About Meters

The meter (m) is the base unit of length in the International System of Units (SI). It is defined as the length of the path travelled by light in a vacuum during a time interval of 1/299,792,458 of a second. This definition was adopted in 1983.

The meter was first introduced in France in the late 18th century. Early definitions were based on the Earth's circumference (one ten-millionth of the distance from the equator to the North Pole along a meridian). Later, it was defined by a prototype platinum-iridium bar. The current definition based on the speed of light provides a more precise and universally reproducible standard.

Meters are used worldwide for a vast range of measurements, including:

• Everyday distances (e.g., length of a room, height of a building).
• Scientific research and engineering.
• Track and field events (e.g., 100-meter dash).
• Manufacturing and construction specifications.
• Geographic measurements (often in the form of kilometers).

The meter is used with SI prefixes to denote multiples and submultiples:

• Kilometer (km): 1,000 meters
• Hectometer (hm): 100 meters
• Dekameter (dam): 10 meters
• Decimeter (dm): 0.1 meters (1/10th of a meter)
• Centimeter (cm): 0.01 meters (1/100th of a meter)
• Millimeter (mm): 0.001 meters (1/1,000th of a meter)
• Micrometer (µm): 0.000001 meters (1/1,000,000th of a meter)
• And so on for nanometers (nm), picometers (pm), etc.

To help visualize a meter:

• The height of a standard doorknob is often about 1 meter from the floor.
• Many adult humans are between 1.5 and 2 meters tall.
• A typical guitar is about 1 meter long.
• The width of a standard doorway is often slightly less than 1 meter.