Units from the metric system can be used to describe the mass, volume or length of an object. Mass is measured in grams (g) and kilograms (kg). Volume is measured in millilitres (ml) and litres (l).

Before measuring something, it is important to know which unit to use. Estimating its approximate size by comparing it with a more familiar object can help. In order to find a suitable unit of measure ...

Americans have long used diverse weights and measures, reflecting their diverse origins. From colonial times, converting from one unit to another was part of courses in commercial arithmetic. The ...

A nanometer (nm) is a unit of length in the metric system, defined as one billionth (10-9) of a meter (m). The meter is the base unit of length in the International System of Units (SI), making the ...