances, A and B. 56 00:02:59,010 --> 00:03:02,820 So here's substance A, and I've got its one-component 57 00:03:02,820 --> 00:03:03,620 phase diagram. 58 00:03:03,620 --> 00:03:07,670 And in this case, I'm going to put solid-liquid vapor in the 59 00:03:07,670 --> 00:03:10,830 conventional setting, where the solid-liquid line is-- 60 00:03:10,830 --> 00:03:13,140 the coexistence curve has a positive slope. 61 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 62 00:03:16,690 --> 00:03:20,450 got its solid-liquid coexistence curve, and so 63 00:03:20,450 --> 00:03:24,120 we've got its melting point, and whatever. 64 00:03:24,120 --> 00:03:26,210 So now the question I want to ask is, what happens 65 00:03:26,210 --> 00:03:28,390 if I mix A and B? 66 00:03:28,390 --> 00:03:32,790 And let's just say, here's the melting point of A, so this is 67 00:03:32,790 --> 00:03:35,380 at p equals 1 atmosphere. 68 00:03:35,380 --> 00:03:37,130 And here's the melting point of B. 69 00:03:37,130 --> 00:03:39,450 And I want to ask the question, how does the melting 70 00:03:39,450 --> 00:03:41,890 point of the mixture vary? 71 00:03:41,890 --> 00:03:45,020 So let's say I'm going to connect these, and I want to 72 00:03:45,020 --> 00:03:48,170 ask, what happens if I've got an AB mixture? 73 00:03:48,170 --> 00:03:50,240 So I'm going to put lowercase c here, which is 74 00:03:50,240 --> 00:03:51,560 concentration. 75 00:03:51,560 --> 00:03:54,320 So at the one end, I've got 100% A, and over here, I've 76 00:03:54,320 --> 00:03:57,130 got 100% B, and I know those melting points. 77 00:03:57,130 --> 00:03:59,040 Question is, what happens when I mix them? 78 00:03:59,040 --> 00:04:01,180 Does the melting point-- is it just a straight line? 79 00:04:01,180 --> 00:04:02,770 Is it a linear variation? 80 00:04:02,770 --> 00:04:04,160 Do you go through a local maximum? 81 00:04:04,160 --> 00:04:06,180 Do you go through a local minimum? 82 00:04:06,180 --> 00:04:07,240 Or do you go wild? 83 00:04:07,240 --> 00:04:08,560 I mean, what happens? 84 00:04:08,560 --> 00:04:11,620 So a question you might ask is, suppose I made a 50-50 85 00:04:11,620 --> 00:04:15,530 alloy of 50% A and 50% B. 86 00:04:15,530 --> 00:04:18,660 If I knew the end-member melting points, could I 87 00:04:18,660 --> 00:04:19,850 predict this? 88 00:04:19,850 --> 00:04:21,870 Or if not, do I have an archive? 89 00:04:21,870 --> 00:04:24,920 Remember the phase diagram compendium is an archive. 90 00:04:24,920 --> 00:04:27,170 What is the value of the melting 91 00:04:27,170 --> 00:04:30,320 point at 50-50 or 75-25? 92 00:04:30,320 --> 00:04:32,400 So that's the question I want to ask. 93 00:04:32,400 --> 00:04:35,900 Now this is getting really messy, because now I have to 94 00:04:35,900 --> 00:04:41,320 plot pressure, and I have to plot temperature, and I have 95 00:04:41,320 --> 00:04:43,720 to plot composition. 96 00:04:43,720 --> 00:04:46,000 So this is really crazy, right? 97 00:04:46,000 --> 00:04:48,870 I've got pressure, and I'm going to have composition 98 00:04:48,870 --> 00:04:51,020 here, and I'm going to have to have now a third 99 00:04:51,020 --> 00:04:52,020 axis, aren't I? 100 00:04:52,020 --> 00:04:53,710 I'm going to have to have a third axis. 101 00:04:53,710 --> 00:04:55,230 I'm going to need a temperature axis. 102 00:04:55,230 --> 00:04:57,700 And I've got to make a three-dimensional drawing. 103 00:04:57,700 --> 00:04:59,370 And this is messy. 104 00:04:59,370 --> 00:05:07,730 But we're in luck, because 3091 is solid state chemistry. 105 00:05:07,730 --> 00:05:10,750 So as solid state chemists, we're more interested in what 106 00:05:10,750 --> 00:05:12,480 happens in the solid here. 107 00:05:12,480 --> 00:05:15,080 Now, I've drawn these lines with a slope, but they're 108 00:05:15,080 --> 00:05:16,370 really not to scale. 109 00:05:16,370 --> 00:05:20,140 It turns out that, you know, you can move 10,000 feet up or 110 00:05:20,140 --> 00:05:24,280 down in the atmosphere and have a huge variation in the 111 00:05:24,280 --> 00:05:27,100 boiling point because this line is shallow. 112 00:05:27,100 --> 00:05:29,360 But this line is virtually straight up and down. 113 00:05:29,360 --> 00:05:32,170 You have to go to geological pressures to change the 114 00:05:32,170 --> 00:05:34,160 melting point very much. 115 00:05:34,160 --> 00:05:38,370 And so, as a result, this is almost insensitive to 116 00:05:38,370 --> 00:05:40,900 pressure, to first order, right? 117 00:05:40,900 --> 00:05:48,380 So we can say solid equals liquid is almost insensitive 118 00:05:48,380 --> 00:05:55,790 to pressure, whereas liquid equals vapor is very sensitive 119 00:05:55,790 --> 00:05:57,760 very sensitive to pressure. 120 00:05:57,760 --> 00:06:00,260 But we don't care about this so much. 121 00:06:00,260 --> 00:06:02,110 So what I'm going to do is throw it away. 122 00:06:02,110 --> 00:06:06,990 I'm going to throw it away, and just say, let's look at 123 00:06:06,990 --> 00:06:10,120 just T versus C. 124 00:06:10,120 --> 00:06:13,490 Temperature versus composition on the strength of the fact 125 00:06:13,490 --> 00:06:18,800 that the melting point and all of these things are mildly 126 00:06:18,800 --> 00:06:20,440 dependent on pressure. 127 00:06:20,440 --> 00:06:21,440 All right. 128 00:06:21,440 --> 00:06:23,640 So now I'm going to give you three different types. 129 00:06:23,640 --> 00:06:26,180 There's many, many different types of binary phase diagram. 130 00:06:26,180 --> 00:06:28,420 So now we're going to be looking at C equals 2. 131 00:06:28,420 --> 00:06:32,210 So instead of a unary, this is going to be called binary. 132 00:06:32,210 --> 00:06:36,330 Binary phase diagrams. And they come in all shapes and 133 00:06:36,330 --> 00:06:38,720 sizes, but they can pretty much be 134 00:06:38,720 --> 00:06:40,970 classified in several bins. 135 00:06:40,970 --> 00:06:43,550 And I've made the classification. 136 00:06:43,550 --> 00:06:51,990 So classify binary phase diagrams 137 00:06:51,990 --> 00:06:55,252 according to their bonding. 138 00:06:55,252 --> 00:06:58,360 It all comes back electronic structure and bonding. 139 00:06:58,360 --> 00:07:02,810 Vary by bonding. 140 00:07:02,810 --> 00:07:04,860 Because bonding, then, ultimately indicates 141 00:07:04,860 --> 00:07:06,670 solubility, and that's what we're looking at here. 142 00:07:06,670 --> 00:07:09,640 We're going to look at how well A dissolves into B, and 143 00:07:09,640 --> 00:07:11,540 how well B dissolves into A. 144 00:07:11,540 --> 00:07:12,790 That dictates solubility. 145 00:07:15,610 --> 00:07:17,630 So it all comes full circle. 146 00:07:17,630 --> 00:07:21,830 So I've made this up. 147 00:07:21,830 --> 00:07:23,080 You're now going to find this in the book. 148 00:07:23,080 --> 00:07:27,800 So I just decided, for ease of teaching 3091, is I'm going to 149 00:07:27,800 --> 00:07:29,120 just give the different types. 150 00:07:29,120 --> 00:07:31,330 And so I call them type one, type two, and type three. 151 00:07:31,330 --> 00:07:32,830 You're not going to find that in the books. 152 00:07:32,830 --> 00:07:35,010 I made that up, because it's simple. 153 00:07:35,010 --> 00:07:35,820 So type one. 154 00:07:35,820 --> 00:07:38,850 What's type one binary phase diagram, according to me? 155 00:07:38,850 --> 00:07:40,100 What is the type one? 156 00:07:40,100 --> 00:07:42,040 It means complete solubility. 157 00:07:46,790 --> 00:07:50,460 So A and B are completely soluble in one another as 158 00:07:50,460 --> 00:07:51,710 solid and liquids. 159 00:07:56,240 --> 00:07:57,780 That's the first thing that you'll see on a 160 00:07:57,780 --> 00:07:59,290 type one phase diagram. 161 00:07:59,290 --> 00:08:03,360 And the second one is, a change of state is present. 162 00:08:03,360 --> 00:08:06,160 And you know the only change of state we care about here is 163 00:08:06,160 --> 00:08:07,550 solid goes to liquid. 164 00:08:07,550 --> 00:08:10,835 So we're going to show solid goes to liquid, and the thing 165 00:08:10,835 --> 00:08:15,360 is totally, as they say in California, totally soluble as 166 00:08:15,360 --> 00:08:16,660 liquids and solids. 167 00:08:16,660 --> 00:08:20,120 Now, here's some bonding rules that you can think about. 168 00:08:20,120 --> 00:08:22,850 So what would be the characteristics of two 169 00:08:22,850 --> 00:08:25,900 substances A and B that would give complete solid 170 00:08:25,900 --> 00:08:26,880 solubility? 171 00:08:26,880 --> 00:08:31,010 Well, one thing is they'd have to have identical crystal 172 00:08:31,010 --> 00:08:32,320 structures. 173 00:08:32,320 --> 00:08:34,280 That would heighten the chances of this. 174 00:08:34,280 --> 00:08:37,780 Identical crystal structures. 175 00:08:37,780 --> 00:08:40,480 So if they're both FCC metals, you've got a better chance of 176 00:08:40,480 --> 00:08:45,890 making an infinite variation in solution composition than 177 00:08:45,890 --> 00:08:49,080 if one is an FCC metal and the other is a BCC metal because 178 00:08:49,080 --> 00:08:52,160 FCC will just sit on the lattice site. 179 00:08:52,160 --> 00:08:53,850 But there's more fine structures. 180 00:08:53,850 --> 00:09:00,620 Second one is similar atomic volumes. 