1 00:00:15,966 --> 00:00:17,534 OK. 2 00:00:17,534 --> 00:00:20,270 Let's get started. 3 00:00:20,270 --> 00:00:21,805 How's everyone doing? 4 00:00:21,805 --> 00:00:22,672 Wonderful. 5 00:00:22,672 --> 00:00:24,607 Come on, let's do better than that. 6 00:00:24,607 --> 00:00:26,309 How is everyone doing? 7 00:00:26,309 --> 00:00:27,077 Wonderful! 8 00:00:27,077 --> 00:00:28,345 Thank you. 9 00:00:28,345 --> 00:00:31,481 Welcome to 3.091. 10 00:00:31,481 --> 00:00:33,717 This is the first day. 11 00:00:33,717 --> 00:00:35,385 And I'm really excited. 12 00:00:35,385 --> 00:00:37,253 I hope you are too. 13 00:00:37,253 --> 00:00:39,456 In this very first lecture, we're 14 00:00:39,456 --> 00:00:42,425 going to do a little bit of administration, 15 00:00:42,425 --> 00:00:46,229 tell you a little bit about the class and how it's set up. 16 00:00:46,229 --> 00:00:47,964 And then we'll give a little mini-- 17 00:00:47,964 --> 00:00:50,734 we'll have time for a mini lecture in the second part 18 00:00:50,734 --> 00:00:52,102 of the lecture today. 19 00:00:52,102 --> 00:00:54,938 So I thought I'd start by inducing me. 20 00:00:54,938 --> 00:00:57,007 My name is Jeff Grossman. 21 00:00:57,007 --> 00:00:59,809 I am in Course Three, that's the Department of Material Science 22 00:00:59,809 --> 00:01:01,411 and Engineering. 23 00:01:01,411 --> 00:01:04,447 My background, I went to Hopkins, undergrad, 24 00:01:04,447 --> 00:01:08,718 moved my way towards the west coast, Illinois PhD. 25 00:01:08,718 --> 00:01:11,488 And I did a post-doc at Berkeley. 26 00:01:11,488 --> 00:01:14,190 And then I came here to MIT about nine years ago 27 00:01:14,190 --> 00:01:16,493 when I joined the faculty. 28 00:01:16,493 --> 00:01:19,929 My own passion, my own interest in research 29 00:01:19,929 --> 00:01:26,269 is in materials for energy and water and chemical processes 30 00:01:26,269 --> 00:01:27,370 and separations. 31 00:01:27,370 --> 00:01:29,672 So I thought I'd just give you a little example of what 32 00:01:29,672 --> 00:01:30,373 I mean by that. 33 00:01:30,373 --> 00:01:32,741 So I get really excited about the ability 34 00:01:32,741 --> 00:01:35,712 to take the material and make it do something 35 00:01:35,712 --> 00:01:37,580 that it can't do now, but that it 36 00:01:37,580 --> 00:01:39,408 needs to do to solve a problem. 37 00:01:39,408 --> 00:01:40,616 Maybe it needs to be cheaper. 38 00:01:40,616 --> 00:01:43,652 Maybe it needs to be more efficient. 39 00:01:43,652 --> 00:01:46,256 So one example is in this material. 40 00:01:46,256 --> 00:01:49,125 This is a barrel of oil. 41 00:01:49,125 --> 00:01:51,694 And what we do today with this barrel of oil 42 00:01:51,694 --> 00:01:53,596 is we mostly burn it. 43 00:01:53,596 --> 00:01:54,898 A lot of what we do is burn it. 44 00:01:54,898 --> 00:01:56,648 Now if you do that, and you think about it 45 00:01:56,648 --> 00:02:01,471 in terms of energy, that's 159 liters of this material. 46 00:02:01,471 --> 00:02:02,906 And if you think about what you're 47 00:02:02,906 --> 00:02:05,975 carrying about as energy, you get 1.73 megawatt hours 48 00:02:05,975 --> 00:02:08,272 of energy out of that. 49 00:02:08,272 --> 00:02:10,814 But see, I like to think about materials, again, and ask them 50 00:02:10,814 --> 00:02:14,684 what they can do differently for me, for these problems. 51 00:02:14,684 --> 00:02:16,486 And so if you think about that and you say, 52 00:02:16,486 --> 00:02:18,688 well, OK, let's just take 1% of the carbon 53 00:02:18,688 --> 00:02:21,157 in that barrel of oil and do something with it. 54 00:02:21,157 --> 00:02:23,793 Let's make thin film solar cells. 55 00:02:23,793 --> 00:02:25,829 Well, if you do that and they're not very good, 56 00:02:25,829 --> 00:02:28,531 they're 5% efficient, they completely die in a year, 57 00:02:28,531 --> 00:02:31,634 you get 10,000 times as much energy over that year 58 00:02:31,634 --> 00:02:32,402 than burning it. 59 00:02:32,402 --> 00:02:33,837 So it's an example of what you can 60 00:02:33,837 --> 00:02:36,805 do when you think about using elements differently. 61 00:02:36,805 --> 00:02:39,709 That's what I get really excited about in my research. 62 00:02:39,709 --> 00:02:41,711 And that's just one example. 63 00:02:41,711 --> 00:02:45,482 You can take that same carbon and you 64 00:02:45,482 --> 00:02:48,118 can make a thermoelectric, that's on top. 65 00:02:48,118 --> 00:02:50,820 Or you can make the world's thinnest filter. 66 00:02:50,820 --> 00:02:53,089 That's a piece of graphene with a hole in it. 67 00:02:53,089 --> 00:02:56,559 And that's still working with just one element, carbon. 68 00:02:56,559 --> 00:02:57,411 All right? 69 00:02:57,411 --> 00:02:58,828 So there are many, many things you 70 00:02:58,828 --> 00:03:02,298 can do once you understand what these elements are 71 00:03:02,298 --> 00:03:03,733 and how they combine together. 72 00:03:03,733 --> 00:03:05,201 And that's what we're going to talk 73 00:03:05,201 --> 00:03:07,437 about in this class over the fall. 74 00:03:07,437 --> 00:03:08,938 How many elements are in your phone? 75 00:03:08,938 --> 00:03:10,807 Listen, we just talked about one element. 76 00:03:10,807 --> 00:03:13,843 Anybody know how many elements are in your phone? 77 00:03:13,843 --> 00:03:14,344 How many? 78 00:03:14,344 --> 00:03:15,812 Take a guess. 79 00:03:15,812 --> 00:03:17,380 Seven. 80 00:03:17,380 --> 00:03:19,315 27. 81 00:03:19,315 --> 00:03:20,617 OK, it depends. 82 00:03:20,617 --> 00:03:21,818 It depends. 83 00:03:21,818 --> 00:03:24,954 Do you have the Samsung? 84 00:03:24,954 --> 00:03:27,423 If you've got the Samsung whatever, 85 00:03:27,423 --> 00:03:28,591 it might light on fire. 86 00:03:28,591 --> 00:03:30,560 If you've got the newer one, it won't. 87 00:03:30,560 --> 00:03:31,561 Do you have an iPhone? 88 00:03:31,561 --> 00:03:32,362 Well you know what? 89 00:03:32,362 --> 00:03:34,364 In the iPhone, there's 63. 90 00:03:34,364 --> 00:03:39,402 63 elements. 91 00:03:39,402 --> 00:03:41,437 So we have these lectures in Course Three, 92 00:03:41,437 --> 00:03:42,772 they're called the wolf lecture. 93 00:03:42,772 --> 00:03:44,474 And I gave one a couple of years ago. 94 00:03:44,474 --> 00:03:45,708 If you're interested in hearing a little bit more 95 00:03:45,708 --> 00:03:47,710 about what I do or what some other people do who 96 00:03:47,710 --> 00:03:49,164 think about materials in this way, 97 00:03:49,164 --> 00:03:50,914 you can use Google wolf lecture and you'll 98 00:03:50,914 --> 00:03:53,249 get to some of the videos. 99 00:03:53,249 --> 00:03:55,952 And I'll mention it when they come around during the year. 100 00:03:55,952 --> 00:04:00,182 OK, so that's a little intro to me. 101 00:04:00,182 --> 00:04:01,057 What about the class? 