In many watches, phosphor is mixed with a radioactive element that continously charges the phosphor, powering glowing watch hands. Learn more about glowing watch hands in this HowStuffWorks podcast.
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BrainStuff Classics: How Did Alchemy Create Chemistry?
07:11

How Did Sundown Towns Say the Quiet Part Out Loud?
11:35

Why Do We Yawn, and Why Is It Catching?
12:02