## Meters

**Abbreviation/Symbol:**

m

**Worldwide use:**

The metre, as part of the metric system, is used as a measure of distance across the globe, the primary exception being the United States, where the imperial system is used for most purposes.

The meter, a unit of length in the metric system, is widely used across the globe for various applications. Adopted by the International System of Units (SI), the meter is recognized as the standard unit of length in most countries. Its widespread use can be attributed to several factors.

One of the key reasons for the worldwide use of meters is the simplicity and consistency of the metric system. The metric system, with its base unit of 1 meter, allows for easy conversion between different units of length, such as centimeters, kilometers, and millimeters. This uniformity makes it convenient for scientists, engineers, and everyday users to communicate and work with measurements across different fields and industries.

Moreover, the use of meters is not limited to scientific or technical applications. It is also commonly used in everyday life, such as measuring distances, dimensions of objects, or even the height of individuals. This universality of the meter makes it a practical and accessible unit of measurement for people around the world.

**Definition:**

The meter is a fundamental unit of length in the International System of Units (SI). Since 1983, it has been defined as the distance traveled by light in a vacuum during a specific time interval. More precisely, the meter is defined as the length of the path traveled by light in a vacuum in 1/299,792,458 of a second. This definition was established in 1983 by the General Conference on Weights and Measures (CGPM) and is based on the speed of light, which is a universal constant.

1 m is equivalent to 1.0936 yards, or 39.370 inches.

The definition of the meter based on the speed of light allows for precise and reliable measurements, as the speed of light is a constant that can be accurately determined. This definition also ensures that the meter remains consistent regardless of the location or time, making it a universal unit of length.

**Origin:**

A decimal-based unit of measurement had been proposed as early as the late 17th century, with the name metre being derived from the Greek métron katholikón, meaning 'universal measure'.

An early definition of a metre was "the length of a pendulum with a half-period of one second" By the 18th century a definition based on "one ten-millionth of the length of the Earth's meridian along one quadrant" (the distance from the equator to the North Pole) was gaining favour, and this was the accepted definition when France adopted the metric system in 1795.

Prototype metre bars - first brass, later platinum then a platinum/iridium alloy - were manufactured as successive standards of the metre. In 1960 the metre was redefined using the wavelengths of radiation, before the current definition, relating the metre to the speed of light, was adopted in 1983.

To determine the length of the meter, the French Academy of Sciences turned to the Earth itself. They decided to use one ten-millionth of the distance from the North Pole to the equator as the basis for the meter. This distance was measured along a meridian passing through Paris, from Dunkirk to Barcelona. The task of accurately measuring this distance fell to two French astronomers, Jean-Baptiste Delambre and Pierre Méchain.

Over the course of several years, Delambre and Méchain conducted a series of measurements and calculations to determine the length of the meridian arc. Their work was not without challenges, as they had to contend with difficult terrain, adverse weather conditions, and inaccuracies in their instruments. However, their dedication and perseverance paid off, and in 1799, they presented their findings to the French government.

Based on their measurements, the meter was officially defined as one ten-millionth of the distance from the North Pole to the equator. This definition was later refined and standardized, leading to the adoption of the meter as an international unit of length and defined against the speed of light in a vacuum.

**Common references:**

A human male of average height is around 1.75 m tall.

The hurdles used in Olympic 110 m hurdles races are 1.067 m high.

The tallest building in the world (as of 2012), the Burj Khalifa in Dubai, is 828 m tall.

The Empire State Building in New York City is 381 m high.

The standard gauge of railway tracks (the distance between the rails) is 1.435 m.

**Usage context:**

The meter is a fundamental unit of length in the International System of Units (SI). It is widely used in various fields and contexts due to its versatility and ease of measurement. One of the most common usage contexts of meters is in everyday life for measuring distances and lengths. Whether it is measuring the height of a person, the length of a room, or the distance between two locations, meters provide a convenient and standardized unit for such measurements.

In the field of construction and engineering, meters are extensively used for measuring dimensions of buildings, roads, and other structures. Architects and engineers rely on accurate meter measurements to ensure precise designs and constructions. Similarly, in the field of surveying and mapping, meters are crucial for determining land boundaries, creating topographic maps, and conducting geodetic surveys.

Meters are also widely used in scientific research and experimentation. In physics, for instance, meters are used to measure wavelengths, distances between objects, and the size of particles. In chemistry, meters are employed to measure the length of chemical bonds and the dimensions of molecules. Furthermore, meters are utilized in various branches of engineering, such as electrical engineering, where they are used to measure electrical cable lengths and signal wavelengths.