102 00:04:01,057 --> 00:04:03,626 So as I said, the class-- at the heart of the class 103 00:04:03,626 --> 00:04:07,096 is kind of what I just described. 104 00:04:07,096 --> 00:04:11,634 But in order to do that, we need to know some very basic things. 105 00:04:11,634 --> 00:04:17,406 We need to know how atoms are arranged, 106 00:04:17,406 --> 00:04:20,136 the atomic arrangement right there. 107 00:04:20,136 --> 00:04:22,011 But we also need to know what atoms are there 108 00:04:22,011 --> 00:04:22,845 in the first place. 109 00:04:22,845 --> 00:04:27,050 So if we know that, if we know those things, 110 00:04:27,050 --> 00:04:30,086 then we can build, then we can build. 111 00:04:30,086 --> 00:04:31,321 We can get properties. 112 00:04:31,321 --> 00:04:32,722 We can get structure. 113 00:04:32,722 --> 00:04:34,357 We can get processing. 114 00:04:34,357 --> 00:04:35,425 We can get performance. 115 00:04:35,425 --> 00:04:37,619 And we can talk about how all of these things 116 00:04:37,619 --> 00:04:38,494 relate to each other. 117 00:04:38,494 --> 00:04:39,929 They're all correlated. 118 00:04:39,929 --> 00:04:41,698 If I change the processing of something, 119 00:04:41,698 --> 00:04:43,800 I change the properties. 120 00:04:43,800 --> 00:04:45,568 How do you know how it changes when you've 121 00:04:45,568 --> 00:04:46,836 got to know these things? 122 00:04:46,836 --> 00:04:48,972 And at the core of it all is really 123 00:04:48,972 --> 00:04:53,276 the thesis of this class, which is 124 00:04:53,276 --> 00:04:58,414 that the electronic structure-- 125 00:04:58,414 --> 00:05:02,047 Paul will be talking about this-- structure 126 00:05:02,047 --> 00:05:15,365 of the elements holds the key to understanding. 127 00:05:15,365 --> 00:05:20,436 That really is what this class is about. 128 00:05:20,436 --> 00:05:21,337 Holds the key. 129 00:05:21,337 --> 00:05:24,641 The electronic structure of the elements holds the key. 130 00:05:24,641 --> 00:05:26,542 That's what we're here to talk about. 131 00:05:26,542 --> 00:05:30,013 And the first part of this class is really the basic foundations 132 00:05:30,013 --> 00:05:32,282 of chemistry. 133 00:05:32,282 --> 00:05:34,217 Some of you may have seen some of this before. 134 00:05:34,217 --> 00:05:35,718 We're going to build these elements. 135 00:05:35,718 --> 00:05:36,586 We're going to talk about them. 136 00:05:36,586 --> 00:05:38,254 We're going to learn about the electrons 137 00:05:38,254 --> 00:05:40,123 and the electronic structure. 138 00:05:40,123 --> 00:05:43,035 But then we're going to make solids out of them 139 00:05:43,035 --> 00:05:44,827 and we're going to talk about what those do 140 00:05:44,827 --> 00:05:47,597 and how the chemistry relates to the solids 141 00:05:47,597 --> 00:05:50,800 and to the properties of those solids. 142 00:05:50,800 --> 00:05:52,335 Now, I want you to know, again, this 143 00:05:52,335 --> 00:05:54,404 is the sort of administrative introduction. 144 00:05:54,404 --> 00:05:56,039 You are not alone. 145 00:05:56,039 --> 00:06:01,577 On this journey, you have many, many resources. 146 00:06:01,577 --> 00:06:06,649 And we are here to help you, to help you learn this material 147 00:06:06,649 --> 00:06:09,352 and do the best you can. 148 00:06:09,352 --> 00:06:11,287 So first you have me. 149 00:06:11,287 --> 00:06:12,488 You have your TA. 150 00:06:12,488 --> 00:06:13,956 We'll talk about them in a second. 151 00:06:13,956 --> 00:06:15,391 You have Laura. 152 00:06:15,391 --> 00:06:17,393 Oh, we're going to talk about Laura in a second. 153 00:06:17,393 --> 00:06:19,529 You have the textbook and the internet. 154 00:06:19,529 --> 00:06:22,700 I hear there's stuff on the internet. 155 00:06:22,700 --> 00:06:23,700 And you have each other. 156 00:06:23,700 --> 00:06:27,036 And I really want you to work together. 157 00:06:27,036 --> 00:06:27,704 Thank you. 158 00:06:27,704 --> 00:06:28,871 Who said --that was... 159 00:06:28,871 --> 00:06:31,474 I was like, that hit made right here, right in the first 10 160 00:06:31,474 --> 00:06:33,609 minutes of class. 161 00:06:33,609 --> 00:06:35,411 So the textbook is Averill. 162 00:06:35,411 --> 00:06:38,047 It's a really good textbook. 163 00:06:38,047 --> 00:06:39,215 It's a really good textbook. 164 00:06:39,215 --> 00:06:40,683 Please use it. 165 00:06:40,683 --> 00:06:41,884 Please. 166 00:06:41,884 --> 00:06:43,238 It's available here. 167 00:06:43,238 --> 00:06:45,321 Notes, like I said, will be posted on the same day 168 00:06:45,321 --> 00:06:45,988 of each lecture. 169 00:06:45,988 --> 00:06:47,957 I'll post whatever you see on this screen. 170 00:06:47,957 --> 00:06:49,625 I will post. 171 00:06:49,625 --> 00:06:50,860 All right, good. 172 00:06:50,860 --> 00:06:52,061 The goody bag. 173 00:06:52,061 --> 00:06:57,300 So the goody bag is another part of your homework. 174 00:06:57,300 --> 00:07:01,504 And these will be given out nine weeks. 175 00:07:01,504 --> 00:07:03,639 So sort of like the quizzes. 176 00:07:03,639 --> 00:07:05,908 And in each goody bag, which I'm going 177 00:07:05,908 --> 00:07:09,212 to talk about in a second, there are things to do. 178 00:07:09,212 --> 00:07:15,551 This is a hands on compliment to 309.1 lecturers and all 179 00:07:15,551 --> 00:07:18,020 the other materials. 180 00:07:18,020 --> 00:07:24,060 Now, these goody bags are really important. 181 00:07:24,060 --> 00:07:26,229 And one of the two quiz questions, 182 00:07:26,229 --> 00:07:30,566 every week that there's a quiz, there are two questions. 183 00:07:30,566 --> 00:07:33,169 And one of them will be directly related to something 184 00:07:33,169 --> 00:07:35,004 that you're supposed to do in the goody bag. 185 00:07:35,004 --> 00:07:37,707 And in fact, we will most times ask 186 00:07:37,707 --> 00:07:42,378 you to bring something into the quiz that is in the bag. 187 00:07:42,378 --> 00:07:45,148 So don't throw it away and please do it. 188 00:07:45,148 --> 00:07:46,949 Because one of the two quiz questions 189 00:07:46,949 --> 00:07:48,751 will be very related to the goody bag. 190 00:07:48,751 --> 00:07:52,388 And the other will be related to problems, you know, lecture. 191 00:07:52,388 --> 00:07:55,057 Everything's related to lecture. 192 00:07:55,057 --> 00:07:57,370 But at least one will be related to what's in the bag. 193 00:07:57,370 --> 00:07:58,995 So this, we really take this seriously. 194 00:07:58,995 --> 00:08:02,231 This is a very important part of your homework. 195 00:08:02,231 --> 00:08:03,533 And oh, there it is. 196 00:08:03,533 --> 00:08:05,401 Some of which you need to bring to the quiz. 197 00:08:05,401 --> 00:08:08,304 And we'll tell you what that is before the quiz. 198 00:08:08,304 --> 00:08:11,073 I want to tell you a thing, though, because here's 199 00:08:11,073 --> 00:08:15,462 the thing, goody bags are-- it's a little bit of what's 200 00:08:15,462 --> 00:08:16,045 going on here? 201 00:08:16,045 --> 00:08:17,046 This is a lecture class. 