1 00:00:00,090 --> 00:00:02,490 The following content is provided under a Creative 2 00:00:02,490 --> 00:00:04,030 Commons license. 3 00:00:04,030 --> 00:00:06,330 Your support will help MIT OpenCourseWare 4 00:00:06,330 --> 00:00:10,720 continue to offer high-quality educational resources for free. 5 00:00:10,720 --> 00:00:13,320 To make a donation or view additional materials 6 00:00:13,320 --> 00:00:17,280 from hundreds of MIT courses, visit MIT OpenCourseWare 7 00:00:17,280 --> 00:00:18,450 at ocw.mit.edu. 8 00:00:21,960 --> 00:00:26,250 MARK HARTMAN: An observation is when you look at a model 9 00:00:26,250 --> 00:00:28,830 and you try to explain what you see in words. 10 00:00:28,830 --> 00:00:36,680 Whereas over here, I see a hypothesis based off 11 00:00:36,680 --> 00:00:39,560 of a model that can be used to compare 12 00:00:39,560 --> 00:00:42,410 to the actual tested experiment. 13 00:00:42,410 --> 00:00:46,104 So does the observation come from the model? 14 00:00:46,104 --> 00:00:47,520 Because that's what that's saying. 15 00:00:47,520 --> 00:00:49,430 Or does the prediction come from the model? 16 00:00:49,430 --> 00:00:51,320 Because that's what this is saying. 17 00:00:51,320 --> 00:00:55,310 You can't have it both ways, or can you? 18 00:00:55,310 --> 00:00:56,000 Let me think. 19 00:00:56,000 --> 00:00:59,200 What's the relationship between-- 20 00:00:59,200 --> 00:01:00,560 we're looking at models. 21 00:01:00,560 --> 00:01:05,736 What did we look at to get our predictions here in this case? 22 00:01:05,736 --> 00:01:07,252 AUDIENCE: The pictures. 23 00:01:07,252 --> 00:01:08,210 MARK HARTMAN: Go ahead. 24 00:01:08,210 --> 00:01:08,950 Say it nice and loud. 25 00:01:08,950 --> 00:01:09,860 We'll just have a conversation. 26 00:01:09,860 --> 00:01:11,340 You don't have to raise your hand. 27 00:01:11,340 --> 00:01:12,422 AUDIENCE: Pictures. 28 00:01:12,422 --> 00:01:13,130 MARK HARTMAN: OK. 29 00:01:13,130 --> 00:01:16,260 We looked at pictures to make predictions? 30 00:01:16,260 --> 00:01:16,945 AUDIENCE: Yes. 31 00:01:16,945 --> 00:01:17,820 MARK HARTMAN: Really? 32 00:01:17,820 --> 00:01:21,410 AUDIENCE: No, we used the model [INAUDIBLE] 33 00:01:21,410 --> 00:01:26,000 MARK HARTMAN: What did we look at to draw the prediction? 34 00:01:26,000 --> 00:01:28,339 Did you look at those to draw the prediction? 35 00:01:28,339 --> 00:01:28,880 AUDIENCE: No. 36 00:01:28,880 --> 00:01:30,590 MARK HARTMAN: No, you looked at this. 37 00:01:30,590 --> 00:01:33,620 You looked at the model to make the prediction. 38 00:01:33,620 --> 00:01:36,260 What did you look at to make the observation? 39 00:01:36,260 --> 00:01:37,556 AUDIENCE: The pictures. 40 00:01:37,556 --> 00:01:38,414 AUDIENCE: Pictures. 41 00:01:38,414 --> 00:01:39,830 MARK HARTMAN: The pictures, right? 42 00:01:39,830 --> 00:01:42,025 And what are those pictures of? 43 00:01:42,025 --> 00:01:42,858 AUDIENCE: The model. 44 00:01:42,858 --> 00:01:45,220 AUDIENCE: The [INAUDIBLE] model and the experiment. 45 00:01:45,220 --> 00:01:45,970 MARK HARTMAN: Ooh. 46 00:01:45,970 --> 00:01:46,840 Is that the model? 47 00:01:46,840 --> 00:01:47,610 Is that the experiment? 48 00:01:47,610 --> 00:01:48,401 Is it a hypothesis? 49 00:01:48,401 --> 00:01:49,450 Maybe it's a law. 50 00:01:49,450 --> 00:01:52,690 Let's just throw them all out, right? 51 00:01:52,690 --> 00:01:57,200 This, that thing up there, that picture is an observation, 52 00:01:57,200 --> 00:02:01,180 but it is an observation not of a model, but of reality. 