The call to learn | Clifford Stoll

1,287,437 views ・ 2008-03-27

TED


请双击下面的英文字幕来播放视频。

翻译人员: Yuan Huang 校对人员: zhangb bin
00:12
I'm delighted to be here.
0
12160
2000
很高兴来到这里。
00:14
I'm honored by the invitation, and thanks.
1
14160
3000
收到这份邀请使我感到非常荣幸,谢谢。
00:17
I would love to talk about stuff that I'm interested in,
2
17160
3000
我很高兴能够讲述我感兴趣的东西,
00:20
but unfortunately, I suspect that what I'm interested in
3
20160
2000
遗憾的是我估计,我感兴趣的东西
00:22
won't interest many other people.
4
22160
3000
绝大多数人会不感兴趣。
00:25
First off, my badge says I'm an astronomer.
5
25160
2000
首先,我的正式职业是一名天文学家。
00:27
I would love to talk about my astronomy,
6
27160
2000
我很想谈谈我对天文学的研究,
00:29
but I suspect that the number of people who are interested in radiative transfer
7
29160
3000
但我怀疑对辐射转移
00:32
in non-gray atmospheres
8
32160
2000
对非灰色大气层
00:34
and polarization of light in Jupiter's upper atmosphere
9
34160
2000
以及对木星的高层大气的光偏振
00:36
are the number of people who'd fit in a bus shelter.
10
36160
2000
感兴趣的人加起来是否能挤得满一个公共汽车候车亭。
00:38
So I'm not going to talk about that.
11
38160
2000
所以我不打算去谈论它。
00:40
(Laughter)
12
40160
2000
(众笑)
00:42
It would be just as much fun
13
42160
2000
另外一件值得一谈的趣事
00:44
to talk about some stuff that happened in 1986 and 1987,
14
44160
3000
发生在1986年和1987年,
00:47
when a computer hacker is breaking into our systems
15
47160
3000
当时一个电脑黑客想要进入
00:50
over at Lawrence Berkeley Labs.
16
50160
2000
我们在Lawrence Berkeley研究所的系统。
00:52
And I caught the guys,
17
52160
2000
我抓到了那些黑客,
00:54
and they turned out to be working for what was then the Soviet KGB,
18
54160
4000
并且发现他们当时正在为前苏联克格勃工作,
00:58
and stealing information and selling it.
19
58160
2000
他们想要窃取我们的信息并且倒卖出去。
01:00
And I'd love to talk about that -- and it'd be fun --
20
60160
4000
我很想谈谈这件事情─而且一定会很有趣─
01:04
but, 20 years later ...
21
64160
3000
但是20年以后…
01:07
I find computer security, frankly, to be kind of boring.
22
67160
2000
我发现电脑安全这个领域,说老实话,有点无聊。
01:09
It's tedious.
23
69160
2000
它过于乏味。
01:11
I'm --
24
71160
1000
我…
01:12
The first time you do something, it's science.
25
72160
3000
当你第一次做一件事情的时候,就像搞科研。
01:16
The second time, it's engineering.
26
76160
3000
第二次做这件事情,就像搞工程。
01:19
A third time, it's just being a technician.
27
79160
3000
第三次,就像成了一个技师。
01:22
I'm a scientist. Once I do something, I do something else.
28
82160
3000
我是一个科学家。当我在着手一件事情的时候,我已经开始想着下一件事情了。
01:25
So, I'm not going to talk about that.
29
85160
2000
所以我也不会讲那个黑客的故事。
01:27
Nor am I going to talk about what I think are obvious statements from my first book,
30
87160
7000
我也不会去谈那些我认为我的第一本书(Silicon Snake Oil)里很明确的观点,
01:34
"Silicon Snake Oil," or my second book,
31
94160
3000
我也不会去谈论我的第二本书,
01:38
nor am I going to talk about
32
98160
2000
我更不会去谈论
01:40
why I believe computers don't belong in schools.
33
100160
2000
为什么我认为电脑不应当进入学校。
01:43
I feel that there's a massive and bizarre idea going around
34
103160
4000
现在有一个影响力很大的奇怪的提议
01:47
that we have to bring more computers into schools.
35
107160
4000
就是要在学校普及电脑。
01:51
My idea is: no! No!
36
111160
2000
我的观点是:万万不可!
01:53
Get them out of schools, and keep them out of schools.
37
113160
4000
让电脑远离学校,永远不许电脑进入学校的大门。
01:57
And I'd love to talk about this,
38
117160
2000
这也是一个我想要谈论的问题。
01:59
but I think the argument is so obvious to anyone who's hung around a fourth grade classroom
39
119160
5000
但我认为我的理由对于任何一个在四年级教室里待过的人是如此的明显,
02:04
that it doesn't need much talking about --
40
124160
4000
以至于没有必要再在这里谈了─
02:08
but I guess I may be very wrong about that,
41
128160
2000
但我的观点可能是相当错误的,
02:10
and everything else that I've said.