202 00:08:17,046 --> 00:08:21,417 Why are we getting goody bags? 203 00:08:21,417 --> 00:08:27,423 And it's because I believe in the soul of MIT. 204 00:08:27,423 --> 00:08:29,659 I believe in the soul of MIT. 205 00:08:29,659 --> 00:08:35,231 And that is that we learn best by thinking and doing, 206 00:08:35,231 --> 00:08:37,332 by thinking and doing. 207 00:08:37,332 --> 00:08:39,235 And even though this is a lecture class, 208 00:08:39,235 --> 00:08:40,436 I still want you to do. 209 00:08:40,436 --> 00:08:42,738 I want you to have stuff in your hands 210 00:08:42,738 --> 00:08:44,440 so that you can play with the chemistry 211 00:08:44,440 --> 00:08:48,711 that we're learning about. 212 00:08:48,711 --> 00:08:50,480 Now, this goes back. 213 00:08:50,480 --> 00:08:51,581 I said the soul of MIT. 214 00:08:51,581 --> 00:08:52,648 What do I mean? 215 00:08:52,648 --> 00:08:59,989 This goes back, all the way back to before MIT was born, 1850s. 216 00:08:59,989 --> 00:09:02,285 You've got a group of really smart people. 217 00:09:02,285 --> 00:09:04,160 They're getting together and they're meeting. 218 00:09:04,160 --> 00:09:05,628 And they're saying, OK, we're going 219 00:09:05,628 --> 00:09:07,430 to start up a new university. 220 00:09:07,430 --> 00:09:09,665 What should we do? 221 00:09:09,665 --> 00:09:11,667 And they wrote out a plan. 222 00:09:11,667 --> 00:09:12,602 They wrote out a plan. 223 00:09:12,602 --> 00:09:14,060 And it's called the institute plan. 224 00:09:14,060 --> 00:09:15,838 That makes sense, 1860. 225 00:09:15,838 --> 00:09:17,992 It's a great read. 226 00:09:17,992 --> 00:09:19,575 But I want to pull out one part that's 227 00:09:19,575 --> 00:09:22,178 really important, that what they wanted 228 00:09:22,178 --> 00:09:28,050 to do with this great new institution was to do something 229 00:09:28,050 --> 00:09:31,754 that would serve the interests of the commerce and the arts, 230 00:09:31,754 --> 00:09:35,258 as well as of general education, call for the most 231 00:09:35,258 --> 00:09:37,693 earnest cooperation of intelligent culture 232 00:09:37,693 --> 00:09:40,429 with industrial pursuits, intelligent culture, 233 00:09:40,429 --> 00:09:42,131 industrial pursuits. 234 00:09:42,131 --> 00:09:44,901 That is Mens et Manus. 235 00:09:44,901 --> 00:09:47,937 That is Mens et Manus. 236 00:09:47,937 --> 00:09:50,506 Mind and Hand. 237 00:09:50,506 --> 00:09:55,778 It's so important to MIT that we put it on our logo. 238 00:09:55,778 --> 00:09:57,179 We put it on our logo. 239 00:09:57,179 --> 00:09:59,549 That's how important it is. 240 00:09:59,549 --> 00:10:04,787 We don't put some animal on our logo. 241 00:10:04,787 --> 00:10:09,458 We put what matters, mens et manus. 242 00:10:09,458 --> 00:10:14,430 We don't put the word truth. 243 00:10:14,430 --> 00:10:20,636 Veritas, veritas, I mean, I'm not going to name names, 244 00:10:20,636 --> 00:10:22,905 Harvard. 245 00:10:22,905 --> 00:10:26,742 But I mean, isn't that setting the bar kind of low? 246 00:10:26,742 --> 00:10:33,716 You know, were they lying before? 247 00:10:33,716 --> 00:10:35,017 I don't know. 248 00:10:35,017 --> 00:10:38,487 I'm not-- look, honestly I don't know. 249 00:10:38,487 --> 00:10:39,255 I don't know. 250 00:10:39,255 --> 00:10:43,159 But what I know is that what we know is that, of course, 251 00:10:43,159 --> 00:10:44,193 the goal is truth. 252 00:10:44,193 --> 00:10:48,831 The difference is, we know how to get it. 253 00:10:48,831 --> 00:10:51,968 Mens et manus is how to get it. 254 00:10:51,968 --> 00:10:54,303 Let me ask you a question. 255 00:10:54,303 --> 00:10:56,872 Why are you here? 256 00:10:56,872 --> 00:10:58,808 Not here in this classroom. 257 00:10:58,808 --> 00:11:01,310 I know you're in the classroom because you signed up for it. 258 00:11:01,310 --> 00:11:03,279 Why are you at MIT? 259 00:11:03,279 --> 00:11:06,983 Why are you here at MIT? 260 00:11:06,983 --> 00:11:10,486 I can tell you, you are here because you 261 00:11:10,486 --> 00:11:13,689 are some of the brightest, most gifted, most talented students 262 00:11:13,689 --> 00:11:15,891 on the planet. 263 00:11:15,891 --> 00:11:16,392 Right? 264 00:11:16,392 --> 00:11:17,994 Thank you, whoever said that. 265 00:11:17,994 --> 00:11:19,629 Agreement. 266 00:11:19,629 --> 00:11:21,864 That was like a like online. 267 00:11:21,864 --> 00:11:24,033 But you are here because you want 268 00:11:24,033 --> 00:11:28,537 to use those talents to make the world a better place. 269 00:11:28,537 --> 00:11:34,543 You are here because you know how to answer any question. 270 00:11:34,543 --> 00:11:37,747 But you are also here because you are going 271 00:11:37,747 --> 00:11:39,915 to experience a transition. 272 00:11:39,915 --> 00:11:42,318 You are going to experience a transition here. 273 00:11:42,318 --> 00:11:44,353 You are going to make the transition 274 00:11:44,353 --> 00:11:47,623 from knowing how to answer any question to knowing 275 00:11:47,623 --> 00:11:49,091 which question to ask. 276 00:11:49,091 --> 00:11:53,295 And that is the transition from student to scholar. 277 00:11:53,295 --> 00:11:54,797 That is MIT. 278 00:11:54,797 --> 00:11:58,300 That's mens et manus. 279 00:11:58,300 --> 00:12:01,737 Now, it's not easy. 280 00:12:01,737 --> 00:12:06,842 You don't come here-- nobody comes to MIT to phone it in. 281 00:12:06,842 --> 00:12:10,012 If universities were restaurants, 282 00:12:10,012 --> 00:12:13,416 this wouldn't be that fancy one where you go in and you order, 283 00:12:13,416 --> 00:12:15,551 and then somebody cooks and brings you your food. 284 00:12:15,551 --> 00:12:18,054 This would be the one where we all go back into the kitchen 285 00:12:18,054 --> 00:12:22,058 and together we make the best meal we've ever had. 286 00:12:22,058 --> 00:12:23,859 That's the MIT way. 287 00:12:23,859 --> 00:12:25,428 That's the MIT way. 288 00:12:25,428 --> 00:12:31,121 And it's not about-- you don't roam the halls here and bask 289 00:12:31,121 --> 00:12:34,637 in this reputation and think of it as some privilege 290 00:12:34,637 --> 00:12:40,609 to be here, because you are MIT's reputation. 291 00:12:40,609 --> 00:12:43,145 Freshmen, raise your hand. 292 00:12:43,145 --> 00:12:43,646 Yeah. 293 00:12:43,646 --> 00:12:46,482 Starting-- There's a few of you. 294 00:12:46,482 --> 00:12:51,087 Starting today, you are MIT's reputation. 295 00:12:51,087 --> 00:12:53,589 Starting today. 296 00:12:53,589 --> 00:12:54,457 It's on you. 297 00:12:54,457 --> 00:13:00,963 So we don't walk around these great halls and feel privilege. 298 00:13:00,963 --> 00:13:03,065 We feel responsibility. 