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The World's Roundest Object (and Why it Exists)

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The world's roundest object helps solve the longest running problem in measurement -- how to define the kilogram. A kilogram isn't what it used to be. Literally. The name, weight, and definition of a kilogram has been changing constantly since its invention, and the Avogadro Project looks to change that. 

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TED-Ed Best of Web are exceptional, user-created lessons that are carefully selected by volunteer teachers and TED-Ed staff.

Meet The Creators