42
130160
1000
包括我刚刚说的所有东西都可能是错误的。
02:11
So don't go back and read my dissertation.
43
131160
2000
所以不必回头再去评判我的论点。
02:13
It probably has lies in it as well.
44
133160
2000
甚至可能在这里我说的也不是真话。
02:15
Having said that, I outlined my talk about five minutes ago.
45
135160
4000
说到这里,五分钟前我把我的演讲列了一个提纲。
02:19
(Laughter)
46
139160
3000
(众笑)
02:22
And if you look at it over here,
47
142160
2000
假如你看这里,
02:24
the main thing I wrote on my thumb was the future.
48
144160
3000
写在我大拇指上的最主要的东西是未来。
02:27
I'm supposed to talk about the future, yes?
49
147160
3000
我是不是应该讨论一下未来?
02:30
Oh, right. And my feeling is, asking me to talk about the future is bizarre,
50
150160
7000
噢,对了。我的感觉是,让我讨论未来是一件很奇怪的是,
02:37
because I've got gray hair,
51
157160
2000
因为我已经满头灰白了,
02:39
and so, it's kind of silly for me to talk about the future.
52
159160
6000
所以让我去讨论未来有些愚蠢。
02:45
In fact, I think that if you really want to know what the future's going to be,
53
165160
4000
事实上,我认为假如你真的要知道未来是什么样子的,
02:49
if you really want to know about the future,
54
169160
2000
假如你真的想要知道未来,
02:51
don't ask a technologist, a scientist, a physicist.
55
171160
4000
不要去问科技专家,科学家,或者物理学家
02:55
No! Don't ask somebody who's writing code.
56
175160
4000
千万不要问那些写程序的人。
03:02
No, if you want to know what society's going to be like in 20 years,
57
182160
5000
如果你想要知道这个社会20年后会是什么样儿,
03:07
ask a kindergarten teacher.
58
187160
2000
去问一个幼儿园教师。
03:09
They know.
59
189160
3000
他们知道。
03:12
In fact, don't ask just any kindergarten teacher,
60
192160
3000
当然,也不要随便逮着一个幼儿园教师就问,
03:15
ask an experienced one.
61
195160
2000
要去问有经验的。
03:17
They're the ones who know what society is going to be like in another generation.
62
197160
4000
他们就是那些知道下一代社会会是什么样儿的人。
03:21
I don't. Nor, I suspect,
63
201160
2000
不光是我,
03:23
do many other people who are talking about what the future will bring.
64
203160
3000
许多在谈论未来是什么样子的人其实并不知道未来是什么样子的。
03:26
Certainly, all of us can imagine these cool new things
65
206160
4000
当然了,谁都可以想象将可能出现的
03:30
that are going to be there.
66
210160
1000
那些新奇好玩的新事物。
03:31
But to me, things aren't the future.
67
211160
4000
但是对我来说,新鲜事物不代表未来。
03:35
What I ask myself is, what's society is going to be like,
68
215160
3000
我认为真正重要的是,未来的社会将是什么样的,
03:38
when the kids today are phenomenally good at text messaging
69
218160
6000
当今天的孩子如此熟练的发短信,
03:44
and spend a huge amount of on-screen time,
70
224160
3000
并且花费相当多的时间在电子屏幕前,
03:47
but have never gone bowling together?
71
227160
5000
却从来没有一起去打过保龄球。
03:53
Change is happening, and the change that is happening
72
233160
3000
变化正在发生,而且那些在发生的变化
03:56
is not one that is in software.
73
236160
2000
并非是发生在软件里的变化。
03:59
But that's not what I'm going to talk about.
74
239160
1000
但这不是是我将要谈论到的。
04:00
I'd love to talk about it, it'd be fun,
75
240160
3000
我很想谈谈这个话题,那一定会很有趣,
04:03
but I want to talk about what I'm doing now. What am I doing now?
76
243160
3000
但是我想要谈谈我最近在干的一些事情。我现在正在干什么?
04:06
Oh -- the other thing that I think I'd like to talk about
77
246160
2000
噢─我另外想提到的一些事情
04:08
is right over here. Right over here.
78
248160
3000
就是这个
04:12
Is that visible? What I'd like to talk about is one-sided things.
79
252160
6000
你们看得见吗?我想说的叫单向性事物。
04:18
I would dearly love to talk about
80
258160
2000
我非常乐于谈谈
04:20
things that have one side.