299 00:13:03,065 --> 00:13:04,767 That's what it means to be here. 300 00:13:04,767 --> 00:13:08,237 OK? 301 00:13:08,237 --> 00:13:09,405 All right. 302 00:13:09,405 --> 00:13:10,272 Good. 303 00:13:10,272 --> 00:13:13,342 Well, now that we've got that all straightened out, 304 00:13:13,342 --> 00:13:13,943 let's move on. 305 00:13:13,943 --> 00:13:18,581 That's the end of my administrative stuff. 306 00:13:18,581 --> 00:13:23,452 And with the last 20, 25 minutes, 307 00:13:23,452 --> 00:13:29,058 I want to do a little bit of an introduction to chemistry. 308 00:13:29,058 --> 00:13:38,300 And I'm not going to ever test you on history. 309 00:13:38,300 --> 00:13:43,539 But I want to just kind of get ourselves in the mood 310 00:13:43,539 --> 00:13:45,875 by going back. 311 00:13:45,875 --> 00:13:50,946 So I'll give you a little bit of history here in a few slides. 312 00:13:50,946 --> 00:13:56,652 So we are interested in solid state chemistry 313 00:13:56,652 --> 00:14:00,723 because chemistry is that essential ingredient 314 00:14:00,723 --> 00:14:03,058 to understanding the natural world. 315 00:14:03,058 --> 00:14:07,563 And the solid state is the link between that and materials, 316 00:14:07,563 --> 00:14:09,765 and engineering. 317 00:14:09,765 --> 00:14:11,066 That is the link. 318 00:14:11,066 --> 00:14:14,236 And so we'll talk a lot about this all the time. 319 00:14:14,236 --> 00:14:16,071 Oh oh. 320 00:14:16,071 --> 00:14:18,974 Come on out, Jerome. 321 00:14:18,974 --> 00:14:21,777 But where did chemistry begin? 322 00:14:21,777 --> 00:14:26,782 OK, now hold on. 323 00:14:26,782 --> 00:14:27,449 I've got a pen. 324 00:14:27,449 --> 00:14:28,350 Oh no, I got a-- 325 00:14:28,350 --> 00:14:29,685 OK, that's better. 326 00:14:29,685 --> 00:14:32,588 I thought it was a pen. 327 00:14:32,588 --> 00:14:34,190 Where did it begin? 328 00:14:34,190 --> 00:14:36,358 Where did it begin? 329 00:14:36,358 --> 00:14:38,327 Well, people were mixing stuff a long time ago. 330 00:14:38,327 --> 00:14:40,362 But really, and there's some debate about this, 331 00:14:40,362 --> 00:14:42,832 you know, the word chem itself, you know, 332 00:14:42,832 --> 00:14:44,733 it may have come from chem, the land of chem, 333 00:14:44,733 --> 00:14:47,937 which means sort of the rich soil in Egypt. 334 00:14:47,937 --> 00:14:50,172 Or maybe it came from chemea in Greek, 335 00:14:50,172 --> 00:14:53,509 which meant sort of mixing and pouring together. 336 00:14:53,509 --> 00:14:55,444 But the point is that what they were doing was 337 00:14:55,444 --> 00:15:00,082 they were taking stuff and making other stuff out of it. 338 00:15:00,082 --> 00:15:03,185 That dagger there is from ancient Egypt. 339 00:15:03,185 --> 00:15:04,753 It's from around 3,000 BC. 340 00:15:04,753 --> 00:15:10,926 And the way they made that was by taking stuff from a meteor. 341 00:15:10,926 --> 00:15:13,028 It was iron and some nickel and some other things. 342 00:15:13,028 --> 00:15:14,230 But from a meteor. 343 00:15:14,230 --> 00:15:17,299 And they were able to make a really, really strong weapon 344 00:15:17,299 --> 00:15:18,534 out of it. 345 00:15:18,534 --> 00:15:21,270 They called those daggers from heaven. 346 00:15:21,270 --> 00:15:23,505 But the point is that what chemistry 347 00:15:23,505 --> 00:15:26,642 is about is it's about how you mix these things 348 00:15:26,642 --> 00:15:29,144 and what are you mixing in the first place. 349 00:15:29,144 --> 00:15:31,714 What was it that you took out of the meteor? 350 00:15:31,714 --> 00:15:33,616 And why did it make that instead of that? 351 00:15:33,616 --> 00:15:35,951 How did I get that dagger? 352 00:15:35,951 --> 00:15:37,753 That's really what this is about. 353 00:15:37,753 --> 00:15:41,190 And so if we go back to sort of the first people who 354 00:15:41,190 --> 00:15:43,459 really started discussing this, we 355 00:15:43,459 --> 00:15:46,295 start with Plato and Aristotle. 356 00:15:46,295 --> 00:15:54,003 And Plato had this idea, probably some of you 357 00:15:54,003 --> 00:15:57,306 may have heard it, so what is stuff made of? 358 00:15:57,306 --> 00:16:00,542 What is like the essence of things? 359 00:16:00,542 --> 00:16:03,245 They really thought about this and they debated it. 360 00:16:03,245 --> 00:16:08,751 And you know, Plato-- well, Plato said there's four things. 361 00:16:08,751 --> 00:16:10,252 And some of you may have heard this. 362 00:16:10,252 --> 00:16:12,855 There's earth. 363 00:16:12,855 --> 00:16:15,991 There's fire. 364 00:16:15,991 --> 00:16:18,227 There's air. 365 00:16:18,227 --> 00:16:23,832 And there's water. 366 00:16:23,832 --> 00:16:26,201 And everything is made out of that. 367 00:16:26,201 --> 00:16:30,572 Now, you can see that's a little limiting. 368 00:16:30,572 --> 00:16:32,474 Aristotle came along and said, wait a second. 369 00:16:32,474 --> 00:16:33,369 Hold on. 370 00:16:33,369 --> 00:16:35,911 If I look out into the stars, they don't seem to change much. 371 00:16:35,911 --> 00:16:38,047 So there must be something else that's not quote, 372 00:16:38,047 --> 00:16:41,383 "earthly and corruptible." 373 00:16:41,383 --> 00:16:42,451 And he called that ether. 374 00:16:42,451 --> 00:16:46,188 But anyway, the point is, it's hard to kind of explain 375 00:16:46,188 --> 00:16:47,256 everything with this. 376 00:16:47,256 --> 00:16:49,058 How are you going to build a world out of-- 377 00:16:49,058 --> 00:16:50,893 We can't even explain the Boston weather 378 00:16:50,893 --> 00:16:54,630 with just these four words. 379 00:16:54,630 --> 00:16:55,798 So it was limiting. 380 00:16:55,798 --> 00:17:01,804 But then along came these guys, Democritus and Leucippus, 381 00:17:01,804 --> 00:17:02,905 who was his teacher. 382 00:17:02,905 --> 00:17:07,376 And Democritus said, OK look, there's something fundamental. 383 00:17:07,376 --> 00:17:12,982 So Democritus, he said, look I believe there's something more 384 00:17:12,982 --> 00:17:15,416 than these four things. 385 00:17:15,416 --> 00:17:19,755 Democritus. 386 00:17:19,755 --> 00:17:22,891 And he said there are these things called atoms. 387 00:17:22,891 --> 00:17:25,194 So he was an atomist. 388 00:17:25,194 --> 00:17:30,332 And atom is indivisible. 389 00:17:30,332 --> 00:17:32,468 Indivisible, that's the meaning. 390 00:17:32,468 --> 00:17:39,141 Atomist in Greek, it meant indivisible, atom. 391 00:17:39,141 --> 00:17:40,876 And they fought about this. 392 00:17:40,876 --> 00:17:42,344 They fought about this a lot. 393 00:17:42,344 --> 00:17:45,881 And Plato, it's said, was so upset about Democritus 394 00:17:45,881 --> 00:17:49,985 that he wanted all of his books burned. 395 00:17:49,985 --> 00:17:53,822 That's a-- back in the day, that was a serious diss. 396 00:17:53,822 --> 00:17:58,627 It would be like if I blocked somebody on Instagram. 