181 00:09:00,620 --> 00:09:03,370 So if we're going to have a substitutional solid solution, 182 00:09:03,370 --> 00:09:05,950 let's make sure we're replacing oranges with 183 00:09:05,950 --> 00:09:09,360 oranges, and not trying to put a grapefruit on a site that 184 00:09:09,360 --> 00:09:11,405 normally is occupied by a lemon, because there's going 185 00:09:11,405 --> 00:09:13,460 to be a size restriction there. 186 00:09:13,460 --> 00:09:16,100 And the third thing is, even if they have identical crystal 187 00:09:16,100 --> 00:09:19,740 structures and similar atomic volumes, you can still run 188 00:09:19,740 --> 00:09:22,870 into trouble with respect to complete solid solubility if 189 00:09:22,870 --> 00:09:26,910 you have a large variation in electronegativity. 190 00:09:26,910 --> 00:09:28,500 And I'll show you an example of that. 191 00:09:28,500 --> 00:09:30,090 So if you have a small difference in 192 00:09:30,090 --> 00:09:32,980 electronegativity, it means there's a low propensity for 193 00:09:32,980 --> 00:09:37,410 polarity, and ultimately no chance of electron transfer. 194 00:09:37,410 --> 00:09:39,510 So I think it's pretty cool. 195 00:09:39,510 --> 00:09:41,930 So I wrote those down, but was disappointed to learn that for 196 00:09:41,930 --> 00:09:45,870 metals, they were enunciated about 75 years ago by the 197 00:09:45,870 --> 00:09:47,910 British metallurgist Hume-Rothery. 198 00:09:47,910 --> 00:09:50,560 So I can't take credit for this. 199 00:09:50,560 --> 00:09:51,420 This is one name. 200 00:09:51,420 --> 00:09:53,170 It's one of these hyphenated British names. 201 00:09:53,170 --> 00:09:57,090 He's Sir da-da-da-da Hume-Rothery. 202 00:09:57,090 --> 00:09:59,590 So he has the Hume-Rothery Rule. 203 00:09:59,590 --> 00:10:05,590 And he called such systems that mix as binaries forming 204 00:10:05,590 --> 00:10:11,860 isomorphous, meaning they have the same structure. 205 00:10:11,860 --> 00:10:16,010 So let's take a look at the prototypical isomorphous phase 206 00:10:16,010 --> 00:10:18,010 diagram, and it looks like this. 207 00:10:18,010 --> 00:10:20,860 We're plotting temperature versus composition. 208 00:10:20,860 --> 00:10:22,750 We threw away the pressure coordinate. 209 00:10:22,750 --> 00:10:25,770 So I got pure A on the left, pure B on the right. 210 00:10:25,770 --> 00:10:28,570 Little c is concentration, so it varies from 211 00:10:28,570 --> 00:10:31,210 100% A to 100% B. 212 00:10:31,210 --> 00:10:34,370 And the vertical axis is temperature. 213 00:10:34,370 --> 00:10:37,850 So one extreme, I've got the melting point-- 214 00:10:37,850 --> 00:10:40,270 this is a melting point of pure A. 215 00:10:40,270 --> 00:10:41,980 And at the other extreme, I've got the melting 216 00:10:41,980 --> 00:10:44,020 point of pure B. 217 00:10:47,040 --> 00:10:47,775 So that, we know. 218 00:10:47,775 --> 00:10:51,200 And now the question is, how does melting point vary as a 219 00:10:51,200 --> 00:10:52,520 function of composition? 220 00:10:52,520 --> 00:10:58,540 And for an isomorphous phase diagram, it looks like this: 221 00:10:58,540 --> 00:11:01,000 lens-shaped. 222 00:11:01,000 --> 00:11:05,210 Up here is all liquid. 223 00:11:05,210 --> 00:11:07,550 You see A and B mix in all proportions. 224 00:11:07,550 --> 00:11:09,020 And down here is all solid. 225 00:11:12,730 --> 00:11:17,410 And furthermore, it's an all-liquid solution. 226 00:11:17,410 --> 00:11:17,890 It's a mixture. 227 00:11:17,890 --> 00:11:19,660 And this is an all-solid solution. 228 00:11:22,980 --> 00:11:28,940 And then comes the piece that if you take enough 229 00:11:28,940 --> 00:11:30,900 thermodynamics, you'll be able to rationalize. 230 00:11:30,900 --> 00:11:33,520 I'm simply going to tell you without proof that when you 231 00:11:33,520 --> 00:11:38,800 have a multicomponent system, when c is greater than 1-- so 232 00:11:38,800 --> 00:11:40,090 we're in that situation. 233 00:11:40,090 --> 00:11:41,840 Now, c is 2. 234 00:11:41,840 --> 00:11:52,160 When c is greater than 1, it is impossible to move from one 235 00:11:52,160 --> 00:11:53,880 field, up here, this is-- 236 00:11:53,880 --> 00:11:55,840 I'd better put the label on it-- this is a 237 00:11:55,840 --> 00:11:57,390 single-phase field. 238 00:11:57,390 --> 00:12:01,970 So up here, p equals 1, because it's homogeneous 239 00:12:01,970 --> 00:12:04,580 liquid solution, p equals 1. 240 00:12:04,580 --> 00:12:06,050 When you're in pure materials, you can go 241 00:12:06,050 --> 00:12:07,140 from solid to liquid. 242 00:12:07,140 --> 00:12:09,240 But when you're in a two-component system, you 243 00:12:09,240 --> 00:12:12,770 cannot move from one single-phase field to a second 244 00:12:12,770 --> 00:12:14,700 single-phase field without moving 245 00:12:14,700 --> 00:12:16,820 through a two-phase field. 246 00:12:16,820 --> 00:12:22,300 And we'll get to that, what it means to move from one field 247 00:12:22,300 --> 00:12:32,860 of p equals 1 to another field of p equals 1 requires 248 00:12:32,860 --> 00:12:45,270 traverse or transit across a field of p equals 2. 249 00:12:45,270 --> 00:12:47,360 And so what's in here has to be the end member. 250 00:12:47,360 --> 00:12:50,970 So this must be liquid plus solid. 251 00:12:50,970 --> 00:12:54,080 So I'm going to call it slush. 252 00:12:54,080 --> 00:12:56,660 They have a slush in here. 253 00:12:56,660 --> 00:13:01,660 The other terminology that people give this is, it's 254 00:13:01,660 --> 00:13:02,900 lens-shaped, right? 255 00:13:02,900 --> 00:13:04,100 Looks like a lens. 256 00:13:04,100 --> 00:13:06,150 So let's call this lens shape. 257 00:13:06,150 --> 00:13:07,570 So we're going to use the Latin word for 258 00:13:07,570 --> 00:13:09,760 lens, which is lens. 259 00:13:09,760 --> 00:13:11,670 But we want to make it adjectival. 260 00:13:11,670 --> 00:13:13,820 So we're going to use the adjective-- 261 00:13:13,820 --> 00:13:17,020 what's the genetive form of lens? 262 00:13:17,020 --> 00:13:17,640 Lentis? 263 00:13:17,640 --> 00:13:20,360 So we will call this lenticular. 264 00:13:20,360 --> 00:13:21,740 This is lenticular. 265 00:13:21,740 --> 00:13:25,280 The phase diagram has a lenticular shape. 266 00:13:25,280 --> 00:13:28,530 Looks like a lens. 267 00:13:28,530 --> 00:13:32,760 And you know, just as over here, I showed you, every line 268 00:13:32,760 --> 00:13:35,510 represents a coexistence curve, right? 269 00:13:35,510 --> 00:13:37,680 The lines are all coexistence curves. 270 00:13:37,680 --> 00:13:39,830 These lines are coexistence curves. 271 00:13:39,830 --> 00:13:43,740 The line up here is liquid equals vapor, so this one must 272 00:13:43,740 --> 00:13:46,570 be the coexistence of the two things on either side. 273 00:13:46,570 --> 00:13:47,530 So what do I have here? 274 00:13:47,530 --> 00:13:48,330 I have liquid. 275 00:13:48,330 --> 00:13:49,650 Here I have slush. 276 00:13:49,650 --> 00:13:50,750 So I'm going to write that. 277 00:13:50,750 --> 00:13:54,240 So I'm going to write the equilibrium, liquid goes to 278 00:13:54,240 --> 00:13:55,890 liquid plus solid. 279 00:13:55,890 --> 00:13:58,810 And this line, this coexistence curve, it's called 280 00:13:58,810 --> 00:14:01,650 the liquidus line. 281 00:14:06,950 --> 00:14:11,730 This is the liquidus equilibrium, the liquidus 282 00:14:11,730 --> 00:14:13,690 coexistence curve, and so on. 283 00:14:13,690 --> 00:14:14,800 And so what's the liquidus? 284 00:14:14,800 --> 00:14:16,800 The liquidus is the lowest temperature. 285 00:14:16,800 --> 00:14:18,370 So you pick a composition. 286 00:14:18,370 --> 00:14:21,200 The liquidus is the lowest temperature at which you can 287 00:14:21,200 --> 00:14:24,490 have a single-phase liquid solution, OK? 288 00:14:24,490 --> 00:14:26,730 So liquidus equilibrium. 289 00:14:26,730 --> 00:14:39,610 And the liquidus is the lowest temperature at which all 290 00:14:39,610 --> 00:14:43,185 liquid is stable. 291 00:14:43,185 --> 00:14:45,830 You go below that temperature at that composition, you start 292 00:14:45,830 --> 00:14:48,630 making solid, because slush requires that there be some 293 00:14:48,630 --> 00:14:50,190 solid present. 294 00:14:50,190 --> 00:14:53,960 And then the lower line, it also is a coexistence curve. 295 00:14:53,960 --> 00:14:55,400 So on the one side, I've got solid. 296 00:14:55,400 --> 00:14:57,300 On the other side, I've got slush. 297 00:14:57,300 --> 00:14:58,570 So I'm going to write that one down. 298 00:14:58,570 --> 00:15:02,790 That solid goes to liquid plus solid. 299 00:15:02,790 --> 00:15:07,850 And that's called the solidus equilibrium, or that's the 300 00:15:07,850 --> 00:15:10,830 solidus line, the solidus coexistence curve, and the 301 00:15:10,830 --> 00:15:11,790 solidus is the complement. 302 00:15:11,790 --> 00:15:14,920 The solidus is the highest temperature at which you can 303 00:15:14,920 --> 00:15:15,945 have all solid present. 304 00:15:15,945 --> 00:15:19,340 So you pick a composition, and I'll tell you what the highest 305 00:15:19,340 --> 00:15:21,270 temperature is at which you'll have a 306 00:15:21,270 --> 00:15:23,100 single-phase solid solution. 307 00:15:23,100 --> 00:15:33,820 So solidus is the highest temperature at which 308 00:15:33,820 --> 00:15:39,310 all solid is stable. 