81
260160
3000
这种单向性事物。
04:23
Because I love Mobius loops. I not only love Mobius loops,
82
263160
4000
因为我一直迷恋莫比乌斯带。不只是莫比乌斯带,
04:27
but I'm one of the very few people,
83
267160
3000
我还是世界上独一无二
04:30
if not the only person in the world, that makes Klein bottles.
84
270160
3000
的制造克莱因瓶的人,
04:33
Right away, I hope that all of your eyes glaze over.
85
273160
3000
好了,我希望你们好好地盯着这个瓶子。
04:36
This is a Klein bottle.
86
276160
3000
这是一个克莱因瓶。
04:39
For those of you in the audience who know,
87
279160
3000
对于你们当中一些知道什么叫克莱因瓶的人来说,
04:42
you roll your eyes and say, yup, I know all about it.
88
282160
2000
你肯定会转一转你的眼睛,然后说,是的,我知道这是怎么一回事。
04:44
It's one sided. It's a bottle whose inside is its outside.
89
284160
2000
这个瓶子的内壁和外壁其实是同一个面。
04:46
It has zero volume. And it's non-orientable.
90
286160
3000
这个瓶子的容积为零。而且是无定向性的。
04:49
It has wonderful properties.
91
289160
2000
它具有非常奇妙的特性。
04:51
If you take two Mobius loops and sew their common edge together,
92
291160
2000
假如你将两个莫比乌斯带的相同边缘缝接起来,
04:53
you get one of these, and I make them out of glass.
93
293160
3000
你就会得到我手里一样的东西,它是用玻璃制造的。
04:56
And I'd love to talk to you about this,
94
296160
2000
我很乐意跟你们谈谈这个东西,
04:58
but I don't have much in the way of ... things to say because --
95
298160
4000
但是我又没什么可多说的,因为─
05:04
(Laughter)
96
304160
2000
(众笑)
05:06
(Chris Anderson: I've got a cold.)
97
306160
1000
(Chris Anderson: 我有感冒。)
05:07
However, the "D" in TED of course stands for design.
98
307160
7000
然而,“TED”中的“D”代表的是设计(design)
05:14
Just two weeks ago I made --
99
314160
2000
两周前我刚刚做了─
05:16
you know, I've been making small, medium and big Klein bottles for the trade.
100
316160
6000
事实上,我一直在制造并且买卖小,中,和大型克莱因瓶。
05:22
But what I've just made --
101
322160
4000
但是我刚刚做了一个─
05:26
and I'm delighted to show you, first time in public here.
102
326160
3000
我很高兴能够第一次在公共场合下展示给你们看。
05:35
This is a Klein bottle wine bottle,
103
335160
5000
这是一个克莱因葡萄酒瓶,
05:40
which, although in four dimensions
104
340160
3000
尽管在一个具有四维空间的
05:43
it shouldn't be able to hold any fluid at all,
105
343160
3000
瓶子里储存不了任何液体,
05:46
it's perfectly capable of doing so
106
346160
2000
但是这个瓶子却完全可以。
05:48
because our universe has only three spatial dimensions.
107
348160
2000
因为我们所处的宇宙只有三维。
05:50
And because our universe is only three spatial dimensions,
108
350160
3000
正是因为这个宇宙只有三维空间,
05:53
it can hold fluids.
109
353160
2000
所以这个瓶子可以储存液体。
05:56
So it's highly -- that one's the cool one.
110
356160
5000
所以它很─ 这是比较酷的一个。
06:01
That was a month of my life.
111
361160
5000
它花费了我一个月的时间。
06:06
But although I would love to talk about topology with you, I'm not going to.
112
366160
4000
虽然我很乐意跟你们解释拓扑学,但是今天我不会。
06:11
(Laughter)
113
371160
6000
(众笑)
06:17
Instead, I'm going to mention my mom,
114
377160
5000
相反,我想说一下我的母亲,
06:22
who passed away last summer.
115
382160
3000
她去年夏天过世了。
06:25
Had collected photographs of me, as mothers will do.
116
385160
3000
她生前保存了很多我的照片,就像所有的母亲一样。
06:28
Could somebody put this guy up?
117
388160
2000
你们谁可以把屏幕信号切到这个幻灯?
06:30
And I looked over her album
118
390160
4000
当我看她的相册时
06:34
and she had collected a picture of me, standing --
119
394160
3000
她有这样一张关于我的照片,站着─
06:37
well, sitting -- in 1969, in front of a bunch of dials.
120
397160
4000
哦不对,坐着,那是1969年,我的背后是一片旋钮。
06:42
And I looked at it, and said, oh my god,
121
402160
3000
我看着这张照片,我说,天哪,
06:45
that was me, when I was working at the electronic music studio!