397 00:17:58,627 --> 00:17:59,261 Can I do that? 398 00:17:59,261 --> 00:17:59,928 Is that a thing? 399 00:17:59,928 --> 00:18:01,363 No, Snapchat. 400 00:18:01,363 --> 00:18:01,997 What? 401 00:18:01,997 --> 00:18:02,798 I don't know. 402 00:18:02,798 --> 00:18:03,332 I was right. 403 00:18:03,332 --> 00:18:04,433 See! 404 00:18:04,433 --> 00:18:07,136 That's how-- I'm blocking you. 405 00:18:07,136 --> 00:18:09,838 Burn your books. 406 00:18:09,838 --> 00:18:14,143 Seriously dissing each other. 407 00:18:14,143 --> 00:18:14,943 Democritus. 408 00:18:14,943 --> 00:18:19,048 Now, it really happened quickly from there. 409 00:18:19,048 --> 00:18:24,520 A mere 2,000 years later we get to modern chemistry. 410 00:18:24,520 --> 00:18:27,256 Why did it take 2,000 years? 411 00:18:27,256 --> 00:18:30,359 It took 2,000 years because we were missing something. 412 00:18:30,359 --> 00:18:31,794 So we had a lot of alchemy. 413 00:18:31,794 --> 00:18:33,595 The thing about alchemy, there are actually 414 00:18:33,595 --> 00:18:36,165 some really interesting discoveries in alchemy 415 00:18:36,165 --> 00:18:39,902 but they always tied it to something very non-rigorous, 416 00:18:39,902 --> 00:18:42,071 like oh, this works because of the phases 417 00:18:42,071 --> 00:18:46,375 of the moon or the tides. 418 00:18:46,375 --> 00:18:50,279 And so it really needed some rigorous way 419 00:18:50,279 --> 00:18:55,784 to study what things were made of, what things were made of. 420 00:18:55,784 --> 00:19:01,857 And that came, oh, inevitable that that might happen. 421 00:19:01,857 --> 00:19:02,591 Here we go. 422 00:19:02,591 --> 00:19:04,226 That came with the scientific method 423 00:19:04,226 --> 00:19:08,764 in the 1600s and Sir Francis Bacon. 424 00:19:08,764 --> 00:19:13,001 And I think a lot of you have seen the scientific method. 425 00:19:13,001 --> 00:19:14,636 But it was pivotal for chemistry. 426 00:19:14,636 --> 00:19:15,971 It was pivotal. 427 00:19:15,971 --> 00:19:17,606 Because it allowed people to think 428 00:19:17,606 --> 00:19:19,241 about this question of what stuff 429 00:19:19,241 --> 00:19:23,979 is made of but using a rigorous approach. 430 00:19:23,979 --> 00:19:26,448 Making observation, form a hypothesis, 431 00:19:26,448 --> 00:19:28,717 do an experiment, record. 432 00:19:28,717 --> 00:19:30,953 And that's what people started doing. 433 00:19:30,953 --> 00:19:33,122 That is what, for example, Robert Boyle 434 00:19:33,122 --> 00:19:36,458 did, one of the earlier ones to think about things 435 00:19:36,458 --> 00:19:37,826 and talk about the element. 436 00:19:37,826 --> 00:19:40,095 They were all going back to thinking 437 00:19:40,095 --> 00:19:44,733 about these same issues, what are things made of? 438 00:19:44,733 --> 00:19:48,237 An element can't be broken down into two or more 439 00:19:48,237 --> 00:19:51,173 simpler substances by chemical means. 440 00:19:51,173 --> 00:19:52,074 So he was at that. 441 00:19:52,074 --> 00:19:54,109 He was going for that core. 442 00:19:54,109 --> 00:19:55,744 What is at the core? 443 00:19:55,744 --> 00:20:00,249 Oh, and then you had Priestly. 444 00:20:00,249 --> 00:20:06,421 Priestly discovered oxygen and he did it by burning things. 445 00:20:06,421 --> 00:20:09,224 He did it by burning things. 446 00:20:09,224 --> 00:20:15,664 Just mentioning that word makes me want to put those on. 447 00:20:15,664 --> 00:20:19,234 And so he really studied combustion. 448 00:20:19,234 --> 00:20:22,137 He studied these reactions that were happening with oxygen 449 00:20:22,137 --> 00:20:25,307 and carbon containing matter. 450 00:20:25,307 --> 00:20:27,009 It was combustion. 451 00:20:27,009 --> 00:20:27,809 So he burned stuff. 452 00:20:27,809 --> 00:20:28,710 He burned this. 453 00:20:28,710 --> 00:20:29,611 He burned that. 454 00:20:29,611 --> 00:20:30,245 He burned that. 455 00:20:30,245 --> 00:20:32,948 And he said, what happens when I do that? 456 00:20:32,948 --> 00:20:34,016 That was another way. 457 00:20:34,016 --> 00:20:38,954 Priestly-- sorry, Boyle played with pressure and volume. 458 00:20:38,954 --> 00:20:40,355 Pressure and volume relationships 459 00:20:40,355 --> 00:20:42,558 for gases, that was his way to try to get 460 00:20:42,558 --> 00:20:43,892 at what things are made of. 461 00:20:43,892 --> 00:20:47,563 Priestley wanted to blow stuff up. 462 00:20:47,563 --> 00:20:51,526 Oh, and he also worked with beer. 463 00:20:51,526 --> 00:20:52,734 He actually worked with beer. 464 00:20:52,734 --> 00:20:55,170 And he discovered that the same gas that 465 00:20:55,170 --> 00:20:57,739 comes out of fermenting beer is the gas that 466 00:20:57,739 --> 00:21:00,008 comes out of combusting. 467 00:21:00,008 --> 00:21:03,278 So you got a guy who's working on lighting stuff 468 00:21:03,278 --> 00:21:06,081 on fire and beer. 469 00:21:06,081 --> 00:21:08,750 And you can imagine maybe that wasn't going 470 00:21:08,750 --> 00:21:11,086 to be a good day at some point. 471 00:21:11,086 --> 00:21:13,789 And what happened is, actually, his experiments did-- 472 00:21:13,789 --> 00:21:17,559 this is true, they slowed down when he fell into a vat of beer 473 00:21:17,559 --> 00:21:20,262 during one of his experiments. 474 00:21:20,262 --> 00:21:23,465 Now, the thing is, though, that he studied combustion. 475 00:21:23,465 --> 00:21:26,501 And that makes me think about combustion. 476 00:21:26,501 --> 00:21:32,541 And I feel like oh oh, I feel like this 477 00:21:32,541 --> 00:21:41,083 is a good time for my goody bag, which is to illustrate a point. 478 00:21:41,083 --> 00:21:47,055 Oh, thank you, Jerome. 479 00:21:47,055 --> 00:21:49,291 That's going to some feed somewhere. 480 00:21:49,291 --> 00:21:54,196 OK, now the thing is that when you go to a restaurant 481 00:21:54,196 --> 00:21:56,531 and they have real candles, I get really happy about it. 482 00:21:56,531 --> 00:22:00,469 We'll tell candle stories later in the term as well. 483 00:22:00,469 --> 00:22:02,371 And this is what you're doing. 484 00:22:02,371 --> 00:22:04,873 You are lighting a candle on fire. 485 00:22:04,873 --> 00:22:08,243 Now, when you do that, you see, here's the thing. 486 00:22:08,243 --> 00:22:11,079 You're actually-- I don't want you to think about it 487 00:22:11,079 --> 00:22:12,414 as lighting a candle. 488 00:22:12,414 --> 00:22:14,983 I want you to now from now on think about it 489 00:22:14,983 --> 00:22:16,704 as lighting C25H52. 490 00:22:16,704 --> 00:22:18,287 And in fact, if you go to a restaurant 491 00:22:18,287 --> 00:22:20,188 and you want to ask them if they have real candles, 492 00:22:20,188 --> 00:22:21,323 I don't care if you're out with friends 493 00:22:21,323 --> 00:22:23,492 or maybe you're on a date, raise your hand. 494 00:22:23,492 --> 00:22:27,596 Ask the waiter and say, do you have any C25H52? 