An electric toothbrush gets power from its base without the help of metal contacts. Find out how this sealed system works in the following podcast from HowStuffWorks.com.
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How Did the Penn Center Become a Civil Rights Sanctuary?
09:53

BrainStuff Classics: Why Is Cramming the Worst Way to Study?
05:55

How Can We Separate Ninja Fact from Ninja Fiction?
07:38