Physics and History of Why USA uses 120 volts and not 220 volts

Why do 1/3 of the countries in the world use around 110 volts and the other 2/3rds use around 220 volts? I go through the history and the physics to explain why it is so confusing.

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As usual, a big thank you to the fabulous Kim Nalley for singing "electricity" and some background music. www.kimnalley.com

Song: Overture/And All That Jazz
Artist: Catherine Zeta-Jones;Taye Diggs;Renée Zellweger
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