495 00:22:27,596 --> 00:22:31,566 And see if they know, see if they've taken some chemistry. 496 00:22:31,566 --> 00:22:33,268 What you're doing is you're doing that. 497 00:22:33,268 --> 00:22:35,904 You're combusting that fuel. 498 00:22:35,904 --> 00:22:39,574 See, the whole world runs by lighting things on fire. 499 00:22:39,574 --> 00:22:41,743 You could light propane on fire. 500 00:22:41,743 --> 00:22:44,780 Or you could light hydrogen on fire. 501 00:22:44,780 --> 00:22:49,051 That's where we said, yo, hands on is a good way to learn. 502 00:22:49,051 --> 00:22:50,319 So let's see what that's like. 503 00:22:50,319 --> 00:22:52,220 There's the candle, which is tilting. 504 00:22:52,220 --> 00:22:54,356 I'm watching it. 505 00:22:54,356 --> 00:22:55,390 Really? 506 00:22:55,390 --> 00:22:58,293 Oh, OK. 507 00:22:58,293 --> 00:23:00,228 Or you could light hydrogen on fire. 508 00:23:00,228 --> 00:23:04,099 And if you do that, this is what happens. 509 00:23:04,099 --> 00:23:06,001 So, OK, let's do that again. 510 00:23:06,001 --> 00:23:09,304 These bubbles aren't-- oh, I should have kept this on. 511 00:23:09,304 --> 00:23:12,641 There we go. 512 00:23:12,641 --> 00:23:16,478 That's really, really fun. 513 00:23:16,478 --> 00:23:17,412 But I'm going to stop. 514 00:23:17,412 --> 00:23:19,356 Oh, I'm not going to stop because you just 515 00:23:19,356 --> 00:23:20,148 turned it on again. 516 00:23:20,148 --> 00:23:23,518 Now you're coaxing me to do more. 517 00:23:23,518 --> 00:23:24,820 Well, these are bigger bubbles. 518 00:23:24,820 --> 00:23:25,903 These are bigger boulders. 519 00:23:25,903 --> 00:23:28,423 Let's see if this gets a nice flame. 520 00:23:28,423 --> 00:23:30,625 Oh, thank you. 521 00:23:30,625 --> 00:23:32,961 There we go. 522 00:23:32,961 --> 00:23:40,035 OK, now that's my goody bag for today. 523 00:23:40,035 --> 00:23:41,903 We run our world by doing this, I mean, 524 00:23:41,903 --> 00:23:46,141 not by lighting hydrogen bubbles on fire, 525 00:23:46,141 --> 00:23:49,411 but when you put your phone in to charge it, 526 00:23:49,411 --> 00:23:50,412 you are lighting a fire. 527 00:23:50,412 --> 00:23:51,120 Think about that. 528 00:23:51,120 --> 00:23:53,915 You might not feel it. 529 00:23:53,915 --> 00:23:54,416 You are. 530 00:23:54,416 --> 00:23:56,251 No, I'm-- I love that reaction. 531 00:23:56,251 --> 00:23:57,319 I love that reaction. 532 00:23:57,319 --> 00:23:58,854 You are lighting a fire. 533 00:23:58,854 --> 00:24:01,723 It may not be you, but somebody else's down the street 534 00:24:01,723 --> 00:24:03,058 at a power plant. 535 00:24:03,058 --> 00:24:05,227 This is how we run our world, we burn things. 536 00:24:05,227 --> 00:24:09,030 And so this study of combustion was extremely important. 537 00:24:09,030 --> 00:24:13,402 And it's going to be our first reaction. 538 00:24:13,402 --> 00:24:14,936 So what's happening? 539 00:24:14,936 --> 00:24:20,409 When you light C25H52 on fire, what's happening 540 00:24:20,409 --> 00:24:21,943 is that you're reacting. 541 00:24:21,943 --> 00:24:25,387 You're doing-- remember, Priestley 542 00:24:25,387 --> 00:24:30,719 discovered H52 plus oxygen. He discovered oxygen. 543 00:24:30,719 --> 00:24:35,257 And he also, remember, this comes off of beer too. 544 00:24:35,257 --> 00:24:38,860 He also discovered these other gases coming out. 545 00:24:38,860 --> 00:24:41,029 Right? 546 00:24:41,029 --> 00:24:43,999 And that's the chemical reaction. 547 00:24:43,999 --> 00:24:46,134 Is it the chemical reaction? 548 00:24:46,134 --> 00:24:49,070 It's not done yet. 549 00:24:49,070 --> 00:24:50,238 It's not balanced. 550 00:24:50,238 --> 00:24:52,140 It's not balanced. 551 00:24:52,140 --> 00:24:54,242 Mass is being lost left and right. 552 00:24:54,242 --> 00:24:56,211 Not OK. 553 00:24:56,211 --> 00:24:57,312 Not OK. 554 00:24:57,312 --> 00:25:00,382 So we must, when we write down things 555 00:25:00,382 --> 00:25:04,986 that happen in chemistry like a reaction, we must find balance. 556 00:25:04,986 --> 00:25:07,622 It's also important in life. 557 00:25:07,622 --> 00:25:09,524 But it's very important in chemistry. 558 00:25:09,524 --> 00:25:13,795 And so if you balance this, you're going to put a 2. 559 00:25:13,795 --> 00:25:18,533 Because here's the deal and I'll talk about this more in a sec, 560 00:25:18,533 --> 00:25:29,077 C25H52 plus-- anybody know how many O2s? 561 00:25:29,077 --> 00:25:32,180 38, whoever said that, 38 is going 562 00:25:32,180 --> 00:25:43,225 to go to 25CO2 plus 26H2O. 563 00:25:43,225 --> 00:25:46,027 These are the kinds of things that are perfect, 564 00:25:46,027 --> 00:25:49,464 perfect to keep doing exercises on though your problems, 565 00:25:49,464 --> 00:25:53,368 through your goody bags, in your recitation. 566 00:25:53,368 --> 00:25:56,071 These are exactly the-- how did you do that? 567 00:25:56,071 --> 00:25:57,906 If you don't know, you will soon. 568 00:25:57,906 --> 00:26:03,211 You'll get help, practice. 569 00:26:03,211 --> 00:26:04,746 I know, I know. 570 00:26:04,746 --> 00:26:07,148 I wrote this down. 571 00:26:07,148 --> 00:26:09,918 I'm just testing you. 572 00:26:09,918 --> 00:26:11,152 I made a mistake. 573 00:26:11,152 --> 00:26:16,558 Because the 2 was supposed to go to the propane one 574 00:26:16,558 --> 00:26:19,127 because I wanted to write that one and I got excited. 575 00:26:19,127 --> 00:26:22,597 And I went to that instead. 576 00:26:22,597 --> 00:26:24,599 And that would be 13O2. 577 00:26:24,599 --> 00:26:30,805 And that would be 8CO2, and so on, 10H2O. 578 00:26:30,805 --> 00:26:33,008 These are balanced. 579 00:26:33,008 --> 00:26:35,443 These are balanced. 580 00:26:35,443 --> 00:26:40,882 And balancing reactions is important. 581 00:26:40,882 --> 00:26:41,383 Why? 582 00:26:41,383 --> 00:26:46,688 Because it balances the mass and it tells us something else. 583 00:26:46,688 --> 00:26:49,090 Once we count atoms, you'll see. 584 00:26:49,090 --> 00:26:52,694 We're going to count atoms on Friday. 585 00:26:52,694 --> 00:26:56,531 But it's telling us that you can't just lose stuff. 586 00:26:56,531 --> 00:26:57,732 You can't just lose stuff. 587 00:26:57,732 --> 00:26:58,800 You've got to have the-- 588 00:26:58,800 --> 00:27:02,737 Oh, and that, by the way, is what-- 589 00:27:02,737 --> 00:27:03,939 Lavoisier, Lavoisier. 590 00:27:03,939 --> 00:27:05,307 Where is Jerome? 591 00:27:05,307 --> 00:27:06,741 Oh, yeah. 592 00:27:06,741 --> 00:27:07,876 No. 593 00:27:07,876 --> 00:27:08,376 Shoot. 594 00:27:08,376 --> 00:27:10,312 Isn't that butane, not propane? 595 00:27:10,312 --> 00:27:11,279 Butane not propane. 596 00:27:11,279 --> 00:27:13,048 It very well might have been. 597 00:27:13,048 --> 00:27:15,050 C4 H10, yes. 598 00:27:15,050 --> 00:27:16,318 I believe that is butane. 