Science at Home Videos

Announcer: Frostbite Theater presents... Cold Cuts! No baloney!

Joanna and Steve: Just science!

Joanna: Hi! I'm Joanna!

Steve: And I'm Steve!

Joanna: This is data run number five in our experiment to measure the half-life of metastable barium-137. If you want to know more about the equipment and materials we're using, please see the first video in this series.

Steve: Joanna and I have already measured the background rate in this room. If you're using the Geiger-Müeller tube, the average background rate is 46.1 counts per minute. If you're using the scintillator with the photomultiplier tube, the average background rate is 3,454.4 counts per minute. If you don't know what to do with that information, don't worry. We'll explain how to use it in the third and final video of this series.

Joanna: We're going to let the scalers count the decays for five minutes. Your job is to record the total number of counts as time goes by. For example, you may decide to take data every fifteen seconds. You can use the on-screen clock to keep track of time.

Steve: Remember that the GM tube is much less sensitive than the photomultiplier tube. While this gives it a lower count rate that's easier to read, it has a higher statistical error. You'll get better data using the photomultiplier tube even if you can't tell what the last couple of digits are.#noname And, don't be afraid to hit the pause button if you need to. We won't be offended.

Joanna: So, if you're ready!

Three, two, one, start!

Steve: Okay! That's it for the data!

Joanna: Thanks for watching! I hope you'll join us for the third and final video where we'll show you how to calculate the half-life with the data you've collected!

Steve: Data.

Joanna: Data. You've been watching too much Star Trek.

Steve: Yeah. Probably.