How long, how fast, how hot, how heavy?

The birth of the calendar

A year is a long time. So, long ago, people decided to divide it into shorter time periods. About five thousand years ago, the Sumerians divided the year into twelve “moons.” Each moon had thirty…

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How Things Work

Pictures that fool your eyes

Do you know that a \”movie” doesn’t really move? Your eyes make it look as if it’s moving! A movie is made with a camera that takes pictures very fast—twenty-four pictures in a second. Each…

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Holidays and Birthdays

The soldier from Poland

> Pulaski Day > > October 11 Count Casimir Pulaski was a Polish nobleman who fought for the Americans in the Revolutionary War. While in France in 1777, Pulaski learned of the American Revolution…

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