122
405160
2000
那是我还在电子音乐工作室的时候的照片!
06:47
As a technician, repairing and maintaining
123
407160
3000
作为一个技工,负责对仪器的维修和保养
06:51
the electronic music studio at SUNY Buffalo. And wow!
124
411160
4000
那个工作室在纽约州立大学水牛城分校。天哪!
06:55
Way back machine. And I said to myself, oh yeah!
125
415160
5000
很陈旧的设备。然后我对自己说,噢,我想起来了!
07:01
And it sent me back.
126
421160
2000
这张照片将我的思绪送回了过去。
07:05
Soon after that, I found in another picture that she had, a picture of me.
127
425160
7000
不久以后,我找到了另外一张我妈妈替我保存的我的照片。
07:13
This guy over here of course is me.
128
433160
4000
这个家伙显然就是我。
07:17
This man is Robert Moog,
129
437160
2000
这个人是Robert Moog,
07:19
the inventor of the Moog synthesizer,
130
439160
2000
Moog合成器的发明者,
07:21
who passed away this past August.
131
441160
4000
他去年八月份过世了。
07:26
Robert Moog was a generous, kind person, extraordinarily competent engineer.
132
446160
5000
Robert Moog是一个心胸宽广,温和善良的人;他同时又是一个才华横溢的工程师。
07:31
A musician who took time from his life to teach me,
133
451160
4000
他同时还是一个音乐家,他花了很多功夫培养我
07:37
a sophomore, a freshman at SUNY Buffalo.
134
457160
3000
我当时还是一个在纽约州立大学水牛城念大一,大二的学生
07:40
He'd come up from Trumansburg to teach me
135
460160
5000
他会专程从Trumansburg赶来教我
07:45
not just about the Moog synthesizer, but we'd be sitting there --
136
465160
4000
不光是Moog合成器,我们就坐在那儿─
07:49
I'm studying physics at the time. This is 1969, 70, 71.
137
469160
3000
我当时还在攻读物理学。那是1969,70和71年。
07:52
We're studying physics, I'm studying physics,
138
472160
2000
我们就一起研究物理,我还在攻读物理学时,
07:54
and he's saying, "That's a good thing to do.
139
474160
2000
他就会说:“这是一个不错的选择。
07:56
Don't get caught up in electronic music if you're doing physics."
140
476160
2000
不要因为受电子音乐的影响而放弃追求物理。”
07:58
Mentoring me. He'd come up and
141
478160
3000
每次他来指导我物理时,
08:01
spend hours and hours with me.
142
481160
4000
他会几小时,几小时地花时间教导我。
08:05
He wrote a letter of recommendation for me to get into graduate school.
143
485160
3000
我进研究生学院的推荐信也是他给我写的。
08:08
In the background, my bicycle.
144
488160
2000
(回到这张照片)背景是我的自行车。
08:10
I realize that this picture was taken at a friend's living room.
145
490160
3000
从这个背景我意识到这是我朋友的客厅。
08:13
Bob Moog came by and hauled a whole pile of equipment
146
493160
3000
Bob(就是Robert) Moog带了一大堆的装置过来
08:16
to show Greg Flint and I things about this.
147
496160
2000
来向我和Greg Flint演示这些东西。
08:18
We sat around talking about Fourier transforms,
148
498160
2000
我们就坐在那里讨论傅立叶变换。
08:20
Bessel functions, modulation transfer functions,
149
500160
3000
贝色函数, 调制变换函数,
08:23
stuff like this.
150
503160
3000
以及类似的东西。
08:28
Bob's passing this past summer has been a loss to all of us.
151
508160
3000
Bob(Robert)去年夏天的过世对我们所有人来说是个很大的损失。
08:31
Anyone who's a musician has been profoundly influenced by Robert Moog.
152
511160
4000
任何一个音乐家都深受Robert Moog的影响。
08:36
(Applause)
153
516160
2000
(鼓掌)
08:38
And I'll just say what I'm about to do. What I'm about to do --
154
518160
5000
我即将告诉你我要干什么。我要干的是─
08:43
I hope you can recognize that there's a distorted sine wave,
155
523160
4000
我希望你们都能辨认出照片里的这个被扭曲的正弦波,
08:47
almost a triangular wave upon this Hewlett-Packard oscilloscope.
156
527160
4000
它从这个HP的示波器看上去几乎就是一个三角波。
08:53
Oh, cool. I can get to this place over here, right?
157
533160
4000
哦对了。我可以切换话题了对吗?
08:58
Kids. Kids is what I'm going to talk about -- is that okay?