309 00:15:39,310 --> 00:15:40,930 All right. 310 00:15:40,930 --> 00:15:41,210 Good. 311 00:15:41,210 --> 00:15:43,320 And I'm going to look at a few of these things. 312 00:15:43,320 --> 00:15:46,550 It's always fun to see if I'm on track with the 313 00:15:46,550 --> 00:15:47,330 Hume-Rothery rule. 314 00:15:47,330 --> 00:15:50,650 So here's copper nickel. 315 00:15:50,650 --> 00:15:52,420 They're both FCC metals. 316 00:15:52,420 --> 00:15:55,990 So we've got copper melting at about 1085, nickel melting at 317 00:15:55,990 --> 00:15:57,220 about 1455. 318 00:15:57,220 --> 00:16:01,020 And there's the phase diagram, lenticular phase diagram. 319 00:16:01,020 --> 00:16:03,530 So up here is all liquid, and then-- 320 00:16:03,530 --> 00:16:05,490 this is all metallurgy terminology. 321 00:16:05,490 --> 00:16:11,740 A solid solution of A and B, they call alpha. 322 00:16:11,740 --> 00:16:13,690 Metallurgist looks at that, goes oh, it must be a solid 323 00:16:13,690 --> 00:16:15,130 solution, OK? 324 00:16:15,130 --> 00:16:17,230 So there's p equals 2 in between, 325 00:16:17,230 --> 00:16:19,740 p equals 1, p equals-- 326 00:16:19,740 --> 00:16:21,330 Here's a ceramic system. 327 00:16:21,330 --> 00:16:24,030 This is nickel oxide, magnesium oxide. 328 00:16:24,030 --> 00:16:26,890 It's not metals, but they have identical crystal structures, 329 00:16:26,890 --> 00:16:28,800 very similar atomic volumes. 330 00:16:28,800 --> 00:16:31,990 They're ions, so we have nickel and magnesium 331 00:16:31,990 --> 00:16:35,440 substituting for one another on the cationic sublattice. 332 00:16:35,440 --> 00:16:38,750 So they must have very nearly equal sizes. 333 00:16:38,750 --> 00:16:42,010 If I look at this, and I see a lenticular diagram, it means 334 00:16:42,010 --> 00:16:44,080 they must have similar atomic volumes, which means the 335 00:16:44,080 --> 00:16:47,230 dominant defect in here must be Schottky, not Frankel 336 00:16:47,230 --> 00:16:50,380 because Frankel needs a big difference in atomic volume. 337 00:16:50,380 --> 00:16:52,520 If you have a big difference in atomic volume, we wouldn't 338 00:16:52,520 --> 00:16:54,410 have a lenticular phase diagram. 339 00:16:54,410 --> 00:16:57,530 So here's-- mag oxide melts at 2800 degrees centigrade. 340 00:16:57,530 --> 00:16:58,430 It's a great refractory. 341 00:16:58,430 --> 00:17:00,220 You can hold molten iron in it. 342 00:17:00,220 --> 00:17:02,670 And here's nickel oxide down here. 343 00:17:02,670 --> 00:17:02,870 All right. 344 00:17:02,870 --> 00:17:03,770 Here's an interesting one. 345 00:17:03,770 --> 00:17:04,670 This is gold nickel. 346 00:17:04,670 --> 00:17:06,220 Both FCC metals. 347 00:17:06,220 --> 00:17:09,020 Shade your eyes from the lower part. 348 00:17:09,020 --> 00:17:10,420 Just look at the upper part. 349 00:17:10,420 --> 00:17:11,670 It looks lenticular. 350 00:17:13,750 --> 00:17:15,310 It's what you'd expect, gold and nickel. 351 00:17:15,310 --> 00:17:17,980 They're both, you know, card-bearing metals. 352 00:17:17,980 --> 00:17:21,940 But you've seen already, with the cesium-gold, gold has a 353 00:17:21,940 --> 00:17:25,040 fairly high electronegativity. 354 00:17:25,040 --> 00:17:28,640 And what happens is that you get over here, at about 33 355 00:17:28,640 --> 00:17:35,320 atomic percent of nickel in gold, you have an atomic ratio 356 00:17:35,320 --> 00:17:38,310 that allows to have something that starting to approximate 357 00:17:38,310 --> 00:17:39,250 electron transfer. 358 00:17:39,250 --> 00:17:41,640 So it's almost as though you have a lenticular phase 359 00:17:41,640 --> 00:17:46,880 diagram between pure nickel and this nickel-gold compound. 360 00:17:46,880 --> 00:17:49,750 But up in here, it's nice lenticular stuff. 361 00:17:49,750 --> 00:17:50,400 All right. 362 00:17:50,400 --> 00:17:51,970 What's the next one? 363 00:17:51,970 --> 00:17:52,300 Oh, yeah. 364 00:17:52,300 --> 00:17:54,690 So now I want to go in and I want to start talking about 365 00:17:54,690 --> 00:17:56,270 what goes on inside here. 366 00:17:56,270 --> 00:17:59,780 So what I'm going to do, is I'm going to blow this up. 367 00:17:59,780 --> 00:18:04,000 And I'm going to start at 40%, 40 weight percent nickel, and 368 00:18:04,000 --> 00:18:07,100 I'm going to say, what happens if we take a crucible that's 369 00:18:07,100 --> 00:18:11,330 40 weight percent nickel and copper, and we cool it from 370 00:18:11,330 --> 00:18:16,810 all liquid at 1300, down to all solid at 1200, pausing in 371 00:18:16,810 --> 00:18:18,800 that slush zone at 1250? 372 00:18:18,800 --> 00:18:21,000 So we're going to take snapshots and say, what's the 373 00:18:21,000 --> 00:18:24,870 contents of the crucible look like at 1300, at 1250, and at 374 00:18:24,870 --> 00:18:29,030 1200, and come out of it, have an appreciation for what all 375 00:18:29,030 --> 00:18:30,570 of this stuff means. 376 00:18:30,570 --> 00:18:33,590 So let's start our experiment. 377 00:18:33,590 --> 00:18:36,400 So we're going to have three crucibles here. 378 00:18:36,400 --> 00:18:48,560 And we're going to start with 40% nickel in copper, and 379 00:18:48,560 --> 00:18:52,880 that's going to be the experiment we'll perform. 380 00:18:52,880 --> 00:18:55,990 So I've got three crucibles. 381 00:18:55,990 --> 00:19:00,830 And so if I look at the phase diagram, here I am. 382 00:19:00,830 --> 00:19:07,690 This was 1300 degrees C, this was at 1250 degrees C, and 383 00:19:07,690 --> 00:19:10,990 then this was at 1200 degrees C. 384 00:19:10,990 --> 00:19:13,450 So at 1300, that's trivial. 385 00:19:13,450 --> 00:19:17,170 1300 for this thing, it should be just all liquid. 386 00:19:17,170 --> 00:19:18,780 And maybe it's copper. 387 00:19:18,780 --> 00:19:21,590 I know at this temperature, it's going to be blinding 388 00:19:21,590 --> 00:19:22,560 white heat. 389 00:19:22,560 --> 00:19:23,310 So it doesn't matter. 390 00:19:23,310 --> 00:19:24,000 I could use this. 391 00:19:24,000 --> 00:19:26,252 But I felt compelled, it's one of those rare opportunities to 392 00:19:26,252 --> 00:19:27,140 use colored chalk. 393 00:19:27,140 --> 00:19:29,730 So I want this to sort of be copper-colored. 394 00:19:29,730 --> 00:19:31,940 The meniscus is going to look like this, because the liquid 395 00:19:31,940 --> 00:19:33,680 metals have a very high surface tension. 396 00:19:33,680 --> 00:19:34,910 They want to ball up. 397 00:19:34,910 --> 00:19:36,850 So you're going to have a meniscus looking like this, 398 00:19:36,850 --> 00:19:43,100 and this is all single phase, all liquid. 399 00:19:43,100 --> 00:19:45,640 And over here, I'm going to do the easy one. 400 00:19:45,640 --> 00:19:48,440 If we get down to 1200, it's all solid state, right? 401 00:19:48,440 --> 00:19:51,220 At 1200, I'm going to end up with something that's solid, 402 00:19:51,220 --> 00:19:57,040 and it's going to be polycrystalline, and these are 403 00:19:57,040 --> 00:19:59,180 all going to be grains of alpha. 404 00:19:59,180 --> 00:20:02,220 All solid. 405 00:20:02,220 --> 00:20:05,500 And I'm going to label all of these as alpha solid solution. 406 00:20:05,500 --> 00:20:09,600 They all have the same composition, which is 40% 407 00:20:09,600 --> 00:20:11,830 nickel in copper. 408 00:20:15,490 --> 00:20:18,850 And these are all 40% nickel. 409 00:20:18,850 --> 00:20:21,930 Now, according to this phase diagram, when we get down into 410 00:20:21,930 --> 00:20:24,530 the center there, something else happens. 411 00:20:24,530 --> 00:20:27,150 We end up in a two-phase regime. 412 00:20:27,150 --> 00:20:30,740 And that two-phase regime is a regime in which certain 413 00:20:30,740 --> 00:20:34,490 compositions are forbidden because that's an equilibrium. 414 00:20:34,490 --> 00:20:37,440 It doesn't allow us to have what's in between. 415 00:20:37,440 --> 00:20:41,840 I think the next slide actually shows this. 416 00:20:41,840 --> 00:20:49,800 So what I've designated as c2 is this 40%. 417 00:20:49,800 --> 00:20:54,260 So c2 is now going to park at that point in the middle. 418 00:20:54,260 --> 00:20:54,850 Whoops! 419 00:20:54,850 --> 00:20:56,730 Want to get into that. 420 00:20:56,730 --> 00:20:58,080 So here's where we are. 421 00:20:58,080 --> 00:21:00,950 We're in the center of that two-phase regime. 422 00:21:00,950 --> 00:21:02,200 So this is the solidus. 423 00:21:04,520 --> 00:21:05,770 This is the liquidus. 424 00:21:08,850 --> 00:21:10,940 And we're at 1250. 425 00:21:10,940 --> 00:21:12,190 t equals-- 426 00:21:15,040 --> 00:21:16,740 And we're at this value. 427 00:21:16,740 --> 00:21:19,580 We started at c2, which is 40%. 428 00:21:19,580 --> 00:21:24,370 But in this regime, 40% is forbidden. 429 00:21:24,370 --> 00:21:28,660 If you stop at 40% at 1250, this says that the stable 430 00:21:28,660 --> 00:21:31,820 phases are a liquid and a solid. 431 00:21:31,820 --> 00:21:35,460 But the liquid has less nickel in it, and the solid has more 432 00:21:35,460 --> 00:21:36,530 nickel in it. 433 00:21:36,530 --> 00:21:38,230 It's like if this is a solubility limit. 434 00:21:38,230 --> 00:21:41,290 In other words, if you started at pure copper, and you 435 00:21:41,290 --> 00:21:43,560 started adding nickel, you can keep adding nickel until you 436 00:21:43,560 --> 00:21:45,150 get to this concentration. 