History and use of the metric system?

Answer 1

The metric system is a system of measurement based on the metre and the gram. It exists in several minor variations, with different choices of base units (CGS, MKS, etc), though these do not affect its day-to-day use. Over the last two centuries, different variants have been considered the metric system. Since the 1960s the International System of Units (SI, Systeme International) is the internationally recognised standard metric system. Metric units are widely used around the world for both everyday and scientific purposes. One goal of the metric system is to have a single unit for any physical quantity. All lengths and distances, for example, are measured in metres, or thousandths of a metre (millimetres), or thousands of metres (kilometres), and so on. There is no profusion of different units with different conversion factors, such as inches, feet, yards, fathoms, rods, chains, furlongs, miles, nautical miles, leagues, etc. Multiples and submultiples are related to the fundamental unit by factors of powers of ten, so that one can convert by simply moving the decimal place: 1.234 metres is 1234 millimetres, 0.001234 kilometres, etc. The use of fractions, such as 2/5 of a metre, is not prohibited, but uncommon. Time, on the other hand, has not been metricated in everyday use: years, months, weeks, days, hours, minutes, and seconds, with non-decimal conversion factors, are used. The second and its submultiples, (e.g. microsecond), are used in scientific work, but the traditional units of time are more often used than decimal multiples of a second. The original metric system was intended to be used with the units of time of the French Republican Calendar, but these fell into disuse along with the calendar. In the late 18th century, Louis XVI of France charged a group to develop a unified, natural and universal system of measurement to replace the disparate systems then in use. This group, which included such notables as Lavoisier, produced the metric system, which was then adopted by the revolutionary government of France. In the early metric system there were several fundamental or base units, the grad or grade for angles, the metre for length, the gram for mass and the litre for volume. These were derived from each other via the properties of natural objects, mainly the Earth and water: 1 metre was originally defined as 1/10,000,000th of the geographic-pole- to-equator distance, and 1 litre of water weighs 1 kilogram and equals 1 square decimetre. (1000 cubic centimetres - cc) Other units were derived from this, such as the Celsius temperature scale, where water freezes at 0°C and boils at 100°C at standard pressure.