1 00:00:00,030 --> 00:00:02,400 The following content is provided under a Creative 2 00:00:02,400 --> 00:00:03,840 Commons license. 3 00:00:03,840 --> 00:00:06,850 Your support will help MIT Open CourseWare continue to 4 00:00:06,850 --> 00:00:10,520 offer high-quality educational resources for free. 5 00:00:10,520 --> 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 00:00:24,440 --> 00:00:27,940 We, we are solid state devices. 9 00:00:27,940 --> 00:00:29,710 This is soft matter. 10 00:00:29,710 --> 00:00:32,210 My eyes are photo detectors. 11 00:00:32,210 --> 00:00:34,260 Band gap of about two electron volts. 12 00:00:34,260 --> 00:00:35,610 They're just not made of a compound 13 00:00:35,610 --> 00:00:38,200 semiconductor inorganic. 14 00:00:38,200 --> 00:00:40,530 And this motion is just conformational 15 00:00:40,530 --> 00:00:42,860 changes in a polymer. 16 00:00:42,860 --> 00:00:44,850 See it's all chemistry. 17 00:00:44,850 --> 00:00:46,496 The rest is stamp collecting. 18 00:00:50,390 --> 00:00:56,680 So the principles that apply to inanimate objects apply to 19 00:00:56,680 --> 00:00:57,700 animate objects. 20 00:00:57,700 --> 00:01:03,820 And the solid-state chemistry umbrella is very broad. 21 00:01:03,820 --> 00:01:06,990 If I say solid-state chemistry, people are apt to 22 00:01:06,990 --> 00:01:12,120 think of electronic devices, transistors, what have you. 23 00:01:12,120 --> 00:01:14,400 But that extends to the life sciences. 24 00:01:14,400 --> 00:01:18,430 I mean we, as human beings, are chemical machines. 25 00:01:18,430 --> 00:01:20,450 So this is the classical view. 26 00:01:20,450 --> 00:01:23,740 Electronic structuring informs bonding but then in 3.091 27 00:01:23,740 --> 00:01:26,170 bonding informs atomic arrangement, which tells you 28 00:01:26,170 --> 00:01:28,560 everything. 29 00:01:28,560 --> 00:01:32,380 The shape of all things, it's all electronic structure. 30 00:01:32,380 --> 00:01:34,220 There's nothing more. 31 00:01:34,220 --> 00:01:37,730 The difference is that the focus in the chemistry 32 00:01:37,730 --> 00:01:42,710 department, their focus is the molecule. 33 00:01:42,710 --> 00:01:47,930 Whereas in 3.091 I like to think of the focus being 34 00:01:47,930 --> 00:01:50,950 aggregates of molecules, namely solids. 35 00:01:50,950 --> 00:01:53,625 Because engineering systems are made of solids. 36 00:01:58,390 --> 00:02:00,540 If you're steeped in chemistry from high school, you've had 37 00:02:00,540 --> 00:02:06,530 the AP curriculum, again 3.091 might be something that is a 38 00:02:06,530 --> 00:02:09,380 fresh look at chemistry from a slightly different 39 00:02:09,380 --> 00:02:10,480 perspective. 40 00:02:10,480 --> 00:02:13,700 What I wanted to play for you as you're leaving today is an 41 00:02:13,700 --> 00:02:16,810 old Beatles song, Lucy in the Sky with Diamonds. 42 00:02:16,810 --> 00:02:21,240 Being able to bring in subject matter, music, art, 43 00:02:21,240 --> 00:02:25,570 literature, into a chemistry class and make the connections 44 00:02:25,570 --> 00:02:28,990 to the world around us, I think is most important in the 45 00:02:28,990 --> 00:02:32,660 21st century, when problem solving even in the technical 46 00:02:32,660 --> 00:02:37,570 domain is going to require skills that build bridges to 47 00:02:37,570 --> 00:02:40,050 the humanities, arts and social sciences. 48 00:02:40,050 --> 00:02:45,060 And so I like to think of 3.091 not as a chemistry 49 00:02:45,060 --> 00:02:47,800 class, but rather a chemistry-centered class. 