437 00:21:45,150 --> 00:21:47,000 You try to add any more nickel, it's like adding too 438 00:21:47,000 --> 00:21:48,130 much sugar to water. 439 00:21:48,130 --> 00:21:49,310 What do you have? 440 00:21:49,310 --> 00:21:51,100 The stuff just falls to the bottom of the 441 00:21:51,100 --> 00:21:52,730 cup, doesn't dissolve. 442 00:21:52,730 --> 00:21:53,690 That's this. 443 00:21:53,690 --> 00:21:54,530 It's the solid. 444 00:21:54,530 --> 00:21:57,710 Only instead of being pure nickel, it's still a copper 445 00:21:57,710 --> 00:21:59,600 nickel solution, but kind of rich. 446 00:21:59,600 --> 00:22:01,710 So I'm going to call this c star. 447 00:22:01,710 --> 00:22:05,240 It's the solubility limit on the liquid side. 448 00:22:05,240 --> 00:22:08,650 And this one here I'm going to call c star on the solid side. 449 00:22:08,650 --> 00:22:11,130 In other words, I could start from this side, and keep 450 00:22:11,130 --> 00:22:14,520 adding copper to nickel, and I make a homogeneous alloy until 451 00:22:14,520 --> 00:22:15,910 I get to this composition. 452 00:22:15,910 --> 00:22:19,080 If I try to add any more copper, I jump across. 453 00:22:19,080 --> 00:22:20,900 So we're here in the middle. 454 00:22:20,900 --> 00:22:23,050 But now, isn't there something strange here? 455 00:22:23,050 --> 00:22:27,450 It's saying I'm going to have a liquid that's nickel-poor 456 00:22:27,450 --> 00:22:29,100 and a solid that's nickel-rich. 457 00:22:29,100 --> 00:22:32,230 And I'm just putting up here what the diagram says. 458 00:22:32,230 --> 00:22:35,310 And we know that FCC metals, which is denser, the 459 00:22:35,310 --> 00:22:37,610 liquid or the solid? 460 00:22:37,610 --> 00:22:38,200 The solid. 461 00:22:38,200 --> 00:22:43,430 So down here I'm going to have alpha, OK, a bunch of grains 462 00:22:43,430 --> 00:22:47,850 of alpha solid solution, and up here, I'm going to have a 463 00:22:47,850 --> 00:22:49,700 liquid solution. 464 00:22:49,700 --> 00:22:53,310 And the composition here is c star liquid, and the 465 00:22:53,310 --> 00:22:56,150 composition here is c star solid. 466 00:22:56,150 --> 00:22:57,900 It's different composition from this. 467 00:22:57,900 --> 00:23:02,270 Here the composition is equal to c2, or the 40% nickel. 468 00:23:02,270 --> 00:23:04,640 So I've got disproportionation. 469 00:23:04,640 --> 00:23:08,610 But the total mass, I can't have sources or sinks. 470 00:23:08,610 --> 00:23:10,010 So I have to conserve mass. 471 00:23:10,010 --> 00:23:12,820 So I'm going to ask you to just do the algebra. 472 00:23:12,820 --> 00:23:14,760 You've got two equations and two unknowns. 473 00:23:14,760 --> 00:23:17,730 I know what the n-member concentrations are. 474 00:23:17,730 --> 00:23:19,930 They're given by the n's of this thing 475 00:23:19,930 --> 00:23:21,780 called the tie line. 476 00:23:21,780 --> 00:23:25,170 The tie line ties the two ends of the two-phase region 477 00:23:25,170 --> 00:23:27,830 together, and then we just do a mass balance. 478 00:23:27,830 --> 00:23:29,590 Well, fortunately, the metallurgists have thought 479 00:23:29,590 --> 00:23:31,890 about this for a while, so we don't have to go through and 480 00:23:31,890 --> 00:23:35,210 figure out, well, if two apples cost 15 cents-- 481 00:23:35,210 --> 00:23:36,780 we don't have to do that kind of thing. 482 00:23:36,780 --> 00:23:42,580 We can just invoke the lever rule, and it will tell us how 483 00:23:42,580 --> 00:23:46,610 much of the liquid that's nickel-depleted and solid 484 00:23:46,610 --> 00:23:49,060 that's nickel-rich add up to this. 485 00:23:49,060 --> 00:23:52,320 And so let's look at the lever rule. 486 00:23:52,320 --> 00:23:55,320 Basically what's going to happen here is that the stuff 487 00:23:55,320 --> 00:24:04,870 that started off as 40% nickel, 60% copper, that's my 488 00:24:04,870 --> 00:24:10,700 initial mix, it's going to break into two layers. 489 00:24:10,700 --> 00:24:13,560 It's going to break into a liquid layer, which, if you go 490 00:24:13,560 --> 00:24:17,230 to the phase diagram, looks like it's about 38% nickel and 491 00:24:17,230 --> 00:24:20,255 68% copper, and that's what we're going 492 00:24:20,255 --> 00:24:22,890 to call c star liquid. 493 00:24:22,890 --> 00:24:32,030 And then over here it's 45% percent nickel and 55% copper. 494 00:24:32,030 --> 00:24:36,200 And that's what we call c star of the solid. 495 00:24:36,200 --> 00:24:37,890 And so it's just a lever. 496 00:24:37,890 --> 00:24:39,100 So there's c star. 497 00:24:39,100 --> 00:24:41,500 This is the c2 that we want. 498 00:24:41,500 --> 00:24:44,600 And we want to ask, what's the relative amount of the liquid 499 00:24:44,600 --> 00:24:46,630 phase and the solid phase? 500 00:24:46,630 --> 00:24:49,460 And why they call it a lever rule is, look, if you cooled 501 00:24:49,460 --> 00:24:51,170 something that was at this composition, it 502 00:24:51,170 --> 00:24:53,190 would be 100% liquid. 503 00:24:53,190 --> 00:24:55,530 And if you cooled something at this composition, it will be 504 00:24:55,530 --> 00:24:56,700 100% solid. 505 00:24:56,700 --> 00:24:58,530 And so it's going to be a constant 506 00:24:58,530 --> 00:25:00,420 variation across here. 507 00:25:00,420 --> 00:25:02,920 So you use, you take this, and you know, and I want this 508 00:25:02,920 --> 00:25:06,260 amount, I'm taking this versus this, kind of thing. 509 00:25:06,260 --> 00:25:08,460 It's a lever construction. 510 00:25:08,460 --> 00:25:09,510 So we'll just put it down. 511 00:25:09,510 --> 00:25:21,400 So the percent of the liquid in the crucible at 1250-- 512 00:25:21,400 --> 00:25:22,920 and then this is a general thing. 513 00:25:22,920 --> 00:25:26,180 Whenever p equals 2, you'll use a lever rule. 514 00:25:26,180 --> 00:25:30,590 Percent of the liquid is given by this one. 515 00:25:30,590 --> 00:25:33,760 The composition of the solid at the end of the tie line 516 00:25:33,760 --> 00:25:36,030 minus the composition that you started at. 517 00:25:36,030 --> 00:25:41,240 This is your bulk initial concentration, divided by the 518 00:25:41,240 --> 00:25:43,460 length of that tie line. 519 00:25:43,460 --> 00:25:48,200 c star solid minus c star liquid. 520 00:25:48,200 --> 00:25:50,990 And then multiplied by 100%. 521 00:25:50,990 --> 00:25:54,850 So you get a percent, and the number here is going to be 45 522 00:25:54,850 --> 00:26:01,850 minus 40 over 45 minus 32, and that works out-- 523 00:26:01,850 --> 00:26:06,530 going to multiply by 100, or else there will be complaints. 524 00:26:06,530 --> 00:26:09,290 And then this turns out to be 38%. 525 00:26:09,290 --> 00:26:11,890 So what that means is that if you take this 526 00:26:11,890 --> 00:26:15,320 amount of liquid here-- 527 00:26:15,320 --> 00:26:18,320 pardon me-- based on conservation of mass, if you 528 00:26:18,320 --> 00:26:28,790 drop and hold at 1250, 38% of that volume is now sitting 529 00:26:28,790 --> 00:26:35,470 here in the liquid, which means 62% of it by volume has 530 00:26:35,470 --> 00:26:36,940 turned into solid. 531 00:26:36,940 --> 00:26:39,620 And the composition here is different from the composition 532 00:26:39,620 --> 00:26:44,380 here, but if you add up all the nickel in the crucible and 533 00:26:44,380 --> 00:26:48,180 sum it versus all the copper in the crucible, you still end 534 00:26:48,180 --> 00:26:49,855 up with 40% net nickel. 535 00:26:49,855 --> 00:26:52,740 So this very powerful. 536 00:26:52,740 --> 00:26:55,600 Because what you can do here is you can separate metal. 537 00:26:55,600 --> 00:27:00,150 Because I started here with 40% nickel, 60% copper, and 538 00:27:00,150 --> 00:27:02,360 now I've got something-- 539 00:27:02,360 --> 00:27:06,880 the liquid face, I wrote here, the liquid 540 00:27:06,880 --> 00:27:10,090 phase is now 68% copper. 541 00:27:10,090 --> 00:27:12,940 So can you see that if I'm clever about this, I could use 542 00:27:12,940 --> 00:27:16,730 this as a technique for enriching. 543 00:27:16,730 --> 00:27:19,790 And if I'm thinking about recycling metals, maybe I need 544 00:27:19,790 --> 00:27:22,760 to know something about phase diagrams because it's a very 545 00:27:22,760 --> 00:27:26,320 simple way of concentrating impurities or concentrating 546 00:27:26,320 --> 00:27:28,390 the desirable stuff. 547 00:27:28,390 --> 00:27:31,410 Let's look at one other thing here that's really very 548 00:27:31,410 --> 00:27:32,550 interesting. 549 00:27:32,550 --> 00:27:37,250 Suppose I had something, instead of c2 at 40%, suppose 550 00:27:37,250 --> 00:27:38,800 I choose a c1. 551 00:27:38,800 --> 00:27:41,360 So this is 40% nickel. 552 00:27:41,360 --> 00:27:46,220 Now what if I take something that's 35% nickel, and I cool 553 00:27:46,220 --> 00:27:48,390 it down to 1250? 554 00:27:48,390 --> 00:27:49,570 What happens? 555 00:27:49,570 --> 00:27:52,460 If I park here at 1250 degrees, according to the 556 00:27:52,460 --> 00:27:57,280 phase diagram, that substance has to phase separate, and I'm 557 00:27:57,280 --> 00:27:59,000 going to end up with the same thing. 558 00:27:59,000 --> 00:28:01,310 I'm going to end up with liquid and solid. 559 00:28:01,310 --> 00:28:03,380 Now, isn't there a contradiction there? 