53 00:02:06,760 --> 00:02:08,680 Yeah, that is a model. 54 00:02:08,680 --> 00:02:10,870 It's a kid's model that you put together. 55 00:02:10,870 --> 00:02:12,610 But that was a real thing. 56 00:02:12,610 --> 00:02:14,252 Somebody set that up in a photo studio, 57 00:02:14,252 --> 00:02:15,460 and they took pictures of it. 58 00:02:15,460 --> 00:02:17,290 That was a real thing. 59 00:02:17,290 --> 00:02:25,360 We were trying to get our model to represent that reality. 60 00:02:25,360 --> 00:02:29,230 So you've got reality that you look at 61 00:02:29,230 --> 00:02:31,020 and you make observations of. 62 00:02:31,020 --> 00:02:32,160 And I like this. 63 00:02:32,160 --> 00:02:34,900 "An observation is when you look at something"-- 64 00:02:34,900 --> 00:02:36,700 reality, the real thing-- 65 00:02:36,700 --> 00:02:40,120 "from one angle instead of looking at it from all angles." 66 00:02:40,120 --> 00:02:42,700 An observation, you can't capture the whole thing. 67 00:02:42,700 --> 00:02:45,040 You're only capturing part of it, whether that's-- 68 00:02:45,040 --> 00:02:48,460 if I wanted to make a measurement of the length 69 00:02:48,460 --> 00:02:50,770 of this thing, that's not the whole thing 70 00:02:50,770 --> 00:02:52,570 because I could also measure the mass. 71 00:02:52,570 --> 00:02:53,736 I could measure the density. 72 00:02:53,736 --> 00:02:55,420 I could look at the color. 73 00:02:55,420 --> 00:02:57,190 But it's when you look at something 74 00:02:57,190 --> 00:03:02,270 and you don't see it all, but you do see some of it. 75 00:03:02,270 --> 00:03:02,770 I like this. 76 00:03:02,770 --> 00:03:04,353 "Observation is looking at something." 77 00:03:04,353 --> 00:03:05,740 I think that's "looking," right? 78 00:03:05,740 --> 00:03:07,239 Observation is to look at something. 79 00:03:07,239 --> 00:03:08,940 AUDIENCE: Yeah. 80 00:03:08,940 --> 00:03:10,970 MARK HARTMAN: Now let's think about this. 81 00:03:10,970 --> 00:03:14,620 If we've got reality to this, "analyzing what we see in one 82 00:03:14,620 --> 00:03:18,100 image and putting them together to make a conclusion"-- uh-oh. 83 00:03:18,100 --> 00:03:19,765 Now we've got a conclusion in things. 84 00:03:24,480 --> 00:03:26,318 Where are our conclusions? 85 00:03:26,318 --> 00:03:28,760 AUDIENCE: At the end. 86 00:03:28,760 --> 00:03:30,090 MARK HARTMAN: At the end? 87 00:03:30,090 --> 00:03:33,480 What was our conclusion from this activity? 88 00:03:33,480 --> 00:03:34,845 AUDIENCE: Our predictions. 89 00:03:34,845 --> 00:03:36,720 MARK HARTMAN: Our predictions were the things 90 00:03:36,720 --> 00:03:38,260 that came out at the end. 91 00:03:38,260 --> 00:03:41,325 But what are we hoping about this model now? 92 00:03:41,325 --> 00:03:44,060 AUDIENCE: We can fix it [INAUDIBLE].. 93 00:03:44,060 --> 00:03:45,540 MARK HARTMAN: So that we can fix it 94 00:03:45,540 --> 00:03:48,300 based on the results of all those predictions 95 00:03:48,300 --> 00:03:52,380 that we then tested by looking at reality to figure out 96 00:03:52,380 --> 00:03:54,370 is this really right or not. 97 00:03:54,370 --> 00:03:56,640 Do we think that these models represent 98 00:03:56,640 --> 00:04:00,060 the reality of that situation pretty well now? 99 00:04:00,060 --> 00:04:01,082 AUDIENCE: Somewhat. 100 00:04:01,082 --> 00:04:02,040 MARK HARTMAN: Somewhat. 101 00:04:02,040 --> 00:04:03,456 I mean, we still had some problems 102 00:04:03,456 --> 00:04:06,870 with those last predictions, right? 