We have 266, as some of you might know who saw me counting ping-pong balls the other day in office hours.
看到了这些发泡胶球事实上,可以当作单层金原子核,我们有266个乒乓球。
I started playing when I was about nine, hitting balls with my brother and my dad.
我大概九岁的时候开始打,跟我哥哥和爸爸打。
But I'm sure you can easily see how these styrofoam balls could, in fact, be a mono layer of gold nuclei.
这个实验怎么工作的,我们先来做些计算,但我相信你们都已经。
Except for electromagnetism, the basics of mechanics, which is the motion of Billiard balls and trucks and marbles and whatnot, was set up by Newton.
除电磁学外,力学的基础,也就是台球,卡车,弹球以及其它小玩意儿的运动原理,都是由牛顿建立起来的
They are out there with little balls, fliers and everything, and "come, come come to our group."
扔着纸团,传单,各种招揽,来吧,快来我们社团“
It is like an elastic collision between billiard balls.
就像是台球在,台球桌上发生弹性碰撞。
and hit balls as well from the back of elephants, amongst other things.
是从象背上去击球,除此之外都是一样的。
So we can build a machine that could sort red balls from blue balls.
我们就能制造一台,可以分辨红球和蓝球的机器
So, 13 backscattered. TAs, if you can maybe pick up these ping-pong balls for me.
把这些球捡起来,我觉得如果,我摔倒一定很搞笑。
Those of you who have your ping-pong balls can now begin the experiment.
好,我们会到这边来把球给你们,已经拿到球的同学就可以开始试验了。
We have 266 ping-pong balls, and we need someone, hopefully you, to be some radioactive material that are going to be emitting these ping-pong balls. And when the time comes, in just a minute, I'll ask the TAs to come down and hand these out very quickly to you, so we can do this experiment.
你们有些人那天,看到我在办公室数乒乓球,我们需要几个人,希望是你,来作为放射材料,放射这些乒乓球,等会我会让助教,把这些球发给你们。
All right. So, we'll come around and get ping-pong balls to the rest of you.
还有什么问题吗?如果你们,还没有乒乓球的话请举手,还有问题吗?
PROFESSOR: So, as you're getting your ping-pong balls -- do not throw them yet.
如果你觉得,你的准心很好的话,你们现在都拿到乒乓球。
I am modeling them as billiard balls of a finite dimension.
我把它们想象成具有有限尺寸的台球。
But in our case, the probability of backscattering is going to be the number of balls that backscatter, and that's going to be divided by the total number of ping-pong balls.
用20除以132000,但现在背散射,的概率是被散射回来的小球,除以总的小球数,你们记得。
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