560 00:28:03,380 --> 00:28:07,420 How is it that whether I started with 40% or 35%, I end 561 00:28:07,420 --> 00:28:09,450 up with the same end members? 562 00:28:09,450 --> 00:28:11,630 What's the missing piece? 563 00:28:11,630 --> 00:28:14,250 The relative amounts will be different! 564 00:28:14,250 --> 00:28:15,360 The relative amounts. 565 00:28:15,360 --> 00:28:16,470 Here, look. 566 00:28:16,470 --> 00:28:18,960 As I'm getting closer to the liquid, can you see that 567 00:28:18,960 --> 00:28:21,540 axiomatically, I'm going to make more liquid and less 568 00:28:21,540 --> 00:28:24,320 solid if I ended up with something over here? 569 00:28:24,320 --> 00:28:26,610 But at 1250, those are the end members. 570 00:28:26,610 --> 00:28:29,060 That's the only stuff that's going to be present. 571 00:28:29,060 --> 00:28:29,970 Ah! 572 00:28:29,970 --> 00:28:30,610 That's so good. 573 00:28:30,610 --> 00:28:33,020 I think I've got some other stuff here. 574 00:28:33,020 --> 00:28:33,320 Oh yeah. 575 00:28:33,320 --> 00:28:34,140 Oh, this was-- yeah. 576 00:28:34,140 --> 00:28:36,010 So p equals 2. 577 00:28:36,010 --> 00:28:37,110 Lever rule. 578 00:28:37,110 --> 00:28:42,340 Whenever you see p equals 2, you have two things you think 579 00:28:42,340 --> 00:28:44,390 of. p equals 2 means phase separation. 580 00:28:47,980 --> 00:28:50,530 And that phase separation means you're going to get 581 00:28:50,530 --> 00:28:52,410 different amounts, and the lever rule. 582 00:28:52,410 --> 00:28:54,950 And why I have this Manchurian Candidate-- 583 00:28:54,950 --> 00:28:55,760 it's this movie. 584 00:28:55,760 --> 00:28:56,610 I know there's a remake. 585 00:28:56,610 --> 00:28:58,450 The remake is horrible. 586 00:28:58,450 --> 00:29:01,360 The original, if you see the original, is about some 587 00:29:01,360 --> 00:29:02,185 fellows that were brainwashed. 588 00:29:02,185 --> 00:29:04,890 They were American prisoners of war brainwashed in North 589 00:29:04,890 --> 00:29:08,210 Korea and they're brainwashed to become assassins on cue. 590 00:29:08,210 --> 00:29:10,760 And the cue is the Queen of Diamonds. 591 00:29:10,760 --> 00:29:13,110 When someone shows the Queen of Diamonds, they just go into 592 00:29:13,110 --> 00:29:15,780 automatic pilot, and they're supposed to assassinate the 593 00:29:15,780 --> 00:29:16,910 political figure. 594 00:29:16,910 --> 00:29:21,020 So for you, your Queen of Diamonds is p equals 2. 595 00:29:21,020 --> 00:29:24,230 When you see p equals 2, you go, phase separation. 596 00:29:24,230 --> 00:29:25,285 Lever rule. 597 00:29:25,285 --> 00:29:26,060 All right? 598 00:29:26,060 --> 00:29:27,500 No guns, just this. 599 00:29:27,500 --> 00:29:29,160 I just want the formula. 600 00:29:29,160 --> 00:29:32,360 You go, phase separation, lever rule. 601 00:29:32,360 --> 00:29:36,370 Whenever p equals two. 602 00:29:36,370 --> 00:29:38,740 So what happens in here? 603 00:29:38,740 --> 00:29:39,800 Phase separation. 604 00:29:39,800 --> 00:29:40,390 Boom, boom. 605 00:29:40,390 --> 00:29:40,930 Right there. 606 00:29:40,930 --> 00:29:42,350 Oh, I'm not supposed to say boom, boom. 607 00:29:42,350 --> 00:29:43,810 Phase separation. 608 00:29:43,810 --> 00:29:44,430 Ta-da! 609 00:29:44,430 --> 00:29:45,420 You know, something. 610 00:29:45,420 --> 00:29:47,080 PC, whatever. 611 00:29:47,080 --> 00:29:47,390 OK. 612 00:29:47,390 --> 00:29:48,960 So let's keep going. 613 00:29:48,960 --> 00:29:52,320 Now I want to look at a second type of phase diagram. 614 00:29:52,320 --> 00:29:54,630 So the first type of phase diagram was complete 615 00:29:54,630 --> 00:29:55,870 solubility. 616 00:29:55,870 --> 00:29:58,730 Now the second type of phase diagram has partial 617 00:29:58,730 --> 00:29:59,390 solubility. 618 00:29:59,390 --> 00:30:01,870 So let's look at that one. 619 00:30:01,870 --> 00:30:03,280 So i call this type two. 620 00:30:05,830 --> 00:30:06,970 And you don't predict this stuff. 621 00:30:06,970 --> 00:30:10,270 We would give you the phase diagram and simply ask you, 622 00:30:10,270 --> 00:30:13,860 you know, you're the specialist. Tell me happens if 623 00:30:13,860 --> 00:30:16,250 I cool this to such and such a temperature? 624 00:30:16,250 --> 00:30:18,390 You can tell me you get phase separation, and the 625 00:30:18,390 --> 00:30:20,470 composition of the two end members, and so on. 626 00:30:20,470 --> 00:30:23,110 So the characteristics, the bonding characteristics here, 627 00:30:23,110 --> 00:30:35,880 are partial or limited solubility of A and B. 628 00:30:35,880 --> 00:30:39,700 We're doing all of this for a binary system A and B, and no 629 00:30:39,700 --> 00:30:40,950 change of state. 630 00:30:44,830 --> 00:30:52,920 So that means either always solid, or always liquid. 631 00:30:52,920 --> 00:30:55,800 That's not to say that the A and B never become solid. 632 00:30:55,800 --> 00:30:58,960 I'm just saying that a type two diagram is limited to a 633 00:30:58,960 --> 00:31:03,160 single state. 634 00:31:03,160 --> 00:31:05,590 So let's take a look at the diagram. 635 00:31:05,590 --> 00:31:07,380 The diagram looks like this. 636 00:31:07,380 --> 00:31:10,100 We're going to plot temperature versus 637 00:31:10,100 --> 00:31:10,860 composition. 638 00:31:10,860 --> 00:31:14,150 So pure B on the right, pure A on the left. 639 00:31:14,150 --> 00:31:18,810 Concentration is the abscissa, and then the ordinate, of 640 00:31:18,810 --> 00:31:20,890 course, is temperature. 641 00:31:20,890 --> 00:31:24,690 And so the shape of the diagram is this. 642 00:31:24,690 --> 00:31:27,360 There's the coexistence curve. 643 00:31:27,360 --> 00:31:32,895 It's called a synclinal coexistence curve. 644 00:31:38,510 --> 00:31:44,740 So above, we have all solid. 645 00:31:44,740 --> 00:31:47,430 And in here, we have two solids. 646 00:31:47,430 --> 00:31:49,990 So using the metallurgical terms, this 647 00:31:49,990 --> 00:31:51,600 is alpha plus beta. 648 00:31:51,600 --> 00:31:53,570 Two phase regime, OK? 649 00:31:53,570 --> 00:31:56,910 So let's get those labels up right off the bat, so we know 650 00:31:56,910 --> 00:31:57,560 who's where. 651 00:31:57,560 --> 00:32:02,620 So outside the coexistence curve, p equals 1. 652 00:32:02,620 --> 00:32:05,830 Inside the coexistence curve, p equals 2. 653 00:32:05,830 --> 00:32:08,440 And wherever I'm saying all solid, alpha plus beta, I 654 00:32:08,440 --> 00:32:11,700 could write all liquid, and then it goes to l1 plus l2. 655 00:32:11,700 --> 00:32:15,780 So maybe we should do that, to show that we're multilingual. 656 00:32:15,780 --> 00:32:22,680 So it's either all solid, or it could be all liquid. 657 00:32:22,680 --> 00:32:25,080 And then this would be liquid 1 plus liquid 2. 658 00:32:28,070 --> 00:32:31,400 And so why do we call it synclinal? 659 00:32:31,400 --> 00:32:32,570 What's this? 660 00:32:32,570 --> 00:32:34,320 This is an incline. 661 00:32:34,320 --> 00:32:35,970 If I put two inclines and I synchronize 662 00:32:35,970 --> 00:32:37,780 them, I get a syncline. 663 00:32:37,780 --> 00:32:39,300 And if I don't synchronize them-- 664 00:32:39,300 --> 00:32:40,060 these are two ladders. 665 00:32:40,060 --> 00:32:40,910 I could prop them up. 666 00:32:40,910 --> 00:32:42,900 That's called a syncline. 667 00:32:42,900 --> 00:32:45,745 And if I put two ladders like this, if I'm really stupid and 668 00:32:45,745 --> 00:32:48,410 I fail physics, if I do this, they fall down. 669 00:32:48,410 --> 00:32:51,220 So this is called an anticline, OK? 670 00:32:51,220 --> 00:32:52,100 That's an anticline. 671 00:32:52,100 --> 00:32:53,350 This is a syncline. 672 00:32:57,380 --> 00:33:01,700 It's not a U-shape, or a hump, or something like that. 673 00:33:01,700 --> 00:33:02,620 This is 3091. 674 00:33:02,620 --> 00:33:03,740 This is a syncline. 675 00:33:03,740 --> 00:33:05,230 Synclinal coexistence curve. 676 00:33:05,230 --> 00:33:05,520 All right. 677 00:33:05,520 --> 00:33:06,620 So what's on here? 678 00:33:06,620 --> 00:33:08,960 What's this equilibrium, then? 679 00:33:08,960 --> 00:33:11,630 Well, the equilibrium must be this equals this. 680 00:33:11,630 --> 00:33:14,560 So that would be, in the case of the solid, it's the solid 681 00:33:14,560 --> 00:33:19,100 solution goes to alpha plus beta, or it could be the 682 00:33:19,100 --> 00:33:23,570 liquid goes to liquid 1 plus liquid 2. 683 00:33:23,570 --> 00:33:26,110 That's the equilibrium. 684 00:33:26,110 --> 00:33:28,550 You can think about it almost as a solubility. 685 00:33:28,550 --> 00:33:30,140 So let's start over here on the left. 686 00:33:30,140 --> 00:33:31,190 Let's pick a temperature. 687 00:33:31,190 --> 00:33:32,670 Let's call this T1. 688 00:33:32,670 --> 00:33:37,270 So I can put B into A, and I continue to get an all-solid 689 00:33:37,270 --> 00:33:40,060 solution, up to this concentration here. 690 00:33:40,060 --> 00:33:42,230 What happens at this concentration? 691 00:33:42,230 --> 00:33:44,050 I've hit a solubility limit. 692 00:33:44,050 --> 00:33:47,545 And if I try to put any more B into A, I get a tie line-- 693 00:33:50,220 --> 00:33:51,290 lever rule. 694 00:33:51,290 --> 00:33:54,210 In here is lever rule time, isn't it? 695 00:33:54,210 --> 00:33:56,780 Lever rule. p equals 2, OK? 696 00:33:56,780 --> 00:33:59,010 So it's solubility limits. 