103 00:04:06,870 --> 00:04:08,730 Now, if we went to this photo studio 104 00:04:08,730 --> 00:04:10,360 and actually looked at that object, 105 00:04:10,360 --> 00:04:12,360 it would be real easy to then, OK, well, let's 106 00:04:12,360 --> 00:04:13,770 take some measurements of it. 107 00:04:13,770 --> 00:04:17,500 Let's recreate this and measure the distance in between. 108 00:04:17,500 --> 00:04:18,510 But we can't do that. 109 00:04:18,510 --> 00:04:20,850 We only have these observations to go by. 110 00:04:23,460 --> 00:04:25,260 One other thing that I wanted to point out. 111 00:04:25,260 --> 00:04:29,580 So what is the thing that's related to the predictions? 112 00:04:29,580 --> 00:04:30,780 The model. 113 00:04:30,780 --> 00:04:32,370 From the model, you get predictions. 114 00:04:32,370 --> 00:04:34,870 From reality, you get the observation. 115 00:04:34,870 --> 00:04:37,140 Your ultimate goal is to try to get your model 116 00:04:37,140 --> 00:04:39,030 to be as much like reality as possible 117 00:04:39,030 --> 00:04:41,670 so that when you make predictions using the model, 118 00:04:41,670 --> 00:04:44,520 it makes sense. 119 00:04:44,520 --> 00:04:47,850 So let me-- one other thing that I really liked, 120 00:04:47,850 --> 00:04:51,820 because I really like this. 121 00:04:51,820 --> 00:04:55,100 Not that the others are bad or wrong, because they're there. 122 00:04:55,100 --> 00:04:58,590 "A model is an example that predicts observations 123 00:04:58,590 --> 00:05:02,220 in future instances." 124 00:05:02,220 --> 00:05:04,976 We predicted something that we hadn't quite looked at yet, 125 00:05:04,976 --> 00:05:06,600 and then we took another picture of it. 126 00:05:06,600 --> 00:05:08,580 And that made sense. 127 00:05:08,580 --> 00:05:10,780 Let me ask you one other question. 128 00:05:10,780 --> 00:05:13,020 Here, somebody wrote, "a prediction or hypothesis 129 00:05:13,020 --> 00:05:17,190 that can be proven as either true or false 130 00:05:17,190 --> 00:05:19,570 based on the facts of the experiment." 131 00:05:19,570 --> 00:05:22,990 And then over here, somebody said-- 132 00:05:22,990 --> 00:05:23,700 what was it? 133 00:05:29,600 --> 00:05:32,150 Well, let me put it to you this way. 134 00:05:32,150 --> 00:05:35,360 What do we prove? 135 00:05:35,360 --> 00:05:37,457 What are we trying to prove here? 136 00:05:37,457 --> 00:05:38,374 AUDIENCE: Predictions. 137 00:05:38,374 --> 00:05:40,081 MARK HARTMAN: We're trying to prove what? 138 00:05:40,081 --> 00:05:41,120 AUDIENCE: Predictions. 139 00:05:41,120 --> 00:05:43,535 MARK HARTMAN: We're trying to prove the predictions? 140 00:05:43,535 --> 00:05:46,395 AUDIENCE: We're trying to prove observations. 141 00:05:46,395 --> 00:05:49,071 MARK HARTMAN: We're trying to prove observations? 142 00:05:49,071 --> 00:05:50,922 AUDIENCE: That our model is right. 143 00:05:50,922 --> 00:05:52,380 MARK HARTMAN: We're trying to prove 144 00:05:52,380 --> 00:05:54,840 that our model is right, right? 145 00:05:54,840 --> 00:05:59,550 We are trying to prove that the predictions our model makes 146 00:05:59,550 --> 00:06:03,090 are actually correct, but that helps 147 00:06:03,090 --> 00:06:08,010 us to know that our model is a good representation of reality. 148 00:06:11,270 --> 00:06:13,402 So what I want to say to you, and I 149 00:06:13,402 --> 00:06:15,360 want you to discuss with the person next to you 150 00:06:15,360 --> 00:06:17,462 based on all of this stuff-- 151 00:06:17,462 --> 00:06:19,920 these ideas are still kind of floating around in our heads, 152 00:06:19,920 --> 00:06:20,970 and that's fine. 153 00:06:20,970 --> 00:06:24,100 And I want you to try and put those things together. 