158
538160
2000
孩子。孩子是我的下一个话题─可以吗?
09:00
It says kids over here, that's what I'd like to talk about.
159
540160
4000
我的手上写的是孩子,那就是我下一个要讲的话题了。
09:04
I've decided that, for me at least,
160
544160
4000
我已经决定了,至少对我来说,
09:08
I don't have a big enough head.
161
548160
4000
我在这方面没有什么创意。
09:13
So I think locally and I act locally.
162
553160
3000
所以我的所作所为都只能局限在一小部分地方。
09:16
I feel that the best way I can help out anything is to help out very, very locally.
163
556160
4000
我感到最好的能够帮助孩子的方法是帮助当地的孩子。
09:20
So Ph.D. this, and degree there, and the yadda yadda.
164
560160
5000
不管你有什么样的文凭。
09:25
I was talking about this stuff to
165
565160
4000
一年前
09:29
some schoolteachers about a year ago.
166
569160
2000
我在跟一些学校教师谈论这个问题。
09:31
And one of them, several of them would come up to me and say,
167
571160
2000
然后他们中的一些人会对我说,
09:33
"Well, how come you ain't teaching?"
168
573160
2000
“为什么你不去教那些孩子呢?”
09:35
And I said, "Well, I've taught graduate --
169
575160
1000
我说:“我过去教的是研究生─
09:36
I've had graduate students, I've taught undergraduate classes."
170
576160
3000
我同样也教过本科生。”
09:39
No, they said, "If you're so into kids and all this stuff,
171
579160
2000
他们说:“假如你对孩子的教育问题如此关心,
09:41
how come you ain't over here on the front lines?
172
581160
3000
那你为什么不过来亲自教授他们?
09:44
Put your money where you mouth is."
173
584160
4000
你应当说到做到,而不是光耍嘴皮子。”
09:48
Is true. Is true. I teach eighth-grade science four days a week.
174
588160
6000
他们说的是对的。我就一周花四天去教八年级科学。
09:54
Not just showing up every now and then.
175
594160
2000
我不是隔三岔五地来教书。
09:56
No, no, no, no, no. I take attendance.
176
596160
4000
我上课要点名。
10:00
I take lunch hour. (Applause)
177
600160
3000
我还有午间休息。(鼓掌)
10:03
This is not -- no, no, no, this is not claps.
178
603160
3000
你们没有必要为我鼓掌。
10:06
I strongly suggest that this is a good thing for each of you to do.
179
606160
4000
我强烈建议这是你们每一个人应当做的事情。
10:10
Not just show up to class every now and then.
180
610160
2000
不只是隔三岔五地去一下教室。
10:12
Teach a solid week. Okay, I'm teaching three-quarters time, but good enough.
181
612160
4000
好好地教一个星期。我一星期内只花四分之三的时间教书,不过已经足够好了。
10:16
One of the things that I've done for my science students
182
616160
2000
我是这样教导修我科学课程的学生的
10:18
is to tell them, "Look, I'm going to teach you college-level physics.
183
618160
3000
我对他们说:“我要教你们大学水平的物理。
10:21
No calculus, I'll cut out that.
184
621160
2000
但是我不会涉及到微积分。
10:23
You won't need to know trig.
185
623160
2000
你不需要懂得几何学。
10:25
But you will need to know eighth-grade algebra,
186
625160
3000
但是你需要懂得八年级程度的代数,
10:28
and we're going to do serious experiments.
187
628160
2000
然后我们要做真正的实验。
10:30
None of this open-to-chapter-seven-and-do-all-the-odd-problem-sets.
188
630160
3000
我是不会给你们一本书然后光叫你们做书后的习题的,
10:33
We're going to be doing genuine physics."
189
633160
2000
我要教你们常识性的物理学。”
10:36
And that's one of the things I thought I'd do right now.
190
636160
2000
然后我就要向你们展示我是如何给他们做试验的。
10:38
(High-pitched tone)
191
638160
3000
(高频段音)
10:41
Oh, before I even turn that on,
192
641160
2000
噢,在我把机器打开前,
10:43
one of the things that we did about three weeks ago in my class --
193
643160
4000
我要向你们解释大约三周前我给课堂里讲的东西─
10:47
this is through the lens, and one of the things we used a lens for
194
647160
2000
这是镜片的许多应用之一,就是通过镜片
10:49
was to measure the speed of light.
195
649160
2000
来测量光速。
10:51
My students in El Cerrito -- with my help, of course,
196
651160
3000
我在El Cerrito的学生通过我的帮忙
10:54
and with the help of a very beat up oscilloscope --
197
654160
3000
和一个非常陈旧的示波器的帮忙,
10:57
measured the speed of light.