697 00:33:59,010 --> 00:34:00,260 Solubility limits. 698 00:34:02,550 --> 00:34:02,850 All right. 699 00:34:02,850 --> 00:34:06,820 So let's look at some examples. 700 00:34:06,820 --> 00:34:07,760 Oh, here's this one, actually. 701 00:34:07,760 --> 00:34:08,720 That's why I had a-- 702 00:34:08,720 --> 00:34:10,995 you know, if you go to lower temperature, gold, nickel-- 703 00:34:10,995 --> 00:34:12,520 look! 704 00:34:12,520 --> 00:34:14,250 They actually phase separate. 705 00:34:14,250 --> 00:34:15,060 That's shocking. 706 00:34:15,060 --> 00:34:18,120 I always find this one shocking, because you think 707 00:34:18,120 --> 00:34:20,610 gold, nickel, nice FCC metals, they should 708 00:34:20,610 --> 00:34:21,850 substitute for one another. 709 00:34:21,850 --> 00:34:22,435 Look what happens. 710 00:34:22,435 --> 00:34:25,760 If you start putting nickel into pure gold at 700 degrees, 711 00:34:25,760 --> 00:34:28,440 you get the 10 weight percent, you put any more in, boom. 712 00:34:28,440 --> 00:34:30,870 Right across here. 713 00:34:30,870 --> 00:34:32,840 So this is going to be two phase. 714 00:34:32,840 --> 00:34:35,870 So if you look at the solid, what's that 715 00:34:35,870 --> 00:34:37,650 going to look like? 716 00:34:37,650 --> 00:34:41,400 If I'm at, say, 30%, now I look underneath and I've got a 717 00:34:41,400 --> 00:34:44,030 polygrain system, and I'm going to have an alpha and a 718 00:34:44,030 --> 00:34:47,160 beta, and an alpha and a beta. 719 00:34:47,160 --> 00:34:49,850 I'm going to have two different grains. 720 00:34:49,850 --> 00:34:52,000 And now, what's the relative amount of alpha and the 721 00:34:52,000 --> 00:34:53,340 relative amount of beta? 722 00:34:53,340 --> 00:34:55,860 It's given by the lever rule. 723 00:34:55,860 --> 00:34:56,970 OK. 724 00:34:56,970 --> 00:34:58,340 Let's look at a few other examples. 725 00:34:58,340 --> 00:35:01,130 Here's hexane nitrobenzene. 726 00:35:01,130 --> 00:35:04,190 And so they've even put l-alpha, l-beta. 727 00:35:04,190 --> 00:35:05,270 They put the-- 728 00:35:05,270 --> 00:35:06,630 actually, that's probably a-- 729 00:35:06,630 --> 00:35:07,350 it's hard to read. 730 00:35:07,350 --> 00:35:09,980 But I think it's really an F, but it didn't come through 731 00:35:09,980 --> 00:35:13,040 very well, so it's the beta fraction, the alpha fraction. 732 00:35:13,040 --> 00:35:14,930 So you can see how you use the lever rule. 733 00:35:14,930 --> 00:35:16,430 So up here it's all p. 734 00:35:16,430 --> 00:35:19,000 That's the not pressure, that's my circle p. 735 00:35:19,000 --> 00:35:20,550 Single phase, two phase. 736 00:35:20,550 --> 00:35:23,820 Drop down to 290 degrees, it separates into two liquids. 737 00:35:23,820 --> 00:35:24,930 With the hexane-- 738 00:35:24,930 --> 00:35:26,730 with two liquids, you'll actually have them floating on 739 00:35:26,730 --> 00:35:28,600 top of one another, right? 740 00:35:28,600 --> 00:35:29,310 Well, maybe. 741 00:35:29,310 --> 00:35:31,840 Depending if the density difference is tiny, you might 742 00:35:31,840 --> 00:35:32,710 get a dispersion. 743 00:35:32,710 --> 00:35:34,390 I'll show you that in a second. 744 00:35:34,390 --> 00:35:34,670 All right. 745 00:35:34,670 --> 00:35:36,680 So p equals 2, lever rule. 746 00:35:36,680 --> 00:35:38,740 OK? 747 00:35:38,740 --> 00:35:40,320 Hexane nitrobenzene. 748 00:35:40,320 --> 00:35:40,940 Look at this one. 749 00:35:40,940 --> 00:35:42,010 This is surprising to me. 750 00:35:42,010 --> 00:35:44,020 Potassium chloride, sodium chloride. 751 00:35:44,020 --> 00:35:46,420 It's almost lenticular with a little bit of depression, but 752 00:35:46,420 --> 00:35:47,670 down here, it actually separates. 753 00:35:50,660 --> 00:35:51,930 This is polymer. 754 00:35:51,930 --> 00:35:53,840 It's a polystyrene, polybutadiene, 755 00:35:53,840 --> 00:35:56,460 depending on what the-- 756 00:35:56,460 --> 00:36:01,150 at low index, polymerization index, they mix. 757 00:36:01,150 --> 00:36:03,360 At high polymerization index, the two are mixing. 758 00:36:03,360 --> 00:36:05,020 You get two phase, single phase. 759 00:36:05,020 --> 00:36:09,040 Changes the mechanical properties, too, doesn't it? 760 00:36:09,040 --> 00:36:10,220 Now this one-- 761 00:36:10,220 --> 00:36:13,720 some systems actually have a lower critical point. 762 00:36:13,720 --> 00:36:14,800 Oh, I meant to tell you. 763 00:36:14,800 --> 00:36:17,570 You see, there's this temperature here. 764 00:36:17,570 --> 00:36:20,290 Above this temperature, they mix in all proportions. 765 00:36:20,290 --> 00:36:22,400 You can ever have phase separation. 766 00:36:22,400 --> 00:36:25,560 This is the maximum temperature at which you have 767 00:36:25,560 --> 00:36:26,980 no phase separation. 768 00:36:26,980 --> 00:36:32,030 So this is called the consolute temperature. 769 00:36:32,030 --> 00:36:35,070 And it's usually an upper consolute. 770 00:36:35,070 --> 00:36:36,570 The higher you go in temperature-- 771 00:36:36,570 --> 00:36:39,320 it's like saying, do you dissolve more sugar in cold 772 00:36:39,320 --> 00:36:41,010 water or warm water? 773 00:36:41,010 --> 00:36:43,270 You dissolve more sugar in warm water. 774 00:36:43,270 --> 00:36:45,200 And eventually, you get to a temperature high enough that 775 00:36:45,200 --> 00:36:47,270 you can mix in all proportions, right? 776 00:36:47,270 --> 00:36:48,540 That's the consolute. 777 00:36:48,540 --> 00:36:50,970 Some systems, for entropic reasons-- and again, if you 778 00:36:50,970 --> 00:36:53,870 take 560 or some of the other thermal classes, you'll 779 00:36:53,870 --> 00:36:57,010 understand this, but for entropic reasons, you actually 780 00:36:57,010 --> 00:37:00,710 have homogeneous solutions at low temperature, and at 781 00:37:00,710 --> 00:37:02,640 elevated temperature, you get phase separation. 782 00:37:02,640 --> 00:37:03,840 That's funny, isn't it. 783 00:37:03,840 --> 00:37:06,860 So this is water triethylamine, and they mix in 784 00:37:06,860 --> 00:37:09,810 all proportions at this zone here. 785 00:37:09,810 --> 00:37:12,460 And then above a certain-- it's called lower consolute 786 00:37:12,460 --> 00:37:13,290 temperature. 787 00:37:13,290 --> 00:37:15,060 It actually phase separates. 788 00:37:15,060 --> 00:37:15,700 Doesn't matter. 789 00:37:15,700 --> 00:37:20,120 All you care about is p equals 2, phase 790 00:37:20,120 --> 00:37:22,410 separation, lever rule. 791 00:37:22,410 --> 00:37:24,110 The rest is details. 792 00:37:24,110 --> 00:37:25,700 This is a real hoot. 793 00:37:25,700 --> 00:37:27,320 This is water nicotine. 794 00:37:27,320 --> 00:37:30,460 It has a lower consolute temperature and an upper 795 00:37:30,460 --> 00:37:32,180 consolute temperature. 796 00:37:32,180 --> 00:37:34,015 So it's got a solubility bubble. 797 00:37:36,760 --> 00:37:37,760 You see? 798 00:37:37,760 --> 00:37:39,350 Out here, things are soluble. 799 00:37:39,350 --> 00:37:41,190 In here, they're insoluble. 800 00:37:41,190 --> 00:37:42,490 So they are emissible. 801 00:37:42,490 --> 00:37:46,270 So we call this zone, this region here under the dome, so 802 00:37:46,270 --> 00:37:55,160 to speak, this it's called the miscibility gap, because 803 00:37:55,160 --> 00:37:57,620 things in there are not soluble in one another. 804 00:37:57,620 --> 00:37:59,890 But with nicotine, you have a lower consolute and an upper 805 00:37:59,890 --> 00:38:01,740 consolute, so you have a miscibility gap that's a 806 00:38:01,740 --> 00:38:04,470 complete ring. 807 00:38:04,470 --> 00:38:05,615 That's cool! 808 00:38:05,615 --> 00:38:07,780 I like this. 809 00:38:07,780 --> 00:38:08,000 All right. 810 00:38:08,000 --> 00:38:09,240 So now I'm going to do a little experiment. 811 00:38:09,240 --> 00:38:10,990 We have a few minutes, so I'm going to show you ouzo water. 812 00:38:10,990 --> 00:38:14,830 I'm going to mix it, and I'm going to actually mix ouzo and 813 00:38:14,830 --> 00:38:18,420 water, and go into the two phase regime, and then out. 814 00:38:18,420 --> 00:38:20,050 So this is what it is, all right? 815 00:38:20,050 --> 00:38:21,510 It's oily stuff, you know. 816 00:38:21,510 --> 00:38:23,920 If you're of Greek ancestry, you know what this stuff is. 817 00:38:23,920 --> 00:38:24,290 All right? 818 00:38:24,290 --> 00:38:26,810 But it's got licorice, it's got a fair bit of oil in it. 819 00:38:26,810 --> 00:38:29,010 So what I'm going to do, is I'm going to come in here, and 820 00:38:29,010 --> 00:38:31,650 I'm going to start adding ouzo to water. 821 00:38:31,650 --> 00:38:34,400 And they're both clear, colorless liquids. 822 00:38:34,400 --> 00:38:35,765 OK, Dave. Let's go to the-- 823 00:38:39,854 --> 00:38:40,590 All right. 824 00:38:40,590 --> 00:38:44,520 So what we're going to do-- this is distilled water. 825 00:38:44,520 --> 00:38:46,490 So I'm going to put some distilled water in here. 826 00:38:46,490 --> 00:38:47,980 A little bit of distilled water. 827 00:38:47,980 --> 00:38:49,020 And this is ouzo. 828 00:38:49,020 --> 00:38:50,770 It's clear and colorless. 829 00:38:50,770 --> 00:38:51,020 OK. 830 00:38:51,020 --> 00:38:53,142 Can we show you this? 831 00:38:53,142 --> 00:38:54,470 Let's do this. 832 00:38:54,470 --> 00:38:54,770 OK. 833 00:38:54,770 --> 00:38:58,060 Ouzo, it comes from Greece. 