154 00:06:24,100 --> 00:06:27,699 But I do want to point out one other thing. 155 00:06:27,699 --> 00:06:29,490 "A model is a representation of the objects 156 00:06:29,490 --> 00:06:32,100 from the observations"-- so we went from the observations 157 00:06:32,100 --> 00:06:33,480 to the model-- 158 00:06:33,480 --> 00:06:36,360 "to make the big picture. 159 00:06:36,360 --> 00:06:37,370 What is the big picture? 160 00:06:39,980 --> 00:06:42,770 AUDIENCE: The actual model. 161 00:06:42,770 --> 00:06:46,010 MARK HARTMAN: The actual model, the whole thing, hopefully, 162 00:06:46,010 --> 00:06:48,030 that represents reality. 163 00:06:48,030 --> 00:06:51,700 So the big picture is the model. 164 00:06:51,700 --> 00:06:54,530 In going from the observation to the model, 165 00:06:54,530 --> 00:06:57,410 you could say, "analyzing what we see in one image." 166 00:06:57,410 --> 00:06:58,565 Stop there. 167 00:06:58,565 --> 00:07:02,270 The putting it together to then test it 168 00:07:02,270 --> 00:07:05,155 comes over here with the model. 169 00:07:05,155 --> 00:07:07,280 So what I want you to do is to talk with the person 170 00:07:07,280 --> 00:07:18,020 next to you about is it easier to prove 171 00:07:18,020 --> 00:07:27,550 a model correct or incorrect, and why? 172 00:07:27,550 --> 00:07:29,840 And we're going to kind of blend all these together. 173 00:07:29,840 --> 00:07:32,170 So I'm going to write a perspective 174 00:07:32,170 --> 00:07:34,510 that I think what each one of these things 175 00:07:34,510 --> 00:07:38,260 is, and we'll add that to our group dynamic. 176 00:07:38,260 --> 00:07:39,940 And we'll see, eventually, if we can 177 00:07:39,940 --> 00:07:42,170 kind of put all these together. 178 00:07:42,170 --> 00:07:47,970 So I'm going to say an observation is a description 179 00:07:47,970 --> 00:07:59,040 of what happens in a situation. 180 00:08:02,400 --> 00:08:04,820 And that situation is reality. 181 00:08:04,820 --> 00:08:06,940 So it's a description of what happens. 182 00:08:06,940 --> 00:08:10,840 The model, which, for us, we're going 183 00:08:10,840 --> 00:08:16,660 to say a model and a theory and an explanation-- 184 00:08:19,229 --> 00:08:20,770 we're going to say all those are kind 185 00:08:20,770 --> 00:08:25,210 of the same thing, the way that we use the word "model." 186 00:08:25,210 --> 00:08:29,400 And we are going to say that a model is an explanation. 187 00:08:33,549 --> 00:08:35,440 And that could be a 3D, physical model. 188 00:08:35,440 --> 00:08:37,480 That could be a mathematical representation. 189 00:08:37,480 --> 00:08:51,780 It is an explanation of why something happens or looks 190 00:08:51,780 --> 00:08:52,680 a particular way. 191 00:09:01,380 --> 00:09:03,650 So the observation is the what-- what happens, 192 00:09:03,650 --> 00:09:07,940 what does it look like, how big is it, how far away is it. 193 00:09:07,940 --> 00:09:12,030 The model is, why does it look like that in the first place? 194 00:09:12,030 --> 00:09:14,910 Because if we can understand that, 195 00:09:14,910 --> 00:09:17,420 then we really understand reality. 196 00:09:17,420 --> 00:09:26,560 And our testable prediction is a description 197 00:09:26,560 --> 00:09:44,835 of what will happen that you can then go observe. 