198
657160
1000
来测量光速。
10:58
We were off by 25 percent. How many eighth graders do you know of
199
658160
5000
我们得到的结果有25%的偏差。你们知道有多少八年级学生
11:03
who have measured the speed of light?
200
663160
2000
做过光速测试?
11:05
In addition to that, we've measured the speed of sound.
201
665160
3000
除此之外,我们还测量过音速。
11:08
I'd love to measure the speed of light here.
202
668160
2000
我现在就要向你们展示测音速的实验。
11:10
I was all set to do it and I was thinking, "Aw man,"
203
670160
2000
当我决定给你们做这个实验的时候我很兴奋地在想,“老天”
11:12
I was just going to impose upon the powers that be,
204
672160
2000
我只是想不断加强这方面的能力,
11:15
and measure the speed of light.
205
675160
1000
来测量光速。
11:16
And I'm all set to do it. I'm all set to do it,
206
676160
4000
我很兴奋地想要做测光速的实验,
11:20
but then it turns out that to set up here, you have like 10 minutes to set up!
207
680160
4000
但是假如要把仪器准备好需要花费10分钟的时间!
11:24
And there's no time to do it.
208
684160
2000
但现在不容许我花那么多时间。
11:26
So, next time, maybe, I'll measure the speed of light!
209
686160
2000
所以下次也许我会向大家展示测光速的实验!
11:28
But meanwhile, let's measure the speed of sound!
210
688160
2000
不过现在,我们来测音速吧!
11:30
Well, the obvious way to measure the speed of sound
211
690160
2000
测量音速最简单的方法
11:32
is to bounce sound off something and look at the echo.
212
692160
3000
就是让声波反弹然后测量回声的时间。
11:35
But, probably -- one of my students, Ariel [unclear], said,
213
695160
5000
然后我的一个学生,Ariel,说,
11:40
"Could we measure the speed of light using the wave equation?"
214
700160
3000
“我们能不能通过波的定理公式来测量光速?”
11:43
And all of you know the wave equation is
215
703160
2000
你们都知道波的定理公式是:
11:45
the frequency times the wavelength of any wave ...
216
705160
6000
频率乘以任何波的波长…
11:51
is a constant. When the frequency goes up,
217
711160
3000
是一个常量。当频率变大,
11:54
the wavelength comes down. Wavelength goes up,
218
714160
3000
波长减小。当波长增大
11:57
frequency goes down. So, if we have a wave here --
219
717160
4000
频率变小。所以我们这里有一个波─
12:02
over here, that's what's interesting --
220
722160
4000
看这里,这是一个很有趣的现象─
12:06
as the pitch goes up, things get closer,
221
726160
3000
当音频变高时,波跟波之间的距离变小
12:09
pitch goes down, things stretch out.
222
729160
2000
当音频变低时,波跟波之间的距离拉大了。
12:13
Right? This is simple physics.
223
733160
2000
这是最简单的物理学,不是吗?
12:15
All of you know this from eighth grade, remember?
224
735160
3000
你们所有人在八年级的时候就学过了,记不记得?
12:18
What they didn't tell you in physics -- in eighth-grade physics --
225
738160
4000
但是他们在八年级物理课上没有告诉你的是
12:22
but they should have, and I wish they had,
226
742160
3000
(他们应该告诉你的,我希望他们告诉你)
12:25
was that if you multiply the frequency times the wavelength of sound
227
745160
4000
当你将频率乘以声音或者
12:29
or light, you get a constant.
228
749160
4000
光的波长,你将得到一个常量。
12:33
And that constant is the speed of sound.
229
753160
2000
而这个常量就是音速。
12:36
So, in order to measure the speed of sound,
230
756160
3000
所以为了测量音速,
12:39
all I've got to do is know its frequency. Well, that's easy.
231
759160
4000
我只要知道频率就可以了。这是非常简单的。
12:43
I've got a frequency counter right here.
232
763160
2000
我这里有一个频率测量仪。
12:45
Set it up to around A, above A, above A. There's an A, more or less.
233
765160
5000
将它设置到大致在“A”这里。
12:50
Now, so I know the frequency.
234
770160
4000
现在我就知道它的频率了。
12:55
It's 1.76 kilohertz. I measure its wavelength.
235
775160
4000
是1.76千赫兹。我现在测量它的波长。
13:00
All I need now is to flip on another beam,
236
780160
3000
我只要在示波器上打开另一个输入端,
13:03
and the bottom beam is me talking, right?
237
783160
3000
就是底下的那个输入端,对吗?
13:06
So anytime I talk, you'd see it on the screen.
