1 00:00:05,580 --> 00:00:09,630 YEN-JIE LEE: Before people take 8.03 class, especially 2 00:00:09,630 --> 00:00:12,810 my version, most of the students may 3 00:00:12,810 --> 00:00:18,930 think uncertainty principle is actually completely related 4 00:00:18,930 --> 00:00:20,980 to quantum mechanics. 5 00:00:20,980 --> 00:00:23,520 So actually it is actually not the case. 6 00:00:23,520 --> 00:00:27,180 Actually, uncertainty principle almost have nothing 7 00:00:27,180 --> 00:00:29,770 to do with quantum mechanics. 8 00:00:29,770 --> 00:00:35,370 It has to do with just the wave description we employ 9 00:00:35,370 --> 00:00:37,680 when we describe the system. 10 00:00:37,680 --> 00:00:39,390 So that's actually one of the big thing 11 00:00:39,390 --> 00:00:42,960 which you will learn from 8.03. 12 00:00:42,960 --> 00:00:48,420 The other thing which people will learn a lot more 13 00:00:48,420 --> 00:00:52,780 is actually that before they come into the class, 14 00:00:52,780 --> 00:00:57,450 they may think it's almost impossible to understand 15 00:00:57,450 --> 00:01:00,300 infinitely number of coupled oscillators. 16 00:01:00,300 --> 00:01:05,280 And it turns out that there is a very systematical way 17 00:01:05,280 --> 00:01:10,500 you can actually make use of simple symmetry argument, 18 00:01:10,500 --> 00:01:13,410 and that you can actually greatly simplify 19 00:01:13,410 --> 00:01:18,000 complicated system, like infinity long system. 20 00:01:18,000 --> 00:01:20,870 So it is actually not an impossible task, 21 00:01:20,870 --> 00:01:23,600 and then everything can be actually understand, 22 00:01:23,600 --> 00:01:29,270 using the concept of symmetry, which we introduce in 8.03.