198 00:09:48,440 --> 00:09:50,370 It's a prediction of what's going to happen. 199 00:09:50,370 --> 00:09:51,328 It hasn't happened yet. 200 00:09:51,328 --> 00:09:53,880 It's not an observation, but it's going to be. 201 00:09:53,880 --> 00:09:55,170 We can go look at it. 202 00:09:55,170 --> 00:09:57,270 That's why it's testable. 203 00:09:57,270 --> 00:09:59,950 If there was a non-testable observation-- 204 00:09:59,950 --> 00:10:03,810 like if I said, I think there's a small, tiny city of aliens 205 00:10:03,810 --> 00:10:07,500 that lives inside this block, you 206 00:10:07,500 --> 00:10:10,090 can't test that by taking pictures from the other side. 207 00:10:10,090 --> 00:10:11,730 Oh, but the aliens are inside. 208 00:10:11,730 --> 00:10:13,860 They don't come out. 209 00:10:13,860 --> 00:10:15,990 That's why there are people who think 210 00:10:15,990 --> 00:10:19,920 that sometimes in science, you can have all these crazy ideas. 211 00:10:19,920 --> 00:10:22,740 But if there's no way to test them, all you're doing 212 00:10:22,740 --> 00:10:23,670 is making things up. 213 00:10:27,360 --> 00:10:31,620 However, if I could chop that block in half and look, 214 00:10:31,620 --> 00:10:35,400 then I might be able to see the little aliens. 215 00:10:35,400 --> 00:10:37,620 So a testable prediction is a description 216 00:10:37,620 --> 00:10:39,600 of what will happen. 217 00:10:39,600 --> 00:10:41,790 And I always throw this in because everybody always 218 00:10:41,790 --> 00:10:45,200 asks, well, what's a law, then? 219 00:10:45,200 --> 00:10:47,220 Because what do you think a law is? 220 00:10:50,646 --> 00:10:52,812 AUDIENCE: A prediction that has been proven as fact. 221 00:10:52,812 --> 00:10:54,220 MARK HARTMAN: Say that again, nice and loud. 222 00:10:54,220 --> 00:10:56,303 AUDIENCE: A prediction that's been proven as fact. 223 00:10:56,303 --> 00:10:57,727 MARK HARTMAN: Oh, you're wrong. 224 00:10:57,727 --> 00:10:58,560 AUDIENCE: I'm wrong? 225 00:10:58,560 --> 00:10:59,150 MARK HARTMAN: This is-- 226 00:10:59,150 --> 00:11:01,150 no, I don't mean to pick on you, [INAUDIBLE].. 227 00:11:01,150 --> 00:11:06,580 But a law is not a model or a theory that stands up. 228 00:11:06,580 --> 00:11:07,840 You can throw stuff at it. 229 00:11:07,840 --> 00:11:09,910 Man, it's always right. 230 00:11:09,910 --> 00:11:11,860 They're two fundamentally different things. 231 00:11:11,860 --> 00:11:14,320 A model or a theory is an explanation 232 00:11:14,320 --> 00:11:16,270 of why something happens. 233 00:11:16,270 --> 00:11:20,170 A law-- like, if you think about the law of gravity, 234 00:11:20,170 --> 00:11:22,420 things always fall down. 235 00:11:22,420 --> 00:11:25,090 That's an easy way to say it. 236 00:11:25,090 --> 00:11:32,000 We still have no idea why things are attracted to other things, 237 00:11:32,000 --> 00:11:35,770 but we can say that it always happens that way. 238 00:11:35,770 --> 00:11:54,780 So a law is a statement of what always happens in a situation. 239 00:11:57,757 --> 00:11:59,590 And you'll notice the fundamental difference 240 00:11:59,590 --> 00:12:04,360 between a law and a theory is that this theory 241 00:12:04,360 --> 00:12:06,000 deals with why. 242 00:12:06,000 --> 00:12:07,340 A law doesn't deal with why. 243 00:12:07,340 --> 00:12:11,060 A law is just a statement of, this is always going to happen. 244 00:12:11,060 --> 00:12:13,165 It doesn't say why. 245 00:12:13,165 --> 00:12:19,070 It does not say why. 246 00:12:19,070 --> 00:12:20,920 So think about that.