834 00:38:58,060 --> 00:38:59,030 All right. 835 00:38:59,030 --> 00:39:01,780 So it's also clear and colorless. 836 00:39:01,780 --> 00:39:02,660 That was the point. 837 00:39:02,660 --> 00:39:03,840 Not to show you the label. 838 00:39:03,840 --> 00:39:04,100 See? 839 00:39:04,100 --> 00:39:05,590 It's clear and colorless. 840 00:39:05,590 --> 00:39:07,800 So this is clear and colorless, and the water, as 841 00:39:07,800 --> 00:39:09,340 you know, is clear and colorless. 842 00:39:09,340 --> 00:39:10,560 So now what I'm going to do-- 843 00:39:10,560 --> 00:39:11,995 see, I don't have to wear a smock, 844 00:39:11,995 --> 00:39:13,430 or goggles, or anything. 845 00:39:13,430 --> 00:39:14,590 This is great. 846 00:39:14,590 --> 00:39:15,760 So what I'm going to do, is I'm going to add 847 00:39:15,760 --> 00:39:16,570 some of this stuff. 848 00:39:16,570 --> 00:39:17,820 Clear and colorless. 849 00:39:21,690 --> 00:39:22,040 OK. 850 00:39:22,040 --> 00:39:22,910 It's turned milky. 851 00:39:22,910 --> 00:39:24,300 Why has it turned milky? 852 00:39:24,300 --> 00:39:29,070 Because we've now crossed into here, and the second phase is 853 00:39:29,070 --> 00:39:29,890 coming out. 854 00:39:29,890 --> 00:39:32,830 But the density difference and surface tension differences 855 00:39:32,830 --> 00:39:37,470 are so slight, that instead of having the second phase float 856 00:39:37,470 --> 00:39:41,190 on the first phase, we have a dispersion, G. 857 00:39:41,190 --> 00:39:43,340 If you go to the dairy case, and you look at something 858 00:39:43,340 --> 00:39:46,160 called milk, you'll have the same thing. 859 00:39:46,160 --> 00:39:47,360 Why is milk milky? 860 00:39:47,360 --> 00:39:50,640 Because the fatty phase is a fine dispersion, and the 861 00:39:50,640 --> 00:39:54,480 particle sizes is dadadada, versus the wavelength of 862 00:39:54,480 --> 00:39:55,940 visible light, et cetera. 863 00:39:55,940 --> 00:40:00,070 Now if my phase diagram is correct, and I'm in here, if I 864 00:40:00,070 --> 00:40:03,310 keep adding ouzo, I should eventually emerge on this 865 00:40:03,310 --> 00:40:10,190 side, and instead of having a milky dispersion, I eventually 866 00:40:10,190 --> 00:40:13,240 should come here, and now I'll have a homogeneous, 867 00:40:13,240 --> 00:40:14,830 single-phase solution. 868 00:40:14,830 --> 00:40:17,300 But now it's going to be ouzo-rich, instead of 869 00:40:17,300 --> 00:40:18,550 water-rich. 870 00:40:20,310 --> 00:40:23,330 You never thought phase diagrams were interesting. 871 00:40:23,330 --> 00:40:24,580 You don't know. 872 00:40:29,660 --> 00:40:32,870 There we go. 873 00:40:32,870 --> 00:40:35,000 Je vous presente. 874 00:40:35,000 --> 00:40:36,350 There it is. 875 00:40:36,350 --> 00:40:39,430 So what we've done is, we've come across the thing. 876 00:40:39,430 --> 00:40:41,840 Yeah, that's good. 877 00:40:41,840 --> 00:40:43,300 Just put that there. 878 00:40:43,300 --> 00:40:48,670 Now, David, please, back to the slides. 879 00:40:48,670 --> 00:40:51,000 May I have the next slide, please? 880 00:40:51,000 --> 00:40:52,670 That's a joke. 881 00:40:52,670 --> 00:40:57,100 When you have these terrible speakers at conferences, they 882 00:40:57,100 --> 00:40:59,570 get up there, really nervous, and they stand up there, and 883 00:40:59,570 --> 00:41:01,180 the first thing they say is, may I have the 884 00:41:01,180 --> 00:41:02,730 first slide, please? 885 00:41:02,730 --> 00:41:04,970 That's sort of a gag among scientists. 886 00:41:04,970 --> 00:41:07,260 What's your opening statement? 887 00:41:07,260 --> 00:41:10,150 May I have the first slide, please? 888 00:41:10,150 --> 00:41:11,590 May I have the next slide, please? 889 00:41:11,590 --> 00:41:11,780 OK. 890 00:41:11,780 --> 00:41:13,240 So we've done this. 891 00:41:13,240 --> 00:41:14,940 All right. 892 00:41:14,940 --> 00:41:15,810 Now-- 893 00:41:15,810 --> 00:41:18,890 yeah, OK, this is just more. 894 00:41:18,890 --> 00:41:19,014 All right. 895 00:41:19,014 --> 00:41:20,390 So now I'm going to show you absinthe. 896 00:41:20,390 --> 00:41:21,460 Absinthe is the same thing. 897 00:41:21,460 --> 00:41:24,970 Absinthe also comes from the same family. 898 00:41:24,970 --> 00:41:28,020 And there's a little culture here. 899 00:41:28,020 --> 00:41:29,280 It contains wormwood. 900 00:41:29,280 --> 00:41:32,750 The wormwood was up at around 200, 250 parts per million. 901 00:41:32,750 --> 00:41:36,060 And what wormwood does, it's got a 902 00:41:36,060 --> 00:41:37,150 hormone they call thujone. 903 00:41:37,150 --> 00:41:40,900 And thujone antagonizes the gamma aminobutyric acid, which 904 00:41:40,900 --> 00:41:43,080 moderates firing of the neural synapses. 905 00:41:43,080 --> 00:41:46,440 Basically, we've got this GABA that regulates how-- our 906 00:41:46,440 --> 00:41:49,250 brains could work much faster than they do, 907 00:41:49,250 --> 00:41:51,880 but the GABA regulates. 908 00:41:51,880 --> 00:41:55,470 If GABA doesn't work, you can start moving so fast that you 909 00:41:55,470 --> 00:41:58,310 get muscle thing, and you get epileptic, is one example. 910 00:41:58,310 --> 00:42:02,050 But anyways, what it does, is if you drink this stuff, 911 00:42:02,050 --> 00:42:04,280 instead of being a stupid drunk, you become a very 912 00:42:04,280 --> 00:42:08,410 high-functioning, very alert drunk. 913 00:42:08,410 --> 00:42:10,470 And I'm going to show you what the consequence is in art. 914 00:42:10,470 --> 00:42:14,640 Anyways, the cultural piece here was that there was a 915 00:42:14,640 --> 00:42:19,430 destruction of the French wine industry in the 1800s due to a 916 00:42:19,430 --> 00:42:22,130 blight called Phylloxera. 917 00:42:22,130 --> 00:42:24,780 It's like a beetle, and it ate the vines. 918 00:42:24,780 --> 00:42:26,950 And in fact, the French wine industry was saved by the 919 00:42:26,950 --> 00:42:28,150 American wine industry. 920 00:42:28,150 --> 00:42:31,755 Vines from New York state were brought over, grafts were 921 00:42:31,755 --> 00:42:36,160 made, and virtually all French wine today is on American 922 00:42:36,160 --> 00:42:39,370 stock with the exception, occasionally you'll see 923 00:42:39,370 --> 00:42:40,650 something says vieille vin. 924 00:42:40,650 --> 00:42:41,460 Old vines. 925 00:42:41,460 --> 00:42:43,520 There was some areas that were spared. 926 00:42:43,520 --> 00:42:45,620 So what's that have to do with anything? 927 00:42:45,620 --> 00:42:48,860 It has to do with the fact that when the Phylloxera hit, 928 00:42:48,860 --> 00:42:52,030 the price of wine went very high, and the people at the 929 00:42:52,030 --> 00:42:55,230 bottom of the socioeconomic ladder couldn't afford wine. 930 00:42:55,230 --> 00:42:57,010 So they turn to absinthe. 931 00:42:57,010 --> 00:42:59,610 Absinthe was easily produced. 932 00:42:59,610 --> 00:43:02,600 Thirty years later, when the vines come back, the French 933 00:43:02,600 --> 00:43:05,350 wine industry wants to recapture the market. 934 00:43:05,350 --> 00:43:07,920 So there's a Faustian bargain between the French wine 935 00:43:07,920 --> 00:43:12,160 industry and the Women's Temperance Union to try to 936 00:43:12,160 --> 00:43:14,530 disparage absinthe. 937 00:43:14,530 --> 00:43:17,620 And there were a few major show trials that involved 938 00:43:17,620 --> 00:43:20,750 vicious murders in which it was alleged that the killer 939 00:43:20,750 --> 00:43:23,120 was deranged on absinthe. 940 00:43:23,120 --> 00:43:26,870 And with this, they slandered the name of absinthe so badly 941 00:43:26,870 --> 00:43:29,570 that it was eventually banned and literally 942 00:43:29,570 --> 00:43:30,990 taken off the market. 943 00:43:30,990 --> 00:43:32,000 I mean-- 944 00:43:32,000 --> 00:43:34,780 you know, we had the Rosalind Franklin commentary a few 945 00:43:34,780 --> 00:43:35,240 lectures ago. 946 00:43:35,240 --> 00:43:37,610 I hope I never read about you doing something like this in 947 00:43:37,610 --> 00:43:39,450 order to help your start-up company 948 00:43:39,450 --> 00:43:40,580 take over market share. 949 00:43:40,580 --> 00:43:43,880 That's not the way you're supposed to do it. 950 00:43:43,880 --> 00:43:44,650 Anyway, so what-- 951 00:43:44,650 --> 00:43:46,030 now, how did they drink it? 952 00:43:46,030 --> 00:43:47,940 They drank it by mixing-- 953 00:43:47,940 --> 00:43:50,050 so it's now back, but it's got very low levels 954 00:43:50,050 --> 00:43:51,420 of thujone, so it's-- 955 00:43:51,420 --> 00:43:53,240 David, may we go to this? 956 00:43:53,240 --> 00:43:55,200 So we're going to make a mix called the louche. 957 00:43:55,200 --> 00:43:56,090 It's a-- 958 00:43:56,090 --> 00:43:57,730 OK, here it is. 959 00:43:57,730 --> 00:43:59,005 And this stuff here is beautiful. 960 00:44:01,550 --> 00:44:04,950 Because it's a green color, a soft green color. 961 00:44:04,950 --> 00:44:06,710 And the French even have a name for it. 962 00:44:06,710 --> 00:44:09,660 They call it the green fairy, la fee verte. 963 00:44:09,660 --> 00:44:13,620 So this is what absinthe looks like. 964 00:44:13,620 --> 00:44:14,520 Beautiful. 