238
786160
4000
所以每次我说话的时候,你可以在屏幕上看见我的声波。
13:11
I'll put it over here, and as I move this away from the source,
239
791160
4000
我将它放在这里,然后当我将它从声源那里移开时,
13:15
you'll notice the spiral.
240
795160
4000
你会注意到波会螺旋形地展开。
13:20
The slinky moves. We're going through different nodes of the wave,
241
800160
5000
这样,贴身移动。我们正在经过波的不同质点,
13:25
coming out this way.
242
805160
2000
从这里经过。
13:27
Those of you who are physicists, I hear you rolling your eyes,
243
807160
2000
对于在座的物理学家们,我知道你们感到很无聊,
13:29
but bear with me. (Laughter)
244
809160
2000
但你们也就忍一忍吧。(众笑)
13:31
To measure the wavelength,
245
811160
3000
要测量波长,
13:34
all I need to do is measure the distance from here --
246
814160
5000
我只要测量从这里
13:40
one full wave -- over to here.
247
820160
2000
到这里,一整段波的长度。
13:42
From here to here is the wavelength of sound.
248
822160
3000
从这里到这里就是声波的波长。
13:45
So, I'll put a measuring tape here, measuring tape here, move it back over to here.
249
825160
7000
然后,我在这里有一把卷尺,从这里,然后移到这里。
13:53
I've moved the microphone 20 centimeters.
250
833160
4000
我大概将麦克风移动了20厘米。
13:57
0.2 meters from here, back to here, 20 centimeters.
251
837160
5000
也就是0.2米。
14:04
OK, let's go back to Mr. Elmo.
252
844160
5000
然后我们回到Elmo先生这里
14:10
And we'll say the frequency is 1.76 kilohertz, or 1760.
253
850160
6000
我们说频率是1.76千赫,或者1760赫兹。
14:17
The wavelength was 0.2 meters.
254
857160
4000
波长是0.2米。
14:21
Let's figure out what this is.
255
861160
4000
(用计算尺计算)我们来看看结果是什么。
14:25
(Laughter) (Applause)
256
865160
7000
(众笑+鼓掌)
14:33
1.76 times 0.2 over here is 352 meters per second.
257
873160
7000
1.76乘以0.2得到的是每秒352米。
14:40
If you look it up in the book, it's really 343.
258
880160
6000
假如你在书上去查音速的理论,它的值是343米/秒。
14:46
But, here with kludgy material, and lousy drink --
259
886160
2000
尽管我们这里受到陈旧设备以及难喝饮料的影响─
14:48
we've been able to measure the speed of sound to --
260
888160
4000
我们还是能够比较精确地测量
14:53
not bad. Pretty good.
261
893160
1000
音速了。不坏。
14:55
All of which comes to what I wanted to say.
262
895160
4000
这一切归总到我想说的。
15:00
Go back to this picture of me a million years ago.
263
900160
5000
回到那幅很久远的照片。
15:05
It was 1971, the Vietnam War was going on,
264
905160
5000
那是1971年,当时还在打越南战争
15:10
and I'm like, "Oh my God!"
265
910160
3000
我的反应是,“天哪”
15:13
I'm studying physics: Landau, Lipschitz, Resnick and Halliday.
266
913160
3000
我在攻读物理:朗道(Landau),Lipschitz,Resnick和Halliday。
15:16
I'm going home for a midterm. A riot's going on on campus.
267
916160
2000
那天我在期中考试结束后回家的路上,遭遇到了校园暴乱。
15:18
There's a riot! Hey, Elmo's done: off.
268
918160
9000
那是一个暴乱!噢,Elmo的事情已经结束了,关掉。
15:27
There's a riot going on on campus,
269
927160
2000
那是一个在校园里的暴乱,
15:29
and the police are chasing me, right?
270
929160
3000
然后警察在追捕我,
15:32
I'm walking across campus. Cop comes and looks at me and says,
271
932160
3000
我在校园里走。警察过来看到我说
15:35
"You! You're a student."
272
935160
2000
“你!你是个学生。”
15:37
Pulls out a gun. Goes boom!
273
937160
2000
他抽出一把枪。“砰”地一声!
15:39
And a tear gas canister the size of a Pepsi can goes by my head. Whoosh!
274
939160
4000
一个可乐罐大小的催泪弹擦着我的头皮飞过。
15:43
I get a breath of tear gas and I can't breathe.
275
943160
3000
我吸到一口催泪瓦斯然后我不能呼吸。
15:46
This cop comes after me with a rifle.
276
946160
2000
那个警察拿着一把来福枪来追我。
15:48
He wants to clunk me over the head!
277
948160
2000
他想要用枪柄砸我的头!
15:50
I'm saying, "I got to clear out of here!"
