The metric scale is the system of measurement used in the metric system. Unlike the customary system of measurements in the United States, the metric scale has units based on multiples of 10. For example, in the United States distance measurements, one foot equals 12 inches, three feet are equal to one yard and 5,280 feet are equal to one mile. In the metric scale, 10 centimeters are equal to one decimeter, 10 decimeters are equal to one meter and 1,000 meters are equal to one kilometer.

## Types of Metric Scales

Different metric scales exist for different types of measurements. The meter is the metric scale unit for length, the gram is the metric scale unit for mass -- which is weight divided by force of gravity -- and the liter is the metric scale unit for volume.

## Unit Prefixes in the Metric Scale

The units for the metric scale have prefixes that indicate the magnitude of the measured unit in relation to the base unit. These prefixes include "milli," for one-thousandth, "centi," for one-hundredth, "deci," for one-tenth, and "kilo," for 1,000 units. With the unit prefix and the unit, the magnitude of the measurement can be expressed and determined. For example, a millimeter is one-1,000th of a meter, a milligram is one-1,000th of a gram and a milliliter is one-1,000th of a liter. A kilometer is 1,000 meters.

## History of the Metric System

In 1790, France commissioned its Academy of Science to create a simple, decimal-based measurement system, and in 1840, the metric system became compulsory in France. By 1900, more than 35 nations had adopted the metric system. The United States has acts related to the metric system -- such as the Metric Study Act of 1968 -- but the metric system remains a recommended, but not mandatory, system of measurement. Instead, the country. uses the U.S. Customary System of Measurements, which is based on the English system of weights and measures that a few countries use. In the United States, product labeling on some retail products includes both the metric and the United States system, especially products in grocery stores. Tech products, such as computers and smartphones, for example, state the screen size in inches, but the storage, speed and other specs in metric units.

## Specific Scientific Uses

The metric units established for the metric scales have been standardized, not only for length, mass and volume, but also for other scientific measurements. For example, the ampere is the metric unit used to indicate the magnitude of electrical current and the candela is used to quantify the magnitude of light intensity. These units also are expressed with the milli-, centi-, deci- and kilo- prefixes.

## Advantages of the Metric System

One advantage of the metric scale is that it is easier for users to perform calculations. For instance, you can easily accomplish the conversion of kilometers to meters when you divide by 1,000. In the United States, when you convert miles to feet, you have to divide by 5,280. Not only is this conversion factor more difficult to remember, but the conversion often requires a calculator. United States scientists and engineers use the metric system, just as scientists and engineers in other parts of the world use the metric system and not the English system.

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