599 00:27:16,318 --> 00:27:20,755 Thank you. 600 00:27:20,755 --> 00:27:22,557 Oh, Jerome, come back. 601 00:27:22,557 --> 00:27:25,226 Jerome helps the class and he helps my French. 602 00:27:25,226 --> 00:27:26,661 Lavoisier? 603 00:27:26,661 --> 00:27:28,663 No. 604 00:27:28,663 --> 00:27:31,533 OK, say it. 605 00:27:31,533 --> 00:27:35,403 Lavoisier. 606 00:27:35,403 --> 00:27:37,238 OK, I tried. 607 00:27:37,238 --> 00:27:43,211 But now he said, look, you've got to conserve mass. 608 00:27:43,211 --> 00:27:47,315 You can't lose-- you can't create or destroy matter 609 00:27:47,315 --> 00:27:48,817 when you do chemistry. 610 00:27:48,817 --> 00:27:52,754 When you do this, when you do this you cannot create 611 00:27:52,754 --> 00:27:56,691 or destroy matter. 612 00:27:56,691 --> 00:28:03,498 Conservation of mass, Lavoisier. 613 00:28:03,498 --> 00:28:06,767 It means that if I-- you know, you get a little more 614 00:28:06,767 --> 00:28:10,805 than that, see this is balancing. 615 00:28:10,805 --> 00:28:15,577 But you also can think about whether you have anything-- 616 00:28:15,577 --> 00:28:18,580 I probably should blow that out. 617 00:28:18,580 --> 00:28:23,318 Whether you have anything-- did you have too much, too little? 618 00:28:23,318 --> 00:28:24,519 Did I mix it just right? 619 00:28:24,519 --> 00:28:27,184 So like if you take-- let's take another reaction just 620 00:28:27,184 --> 00:28:28,023 as an example. 621 00:28:28,023 --> 00:28:39,067 If I mix iron and oxygen to make ferric oxide, oh, not balanced. 622 00:28:39,067 --> 00:28:43,438 Two, three, four. 623 00:28:43,438 --> 00:28:48,677 And I tell you, for example, that I've got 10 grams of iron 624 00:28:48,677 --> 00:28:55,083 reacts with, let's see-- 625 00:28:55,083 --> 00:28:57,085 OK, I'm going to give it to you a different way. 626 00:28:57,085 --> 00:29:04,325 I'm going to say that it gives you, reacts with O2 to give 627 00:29:04,325 --> 00:29:11,533 18.2 grams of FE203. 628 00:29:11,533 --> 00:29:14,903 This is an example from the textbook. 629 00:29:14,903 --> 00:29:17,330 Then I know because of conservation 630 00:29:17,330 --> 00:29:25,776 of mass from Lavoisier that 8.2 grams-- if this reacts fully, 631 00:29:25,776 --> 00:29:30,485 right, if iron reacts fully, it all goes away. 632 00:29:30,485 --> 00:29:31,886 There's none left. 633 00:29:31,886 --> 00:29:35,490 Then I must have, if I got 18.2 grams of ferric acid, 634 00:29:35,490 --> 00:29:38,760 I must have reacted 8.2 grams of oxygen. 635 00:29:38,760 --> 00:29:40,895 That's conservation of mass. 636 00:29:40,895 --> 00:29:44,032 But there's another thing you can do with this. 637 00:29:44,032 --> 00:29:53,041 So I must have reacted 8.2 grams of oxygen. 638 00:29:53,041 --> 00:29:56,945 But there's another thing because if I started, you know, 639 00:29:56,945 --> 00:30:09,324 if I started now with 10 grams of O2 and 10 grams of iron, 640 00:30:09,324 --> 00:30:12,393 aha, I'm going to have excess. 641 00:30:12,393 --> 00:30:13,528 I know that. 642 00:30:13,528 --> 00:30:14,429 I know that now. 643 00:30:14,429 --> 00:30:15,497 I'm going to have excess. 644 00:30:15,497 --> 00:30:18,833 And the thing is that there's something that's limiting here. 645 00:30:18,833 --> 00:30:21,936 What's in excess? 646 00:30:21,936 --> 00:30:25,073 The oxygen because I started with the same amount of iron. 647 00:30:25,073 --> 00:30:27,375 There is more-- but that means that we've 648 00:30:27,375 --> 00:30:33,506 got another term, which is that iron is the limiting reagent. 649 00:30:33,506 --> 00:30:34,048 You see that? 650 00:30:34,048 --> 00:30:40,688 Because now I'm limited, meaning this reaction 651 00:30:40,688 --> 00:30:43,825 goes and goes and goes and something runs out first. 652 00:30:43,825 --> 00:30:47,328 That is the limiting reagent. 653 00:30:47,328 --> 00:30:51,633 And this was just by thinking about Lavoisier's conservation 654 00:30:51,633 --> 00:30:52,934 of mass. 655 00:30:52,934 --> 00:30:55,937 I can't create or destroy atoms in a reaction, 656 00:30:55,937 --> 00:30:57,238 not in this class. 657 00:30:57,238 --> 00:30:58,807 You can take nuclear somewhere else. 658 00:30:58,807 --> 00:30:59,774 But not here. 659 00:30:59,774 --> 00:31:02,443 Here we don't destroy or create matter. 660 00:31:02,443 --> 00:31:04,546 Limiting reagent, balancing reactions, 661 00:31:04,546 --> 00:31:09,150 very, very fundamental first chemical concepts. 662 00:31:09,150 --> 00:31:12,687 Now, these guys were playing around with stuff 663 00:31:12,687 --> 00:31:14,756 and really trying to figure out, again, 664 00:31:14,756 --> 00:31:17,458 they're going back to Democritus. 665 00:31:17,458 --> 00:31:22,674 What are these indivisible elements, atoms, what are they? 666 00:31:22,674 --> 00:31:24,799 And all these guys were starting to mess with that. 667 00:31:24,799 --> 00:31:26,661 Once they had the scientific method, 668 00:31:26,661 --> 00:31:28,036 they were willing to go very far. 669 00:31:28,036 --> 00:31:32,507 Here's Lavoisier's list, 33 elements. 670 00:31:32,507 --> 00:31:35,143 And he tried to organize them. 671 00:31:35,143 --> 00:31:38,513 And in some cases, he succeeded fairly well. 672 00:31:38,513 --> 00:31:39,113 Look at this. 673 00:31:39,113 --> 00:31:42,116 This is a, OK, where is Jerome? 674 00:31:42,116 --> 00:31:48,156 This is a Tableau des Substances... 675 00:31:48,156 --> 00:31:50,658 No, not even close. 676 00:31:50,658 --> 00:31:53,695 But look, "Simples..." 677 00:31:53,695 --> 00:31:58,233 Simple, fundamental atoms. 678 00:31:58,233 --> 00:32:00,635 What are those things that we're mixing together 679 00:32:00,635 --> 00:32:04,339 that we've been mixing together for thousands of years? 680 00:32:04,339 --> 00:32:06,875 What is that thing I'm pulling out of this oar 681 00:32:06,875 --> 00:32:08,710 and making stuff out of? 682 00:32:08,710 --> 00:32:13,281 And he was trying to classify them using these experiments. 683 00:32:13,281 --> 00:32:19,454 And some of these are actually really good discoveries. 684 00:32:19,454 --> 00:32:21,456 I want you to experience this. 685 00:32:21,456 --> 00:32:23,725 I want you to go back to this time. 686 00:32:23,725 --> 00:32:27,362 And that is what the first goody bag is about. 687 00:32:27,362 --> 00:32:30,098 So what I have given you in this goody bag 688 00:32:30,098 --> 00:32:36,237 is the most accurate measuring device ever created and branded 689 00:32:36,237 --> 00:32:37,939 309.1. 690 00:32:37,939 --> 00:32:40,909 It's a ruler. 691 00:32:40,909 --> 00:32:42,310 I've given you five metal strips. 692 00:32:42,310 --> 00:32:45,013 And I want you to pretend that you don't know what these are. 693 00:32:45,013 --> 00:32:47,649 How do you find out? 694 00:32:47,649 --> 00:32:52,987 You do nothing with fire, nothing. 