965 00:44:14,520 --> 00:44:15,280 Very nice. 966 00:44:15,280 --> 00:44:17,950 And it's got the same kind of licorice smell to it. 967 00:44:17,950 --> 00:44:22,590 And so you make the louche by one part absinthe and five 968 00:44:22,590 --> 00:44:23,210 parts water. 969 00:44:23,210 --> 00:44:27,030 So this, at no upcharge, you get this glass. 970 00:44:27,030 --> 00:44:31,210 It's a beautiful piece of, you know, late 971 00:44:31,210 --> 00:44:32,860 Belle Epoque glassware. 972 00:44:32,860 --> 00:44:34,980 And the interesting thing is, these people were absolutely 973 00:44:34,980 --> 00:44:37,120 crazy, scientifically. 974 00:44:37,120 --> 00:44:40,180 And so what they did is, the markings on this glass are 975 00:44:40,180 --> 00:44:44,210 such that if you put absinthe up to this ring here, and then 976 00:44:44,210 --> 00:44:47,060 you put water the rest of the way, you get exactly the five 977 00:44:47,060 --> 00:44:49,220 to one ratio for louche. 978 00:44:49,220 --> 00:44:51,320 So you don't even have to measure. 979 00:44:51,320 --> 00:44:53,930 You just put like so. 980 00:44:53,930 --> 00:44:54,240 OK. 981 00:44:54,240 --> 00:44:55,060 Let's see. 982 00:44:55,060 --> 00:44:55,930 I'm going to get this right! 983 00:44:55,930 --> 00:44:57,180 It's science. 984 00:44:58,950 --> 00:45:01,610 Here's our distilled water. 985 00:45:01,610 --> 00:45:04,030 You see how it's milky? 986 00:45:04,030 --> 00:45:05,030 So there's the louche. 987 00:45:05,030 --> 00:45:11,390 And if you wanted to be a real hipster, you had this special 988 00:45:11,390 --> 00:45:13,320 Belle Epoque spoon. 989 00:45:13,320 --> 00:45:17,500 And what you'd put on top of this would be a sugar cube. 990 00:45:17,500 --> 00:45:19,400 You know, this is how it was done. 991 00:45:19,400 --> 00:45:20,960 You have to know some culture. 992 00:45:20,960 --> 00:45:21,500 You don't know. 993 00:45:21,500 --> 00:45:23,200 You've led sheltered lives. 994 00:45:23,200 --> 00:45:24,380 You pour it through here, like this. 995 00:45:24,380 --> 00:45:26,570 So now I'm going to show you the art. 996 00:45:26,570 --> 00:45:31,820 So David, may we cut to the slides again? 997 00:45:31,820 --> 00:45:35,110 So there's the louche. 998 00:45:35,110 --> 00:45:35,390 All right. 999 00:45:35,390 --> 00:45:36,150 So here's the poster. 1000 00:45:36,150 --> 00:45:36,710 Here's the man. 1001 00:45:36,710 --> 00:45:40,820 He's pouring the water through the slotted spoon with the 1002 00:45:40,820 --> 00:45:43,240 thing, and there's a very well-to-do lady, you can tell, 1003 00:45:43,240 --> 00:45:45,470 she's got a beautiful hat, and she's well-dressed. 1004 00:45:45,470 --> 00:45:48,610 And he's inviting her to join him for a glass of absinthe. 1005 00:45:48,610 --> 00:45:50,200 L'absinthe oxygenee. 1006 00:45:50,200 --> 00:45:51,230 That's the name of the company. 1007 00:45:51,230 --> 00:45:52,940 The oxygenated absinthe. 1008 00:45:52,940 --> 00:45:53,800 C'est ma sante. 1009 00:45:53,800 --> 00:45:55,050 This is my health. 1010 00:45:58,120 --> 00:46:01,490 Van Gogh painted this. 1011 00:46:01,490 --> 00:46:02,320 This is Picasso. 1012 00:46:02,320 --> 00:46:03,250 The absinthe drinker. 1013 00:46:03,250 --> 00:46:05,050 There's the absinthe again. 1014 00:46:05,050 --> 00:46:09,040 This is Picasso after many absinthes. 1015 00:46:09,040 --> 00:46:12,090 You can see the slotted spoon and the sugar cube. 1016 00:46:12,090 --> 00:46:13,550 What else is there? 1017 00:46:13,550 --> 00:46:16,750 That's up to you. 1018 00:46:16,750 --> 00:46:17,050 All right. 1019 00:46:17,050 --> 00:46:19,740 When you saw Moulin Rouge, you may not have known all of this 1020 00:46:19,740 --> 00:46:20,580 cultural history. 1021 00:46:20,580 --> 00:46:24,040 So now let's take a look at what's going on here. 1022 00:46:24,040 --> 00:46:26,890 There's the absinthe, and I think we've got a little-- 1023 00:46:26,890 --> 00:46:28,838 [VIDEO PLAYBACK] 1024 00:46:28,838 --> 00:46:32,247 -I don't even know if I am a true Bohemian revolutionary. 1025 00:46:32,247 --> 00:46:33,840 -Do you believe in beauty? 1026 00:46:33,840 --> 00:46:34,665 -Yes. 1027 00:46:34,665 --> 00:46:35,130 -Freedom? 1028 00:46:35,130 --> 00:46:35,786 -Yes, of course. 1029 00:46:35,786 --> 00:46:36,780 -Truth? 1030 00:46:36,780 --> 00:46:36,960 -Yes. 1031 00:46:36,960 --> 00:46:39,170 -Love? 1032 00:46:39,170 --> 00:46:39,970 -Love? 1033 00:46:39,970 --> 00:46:41,086 Love. 1034 00:46:41,086 --> 00:46:43,245 Above all things, I believe in love. 1035 00:46:43,245 --> 00:46:45,320 Love is like oxygen. 1036 00:46:45,320 --> 00:46:46,570 Love is a many-splendored thing-- 1037 00:46:51,866 --> 00:46:52,580 [END VIDEO PLAYBACK] 1038 00:46:52,580 --> 00:46:55,020 Love is like oxygen. 1039 00:46:55,020 --> 00:46:56,270 Chemistry is everywhere! 1040 00:47:00,400 --> 00:47:02,110 All right, so this is what happens eventually. 1041 00:47:02,110 --> 00:47:03,720 This is the poster. 1042 00:47:03,720 --> 00:47:04,950 This is from Switzerland. 1043 00:47:04,950 --> 00:47:06,560 October 7, 1910. 1044 00:47:06,560 --> 00:47:08,350 Gentleman, This Is the Hour! 1045 00:47:08,350 --> 00:47:11,020 And there's the clergyman with the Bible, and there's the 1046 00:47:11,020 --> 00:47:11,900 green fairy. 1047 00:47:11,900 --> 00:47:14,030 And she has a wand. 1048 00:47:14,030 --> 00:47:16,640 She's been stabbed, but she's lying here with a wand. 1049 00:47:16,640 --> 00:47:19,440 The wand is an opalescent wand, because this stuff is 1050 00:47:19,440 --> 00:47:20,220 opalescent. 1051 00:47:20,220 --> 00:47:22,390 Last thing I'll show you is some really, really cool 1052 00:47:22,390 --> 00:47:24,720 chemistry that you must remember. 1053 00:47:24,720 --> 00:47:26,360 When Toulouse-Lautrec drank-- 1054 00:47:26,360 --> 00:47:30,160 let's go back, David, to the thing. 1055 00:47:30,160 --> 00:47:33,320 So when Toulouse-Lautrec drank absinthe, and he drank lots of 1056 00:47:33,320 --> 00:47:36,370 it, he didn't like the milky color. 1057 00:47:36,370 --> 00:47:38,910 So he wanted to make the milky color disappear. 1058 00:47:38,910 --> 00:47:41,330 So I'm in the two-phase regime, and 1059 00:47:41,330 --> 00:47:42,760 I've got an oily phase. 1060 00:47:42,760 --> 00:47:44,910 And so how do I get rid of the oily phase? 1061 00:47:44,910 --> 00:47:46,800 What he did is he added cognac 1062 00:47:46,800 --> 00:47:48,200 And why did he add cognac? 1063 00:47:48,200 --> 00:47:52,550 Not because he was a hard-drinking alcoholic. 1064 00:47:52,550 --> 00:47:56,355 It's because if you've got a fat phase here, and you've got 1065 00:47:56,355 --> 00:47:58,500 an aqueous phase here, and if you add 1066 00:47:58,500 --> 00:48:00,030 alcohol, you've got CH3CH2OH. 1067 00:48:04,130 --> 00:48:09,680 This can bond to the water by a hydrogen bond, and this 1068 00:48:09,680 --> 00:48:12,330 aliphatic tail can stab the fat and 1069 00:48:12,330 --> 00:48:13,460 bring them into solution. 1070 00:48:13,460 --> 00:48:15,010 That's why you have these recipes. 1071 00:48:15,010 --> 00:48:17,810 Do you ever wonder why the recipe says, add brandy, or 1072 00:48:17,810 --> 00:48:20,350 add this, and then two steps later, it says flame? 1073 00:48:20,350 --> 00:48:22,010 You say, geez, I just put the brandy in, now 1074 00:48:22,010 --> 00:48:23,380 it's vaporizing away. 1075 00:48:23,380 --> 00:48:24,370 Isn't that kind of stupid? 1076 00:48:24,370 --> 00:48:25,630 No, it's not! 1077 00:48:25,630 --> 00:48:26,410 This is what you're doing. 1078 00:48:26,410 --> 00:48:27,360 You're cosolvating. 1079 00:48:27,360 --> 00:48:29,650 If you're ever making a cream sauce or something, and all of 1080 00:48:29,650 --> 00:48:31,570 a sudden, everything just curdles? 1081 00:48:31,570 --> 00:48:32,350 First you scream. 1082 00:48:32,350 --> 00:48:33,010 You go, ahhh! 1083 00:48:33,010 --> 00:48:34,290 Phase separation. 1084 00:48:34,290 --> 00:48:36,910 The second thing you do, is you get some of this, and you 1085 00:48:36,910 --> 00:48:37,960 cosolvate it. 1086 00:48:37,960 --> 00:48:38,940 All right. 1087 00:48:38,940 --> 00:48:40,440 So let's see what Lautrec did. 1088 00:48:40,440 --> 00:48:42,286 Lautrec-- 1089 00:48:42,286 --> 00:48:44,550 I might have to dilute the volume here. 1090 00:48:44,550 --> 00:48:45,600 We've got quite a lot in here. 1091 00:48:45,600 --> 00:48:47,230 So just to make the point. 1092 00:48:47,230 --> 00:48:49,520 So here's the louche, ad now we're going to add cognac. 1093 00:48:49,520 --> 00:48:51,720 He called this drink, Le Tremblement de Terre. 1094 00:48:51,720 --> 00:48:54,370 The earthquake. 1095 00:48:54,370 --> 00:48:57,680 He had a walking stick a meter long that was hollow, and it 1096 00:48:57,680 --> 00:48:58,470 always had this in it. 1097 00:48:58,470 --> 00:49:00,120 Look! 1098 00:49:00,120 --> 00:49:01,010 Look at that. 1099 00:49:01,010 --> 00:49:02,120 Isn't that something? 1100 00:49:02,120 --> 00:49:07,290 So now it's this beautiful blonde, golden color. 1101 00:49:07,290 --> 00:49:09,230 It's clear. 1102 00:49:09,230 --> 00:49:14,270 So this is all phase separation and so on. 1103 00:49:14,270 --> 00:49:15,910 At the end, it's all about chemistry. 1104 00:49:15,910 --> 00:49:16,210 All right. 1105 00:49:16,210 --> 00:49:18,830 We'll see you on Wednesday for our wrap-up. 1106 00:49:18,830 --> 00:49:20,080 Good.