1 00:00:06,280 --> 00:00:08,870 YEN-JIE LEE: I decided to include a lot of demos 2 00:00:08,870 --> 00:00:11,110 during my lectures. 3 00:00:11,110 --> 00:00:15,730 That is because I believe to learn physics, 4 00:00:15,730 --> 00:00:20,650 you have to know how to convert everything into mathematics. 5 00:00:20,650 --> 00:00:23,620 You want to work on the mathematics 6 00:00:23,620 --> 00:00:26,290 and to make predictions, and finally, you 7 00:00:26,290 --> 00:00:31,240 want to compare the predictions to experimental data. 8 00:00:31,240 --> 00:00:34,090 Demonstrations are particularly useful because I 9 00:00:34,090 --> 00:00:37,480 would like to show that the mathematics we 10 00:00:37,480 --> 00:00:41,590 covered during the classroom actually 11 00:00:41,590 --> 00:00:43,570 have a lot of consequence. 12 00:00:43,570 --> 00:00:46,900 It's actually really to do with what 13 00:00:46,900 --> 00:00:51,390 nature does to all the physical systems we are interested. 14 00:00:51,390 --> 00:00:54,140 So that's actually why we first-- 15 00:00:54,140 --> 00:00:56,090 usually the structure is like this. 16 00:00:56,090 --> 00:00:59,110 We first introduce the physical situation 17 00:00:59,110 --> 00:01:03,310 we are interested then we use the concepts 18 00:01:03,310 --> 00:01:07,280 and the mathematics to solve the physical system, 19 00:01:07,280 --> 00:01:11,110 and finally, the last part is to enjoy what we have 20 00:01:11,110 --> 00:01:14,170 learned from this hard work. 21 00:01:14,170 --> 00:01:20,180 To compare our mathematical solution to reality, 22 00:01:20,180 --> 00:01:21,910 which is actually the demo. 23 00:01:21,910 --> 00:01:28,180 So that is actually why I introduce so many demos 24 00:01:28,180 --> 00:01:31,370 during the class, and those, I do think, 25 00:01:31,370 --> 00:01:35,620 using those demos people will remember more 26 00:01:35,620 --> 00:01:38,080 about the conclusion we can actually 27 00:01:38,080 --> 00:01:41,080 get from the mathematics instead of 28 00:01:41,080 --> 00:01:44,740 overwhelmed by a lot of calculations during the class. 29 00:01:52,420 --> 00:01:57,550 There are so many interesting demos which we covered. 30 00:01:57,550 --> 00:02:03,810 One of my favorite demos is the Bell wave machine. 31 00:02:03,810 --> 00:02:07,670 First of all, it's really a very beautiful demo. 32 00:02:07,670 --> 00:02:12,060 It is so beautiful to see the sinusoidal wave. 33 00:02:12,060 --> 00:02:17,470 It can be produced from this simple device. 34 00:02:17,470 --> 00:02:19,960 Secondly, you you can actually manipulate them, 35 00:02:19,960 --> 00:02:22,540 you can connect them to each other, 36 00:02:22,540 --> 00:02:25,420 and you can see waves essentially bouncing 37 00:02:25,420 --> 00:02:29,170 between systems, and then you can see the reflection 38 00:02:29,170 --> 00:02:30,700 of the traveling wave. 39 00:02:30,700 --> 00:02:34,020 It's so beautiful, and that's actually my favorite demo 40 00:02:34,020 --> 00:02:34,990 during the class. 41 00:02:34,990 --> 00:02:38,740 I believe most of the students are also 42 00:02:38,740 --> 00:02:42,180 interested in that demo very, very much.