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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How Is Maillardet's Automaton Still Wowing Us After 200 Years?
09:28

How Do Tiny Capers Pack Such a Big Flavor Punch?
06:35

What Do A.M., P.M., and SOS Stand For?
09:18