278
950160
3000
我当时就想:“我一定要逃出去!”
15:53
I go running across campus quick as I can. I duck into Hayes Hall.
279
953160
5000
我一路飞奔穿过整个校园。藏到Hayes楼里
15:59
It's one of these bell-tower buildings.
280
959160
2000
Hayes楼是学校里几个钟楼之一。
16:01
The cop's chasing me.
281
961160
1000
那个警察在追我。
16:03
Chasing me up the first floor, second floor, third floor.
282
963160
2000
从一楼追到二楼,三楼。
16:05
Chases me into this room.
283
965160
1000
将我逼到一间房间里。
16:06
The entranceway to the bell tower.
284
966160
2000
那间房间通向钟塔的门口
16:08
I slam the door behind me, climb up,
285
968160
2000
我将房间的门关紧,顺着钟塔向上爬,
16:10
go past this place where I see a pendulum ticking.
286
970160
2000
一直爬到钟摆哪里。
16:12
And I'm thinking, "Oh yeah,
287
972160
2000
我忽然想到,对了,
16:14
the square root of the length is proportional to its period." (Laughter)
288
974160
2000
摆绳长度的平方根和钟摆的周期是成正比的。(众笑)
16:17
I keep climbing up, go back.
289
977160
2000
我继续往上爬,又倒退下来。
16:19
I go to a place where a dowel splits off.
290
979160
2000
我爬到钟顶端定位梢分开的地方。
16:21
There's a clock, clock, clock, clock.
291
981160
1000
那里就是一个巨大的钟。
16:22
The time's going backwards because I'm inside of it.
292
982160
2000
时间是对我来说是倒着走的因为我在钟的里面。
16:24
I'm thinking of Lorenz contractions and Einsteinian relativity.
293
984160
4000
我的脑海里浮现出洛仑兹收缩和爱因斯坦相对论。
16:28
I climb up, and there's this place, way in the back,
294
988160
3000
我继续向上爬,在钟的很背后,
16:31
that you climb up this wooden ladder.
295
991160
2000
有一把木梯。
16:33
I pop up the top, and there's a cupola.
296
993160
2000
我从钟的顶端爬出,那是一个圆顶的顶篷。
16:35
A dome, one of these ten-foot domes.
297
995160
2000
一个十尺高的圆顶。
16:37
I'm looking out and I'm seeing the cops bashing students' heads,
298
997160
3000
我从那里向外看,看到警察们猛击学生们的头部,
16:40
shooting tear gas, and watching students throwing bricks.
299
1000160
2000
放射催泪弹,然后学生们以扔砖块回击。
16:42
And I'm asking, "What am I doing here? Why am I here?"
300
1002160
3000
我扪心自问,我在这里干什么?我为什么要在这里?
16:45
Then I remember what my English teacher in high school said.
301
1005160
3000
然后我回想到我高中英语老师说的话。
16:48
Namely, that when they cast bells,
302
1008160
4000
也就是人们在浇铸钟铃的时候,
16:52
they write inscriptions on them.
303
1012160
3000
会在钟上写字。
16:55
So, I wipe the pigeon manure off one of the bells, and I look at it.
304
1015160
4000
于是我把鸽子屎从钟上抹掉,然后看着钟
16:59
I'm asking myself, "Why am I here?"
305
1019160
1000
我在问自己,我来到这个世界的意义是什么?
17:02
So, at this time, I'd like to tell you the words inscribed
306
1022160
4000
所以在这里我要告诉你在Hayes钟楼上
17:06
upon the Hayes Hall tower bells:
307
1026160
4000
的钟上写着:
17:10
"All truth is one.
308
1030160
5000
万相归一。
17:15
In this light, may science and religion endeavor here
309
1035160
6000
在这道光芒下,愿科学与宗教为了人类稳定的进化而协力,
17:21
for the steady evolution of mankind, from darkness to light,
310
1041160
4000
让人类自黑暗走向光明,
17:25
from narrowness to broad-mindedness, from prejudice to tolerance.
311
1045160
5000
自偏见走向宽容,自狭隘走向开放。
17:33
It is the voice of life, which calls us to come and learn."
312
1053160
7000
这是生命的声音,呼唤我们前来,在此学习。
17:41
Thank you very much.
313
1061160
2000
谢谢大家。
关于本网站

这个网站将向你介绍对学习英语有用的YouTube视频。你将看到来自世界各地的一流教师教授的英语课程。双击每个视频页面上显示的英文字幕,即可从那里播放视频。字幕会随着视频的播放而同步滚动。如果你有任何意见或要求,请使用此联系表与我们联系。

https://forms.gle/WvT1wiN1qDtmnspy7