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。

麻省理工公开课 - 化学原理课程节选

Sam All right. So, we'll move this up to the front in just a minute, but I'm going to explain how this experiment works and we'll do the calculation first before the excitement breaks out.

好的，这是她的女儿,被背带背她在胸前，这是Patti，Christie博士，好的，我们等会,会把它移到前面,但我要先解释下。

麻省理工公开课 - 化学原理课程节选