50 00:02:52,450 --> 00:02:57,570 The majority of students taking 3.091 at MIT may never 51 00:02:57,570 --> 00:02:59,840 take another chemistry class. 52 00:02:59,840 --> 00:03:04,880 So I ask myself what topics are critical for someone who 53 00:03:04,880 --> 00:03:08,490 might major in electrical engineering? 54 00:03:08,490 --> 00:03:11,330 Or for someone who might major in physics? 55 00:03:11,330 --> 00:03:15,325 Or what's the chemistry that's critical to an MIT student who 56 00:03:15,325 --> 00:03:18,840 might major in political science or economics? 57 00:03:18,840 --> 00:03:23,980 And that informs my choice of topics. 58 00:03:23,980 --> 00:03:29,640 And it turns out that that doesn't diminish from the 59 00:03:29,640 --> 00:03:33,300 education of the student who may choose to major in a 60 00:03:33,300 --> 00:03:36,370 chemically intensive discipline such as material 61 00:03:36,370 --> 00:03:40,110 science, chemical engineering, or even chemistry itself. 62 00:03:40,110 --> 00:03:46,080 I don't view the presentation of the subject matter as a 63 00:03:46,080 --> 00:03:48,760 linear track, where this is the beginning 64 00:03:48,760 --> 00:03:49,810 and this is the end. 65 00:03:49,810 --> 00:03:53,110 I view it more along the lines of a spiral. 66 00:03:53,110 --> 00:03:56,640 And so the first time you encounter a certain concept 67 00:03:56,640 --> 00:04:02,090 it's at a rather superficial introductory level. 68 00:04:02,090 --> 00:04:05,540 And then at some point later in the semester you spiral 69 00:04:05,540 --> 00:04:06,750 back and see it again. 70 00:04:06,750 --> 00:04:09,240 And then maybe there's a little more context and a 71 00:04:09,240 --> 00:04:10,290 little more intensity. 72 00:04:10,290 --> 00:04:13,980 Maybe there's a little more mathematics 73 00:04:13,980 --> 00:04:15,040 associated with it. 74 00:04:15,040 --> 00:04:18,540 And then you'll see it applied later again. 75 00:04:18,540 --> 00:04:21,570 And through that revisiting-- 76 00:04:21,570 --> 00:04:23,770 repetition by design-- 77 00:04:23,770 --> 00:04:27,760 I think that key concepts get driven home. 78 00:04:32,160 --> 00:04:36,350 Some people are shocked that I stand in front of a chalk 79 00:04:36,350 --> 00:04:40,270 board and I write on it and I believe that that's still a 80 00:04:40,270 --> 00:04:42,940 valid means of teaching. 81 00:04:42,940 --> 00:04:45,190 For the first-time learner I think it's important to 82 00:04:45,190 --> 00:04:47,970 activate all of the learning channels. 83 00:04:47,970 --> 00:04:51,260 The act of drawing and inspiring 84 00:04:51,260 --> 00:04:53,450 them to draw is important. 85 00:04:53,450 --> 00:04:57,130 And maybe the person at home ought to put themselves in a 86 00:04:57,130 --> 00:05:00,970 chair in the auditorium and be taking notes as though they 87 00:05:00,970 --> 00:05:03,150 are attending the lecture. 88 00:05:03,150 --> 00:05:05,445 Watching those videos, especially for someone that 89 00:05:05,445 --> 00:05:08,290 has had a fair bit of high school chemistry, you're going 90 00:05:08,290 --> 00:05:14,150 to hear a lot of the same things but maybe coming at you 91 00:05:14,150 --> 00:05:16,840 at a slightly elevated level. 92 00:05:16,840 --> 00:05:19,870 But not so elevated that you won't follow it. 93 00:05:19,870 --> 00:05:23,110 And I think that's good for a high school student to be 94 00:05:23,110 --> 00:05:25,320 talked to at a higher level. 