The United States is one of three countries in the world that has not adopted the metric system, and that may fall to two if Burma embraces metrication. How did inches, feet, pounds, gallons, and other familiar United States customary units — formerly the Imperial System of measurement — come to separate the U.S. from centimeters, kilograms, liters, and more?

For the majority of recorded human history, units like the weight of a grain or the length of a hand weren’t exact and varied from place to place. Now, consistent measurements are such an integral part of our daily lives that it’s hard to appreciate what a major accomplishment for humanity they’ve been. Matt Anticole traces the wild history of the metric system.

Why the Metric System Matters from TED Ed.

There are more measurement vids in the archives, plus How the Ancient Greeks shaped modern mathematics.