695 00:32:52,987 --> 00:32:56,157 But I gave you vinegar. 696 00:32:56,157 --> 00:32:58,059 And you do lots with vinegar. 697 00:32:58,059 --> 00:32:58,826 Pour it on them. 698 00:32:58,826 --> 00:32:59,928 Measure it, weigh it. 699 00:32:59,928 --> 00:33:01,529 Look at it. 700 00:33:01,529 --> 00:33:02,764 Shiny, not shiny. 701 00:33:02,764 --> 00:33:04,832 Different color, densities. 702 00:33:04,832 --> 00:33:08,636 Think about what the differences are. 703 00:33:08,636 --> 00:33:10,338 And I want to put you back in that time. 704 00:33:10,338 --> 00:33:12,373 And I want to make a point here, goody bags 705 00:33:12,373 --> 00:33:14,442 are not just about the questions I ask. 706 00:33:14,442 --> 00:33:18,212 I hope that you think even beyond the Goody bag. 707 00:33:18,212 --> 00:33:21,282 So if you use that vinegar and one of those things reacts, 708 00:33:21,282 --> 00:33:26,020 let's just suppose, with the vinegar, 709 00:33:26,020 --> 00:33:28,723 think about what that is and maybe vinegar is a test. 710 00:33:28,723 --> 00:33:30,658 Maybe it's a test and you can react-- 711 00:33:30,658 --> 00:33:33,962 you can pour vinegar and make reactions with other things. 712 00:33:33,962 --> 00:33:36,264 Maybe you should be thinking about where that thing is 713 00:33:36,264 --> 00:33:38,599 in the Infinite Corridor and the whole Infinite Corridor 714 00:33:38,599 --> 00:33:40,301 should smell like vinegar. 715 00:33:40,301 --> 00:33:46,107 But we won't tell President Reif about that. 716 00:33:46,107 --> 00:33:49,711 But that's what I mean, maybe not the Infinite-- but explore. 717 00:33:49,711 --> 00:33:50,912 These are meant to be-- 718 00:33:50,912 --> 00:33:54,115 I want you to really use these as an adventure. 719 00:33:54,115 --> 00:33:56,718 You know, think outside the box. 720 00:33:56,718 --> 00:33:59,587 So you've got this most accurate measuring device. 721 00:33:59,587 --> 00:34:01,189 You've got these strips of pipette. 722 00:34:01,189 --> 00:34:03,458 And you've got some gloves. 723 00:34:03,458 --> 00:34:07,662 And that is your first goody bag. 724 00:34:07,662 --> 00:34:11,232 OK, now though the last thing that I'm 725 00:34:11,232 --> 00:34:13,400 going to tell you about is why this matters. 726 00:34:13,400 --> 00:34:17,005 And just like the goody bags, when I started teaching class 727 00:34:17,005 --> 00:34:21,409 three years ago, I wanted to also protect 728 00:34:21,409 --> 00:34:24,846 a certain fundamental part of each lecture. 729 00:34:24,846 --> 00:34:27,514 And I call it my why this matters moment. 730 00:34:27,514 --> 00:34:30,784 Sometimes it goes on for more than a moment. 731 00:34:30,784 --> 00:34:33,755 But I really, really want every lecture 732 00:34:33,755 --> 00:34:38,226 to connect what we just learned to a big picture. 733 00:34:38,226 --> 00:34:39,860 Most of the time, it's some application 734 00:34:39,860 --> 00:34:42,463 or some global challenge. 735 00:34:42,463 --> 00:34:45,699 Right I want you to see those connections, 736 00:34:45,699 --> 00:34:47,601 that what you're learning is directly 737 00:34:47,601 --> 00:34:51,005 relevant to some big thing. 738 00:34:51,005 --> 00:34:53,875 So my why this matters moment is really related 739 00:34:53,875 --> 00:34:56,777 to these discoveries themselves. 740 00:34:56,777 --> 00:34:58,579 Please give me till 11:55. 741 00:34:58,579 --> 00:35:00,709 I will always let you go on time, 11:55. 742 00:35:00,709 --> 00:35:02,417 But please don't start putting stuff away 743 00:35:02,417 --> 00:35:04,485 because it's distracting to everybody. 744 00:35:04,485 --> 00:35:08,856 So two and a half minutes. 745 00:35:08,856 --> 00:35:13,594 We name the age we live in often by the element, by the atom, 746 00:35:13,594 --> 00:35:17,498 by the material, by the material that 747 00:35:17,498 --> 00:35:20,735 was most useful at the time. 748 00:35:20,735 --> 00:35:24,372 The Stone Age, the Bronze Age, the Iron Age. 749 00:35:24,372 --> 00:35:26,607 I would say we've moved through the industrial age, 750 00:35:26,607 --> 00:35:28,910 the age of plastics, the age of silicon. 751 00:35:28,910 --> 00:35:31,646 As a material scientist and engineer, I love this. 752 00:35:31,646 --> 00:35:35,116 I love that you name the age you live in by the material that 753 00:35:35,116 --> 00:35:36,284 mattered. 754 00:35:36,284 --> 00:35:41,155 But I also love that we will never do that again, ever. 755 00:35:41,155 --> 00:35:44,225 And the reason is that we live in a truly unique age now, 756 00:35:44,225 --> 00:35:47,962 a different age, one in which we can put atoms, 757 00:35:47,962 --> 00:35:52,200 we can realize Feynman's dream and put atoms anywhere we want. 758 00:35:52,200 --> 00:35:56,504 The question is not, can we make it as much 759 00:35:56,504 --> 00:35:59,240 any more as it is, what should we make? 760 00:35:59,240 --> 00:36:02,944 We live in the age of atomic design. 761 00:36:02,944 --> 00:36:04,178 And that is really important. 762 00:36:04,178 --> 00:36:08,182 And I mentioned the phone and the 63 elements. 763 00:36:08,182 --> 00:36:11,953 You know, look, this is called a revolution. 764 00:36:11,953 --> 00:36:14,956 This is called a revolution. 765 00:36:14,956 --> 00:36:19,060 You went in 50 years from $1 per transistor, 766 00:36:19,060 --> 00:36:22,029 eight orders of magnitude cheaper. 767 00:36:22,029 --> 00:36:26,534 In 2012, it became cheaper to print a transistor on a chip 768 00:36:26,534 --> 00:36:29,804 than a character in a newspaper. 769 00:36:29,804 --> 00:36:31,739 That's a revolution but that revolution, 770 00:36:31,739 --> 00:36:34,041 it started as a processing revolution 771 00:36:34,041 --> 00:36:37,044 with one really important element, silicon. 772 00:36:37,044 --> 00:36:41,849 And now it's a materials revolution, with 63. 773 00:36:41,849 --> 00:36:44,352 It's a chemistry revolution. 774 00:36:44,352 --> 00:36:48,222 And the reason this matters so much, what are these things, 775 00:36:48,222 --> 00:36:52,760 is because so many of the problems that we face 776 00:36:52,760 --> 00:36:56,664 in this world today, so many of the global challenges, 777 00:36:56,664 --> 00:37:02,036 will rely on new chemistry and on new materials. 778 00:37:02,036 --> 00:37:04,305 Those are the bottlenecks. 779 00:37:04,305 --> 00:37:06,407 Those are the bottlenecks in costs, in efficiency, 780 00:37:06,407 --> 00:37:09,336 in processing, in properties. 781 00:37:09,336 --> 00:37:10,711 And those are the kinds of things 782 00:37:10,711 --> 00:37:13,381 that we're going to be talking about all throughout the fall. 783 00:37:13,381 --> 00:37:16,384 And that is our construction set. 784 00:37:16,384 --> 00:37:19,820 And we will build this on Friday. 785 00:37:19,820 --> 00:37:21,622 So see you guys all on Friday. 786 00:37:21,622 --> 00:37:23,589 [INTERPOSING VOICES]