If you live in the United States of America, you may be accustomed to using what is known as the U.S. Customary System for measuring things — the distance between home and school (4 miles), the weight of your pet rabbit (2 pounds).

If you live in the United Kingdom of Great Britain and Northern Ireland, as it is officially known, you may use the British Imperial System of measurement, in which some of the weights and measures are similar to their U.S. counterparts, while others are expressed in the metric system.

But if you live most anywhere else in the world — and if you are a scientist even in the United States or Great Britain, Antarctica or Peru, China or Zimbabwe — you're almost certainly using the metric system. Everything in the metric system is sorted neatly into groups of 10, whereas in the U.S. and British systems you sometimes run into odd measures such as the yard (36 inches) and the mile (5,280 feet).

The metric system is neat because it is understood and used by scientists around the world. It's also neat for another reason: The prefixes (first parts) of each unit are the same for each kind of measure. And the suffixes (last parts) change depending on what’s being measured. A suffix of “meter” always means length; “liter” always means volume, and “gram” always means weight. The prefixes, and their meanings, are:

Below are some of the many weight-and-measure conversions with which scientists deal every day of their working lives. After a while, the conversions are easy to approximate in your head, and you'll find yourself becoming sort of metrically bilingual.

Length

Weight

Volume

Temperature

Area

Water