95 00:05:25,320 --> 00:05:28,850 I think the videos also have utility for people that are 96 00:05:28,850 --> 00:05:30,550 interested in specific topics. 97 00:05:30,550 --> 00:05:33,080 I mean for example, if somebody needs to know 98 00:05:33,080 --> 00:05:38,650 something about x-rays, or the use of x-rays, dropping in to 99 00:05:38,650 --> 00:05:46,250 that three-lecture sequence on x-rays could be quite useful. 100 00:05:46,250 --> 00:05:51,430 I think it's possible to sample with a goal of 101 00:05:51,430 --> 00:05:55,690 mastering a particular concept. 102 00:05:55,690 --> 00:06:03,250 So clearly for the learner out in the World Wide Web, going 103 00:06:03,250 --> 00:06:07,670 to recitation and interacting with a recitation instructor 104 00:06:07,670 --> 00:06:08,840 is not practical. 105 00:06:08,840 --> 00:06:15,120 So in lieu of the recitation section OCW has created these 106 00:06:15,120 --> 00:06:16,860 help session videos. 107 00:06:16,860 --> 00:06:21,930 We actually hired some recitation instructors from 108 00:06:21,930 --> 00:06:26,100 the fall of 2009 and asked them to work through some 109 00:06:26,100 --> 00:06:29,990 sample problems and what you see in the help session video 110 00:06:29,990 --> 00:06:31,780 is essentially what would have happened in 111 00:06:31,780 --> 00:06:33,980 a recitation section. 112 00:06:33,980 --> 00:06:38,500 I issue the homework questions with model solutions at the 113 00:06:38,500 --> 00:06:39,315 beginning of the unit. 114 00:06:39,315 --> 00:06:43,710 So the homework becomes a study aid. 115 00:06:43,710 --> 00:06:48,270 And I recommend to students that they try the homework 116 00:06:48,270 --> 00:06:54,470 problems without referring to the answer key initially. 117 00:06:54,470 --> 00:06:59,870 And to turn to the answer key when they reach an impediment. 118 00:07:04,770 --> 00:07:11,080 What's the message of 3.091 for the man on the street? 119 00:07:11,080 --> 00:07:14,000 An understanding of those relationships. 120 00:07:14,000 --> 00:07:15,820 Electronic structure to bonding. 121 00:07:15,820 --> 00:07:17,480 Bonding to atomic arrangement. 122 00:07:17,480 --> 00:07:19,930 Atomic arrangement to properties. 123 00:07:19,930 --> 00:07:24,150 Is the key to understanding the world around us. 124 00:07:24,150 --> 00:07:30,100 And in particular it's the key to fueling invention. 125 00:07:30,100 --> 00:07:35,390 And I believe in practice very much and in the application of 126 00:07:35,390 --> 00:07:39,730 science in service for humanity. 127 00:07:39,730 --> 00:07:43,230 Why do we worry about designing a car that's a 128 00:07:43,230 --> 00:07:46,200 zero-emission vehicle, as if to do no harm to the 129 00:07:46,200 --> 00:07:47,110 environment? 130 00:07:47,110 --> 00:07:50,310 Why don't we go even further and say, what about a car that 131 00:07:50,310 --> 00:07:52,540 purifies the air as it drives down the road? 132 00:07:52,540 --> 00:07:55,740 So that the air in the wake of the car is cleaner than the 133 00:07:55,740 --> 00:07:58,060 air in front of the car? 134 00:07:58,060 --> 00:08:01,290 And I'm finding that increasingly that's a message 135 00:08:01,290 --> 00:08:03,630 that resonates with the students. 136 00:08:03,630 --> 00:08:09,340 They want to take the tools of technical analytically 137 00:08:09,340 --> 00:08:12,070 centered education and put them to work to 138 00:08:12,070 --> 00:08:15,350 solve societal problems.