SI: How the World Measures Up

SI / Units / Prefixes / Links

Mars Climate Orbiter Do you know that the United States lost a $125 million space probe in part because of a failure to communicate units of measure? Rather than communicating in a standard international system of measurement, some engineers working on the space probe used non-standard systems of measurement. The loss of the probe was catastrophic.

But the real problem is the tardiness of the United States to adopt the International System of Units (abbreviated SI) in all its trade, science, and public communications. While scientists around the world and international events like the Olympics use familiar SI units like the meter, the United States lags behind.

This portfolio presents SI's units, prefixes, and links to further information.

John December ( / 2002-12-10