Why do bottles of soft drinks come in liters, when cans come in ounces? Why do we measure milk by the gallon? Why does a car’s speedometer show speeds in both miles per hour and kilometers per hour? And, most importantly, why is the United States one of the few countries in the world that does not mainly use the metric system?
The Liter is a Little Bit More
Scientists love the metric system because it’s easy to convert between units. If you can multiply and divide by 10, you can handle metric measurements. Meanwhile, the U.S. customary system depends on multiples of 3, 12, 8, and 16. It’s not easy to convert between inches and miles in your head. On the other hand, converting between centimeters to kilometers is just a matter of moving decimal points. Over time, the U.S. has gradually moved toward adopting the metric system. For instance, many manufacturers label their packaging in both ounces and grams. This enables them to sell their products in other countries. Doctors and nurses record weights and medication dosages in metric units. Mechanics keep both metric and non-metric tools on hand so that they can fix both domestic and foreign cars.
As time goes on, use of the metric system will continue to spread throughout America. The next time you visit a store, keep your eyes open. You might be surprised by where the metric system pops up.
Check out the following videos for more about the metric system versus the customary system.