Miles mark the distance on a road trip. Cups measure ingredients when you bake. And inches show how tall you are. These units make up our system of measurement, known as the U.S. customary system, adapted from the British imperial system.
But most countries use a different system called the metric system. They measure in units like kilometers, liters, and grams. Only three countries in the world don’t use the metric system: Liberia, Myanmar, and the U.S.
Over the years, there have been attempts to go metric in the U.S. Though none ever fully caught on, we actually use a bit of both systems. For example, NASA uses some metric measurements in its space operations.
Some say it’s time for the U.S. to switch fully. They point out that the metric system is less confusing since it is based on units of 10. For example, 1,000 grams equals 1 kilogram. In the U.S. system, 16 ounces equals 1 pound. But others argue that it would be difficult for an entire country to learn a new way to measure.