Early life. Ferdinand Magellan was born about 1480 to a noble family in Portugal. As a boy, he served the queen of Portugal as a page, and studied cartography and navigation tenaciously.
There are seven fundamental units: the metre, kilogram, second, ampere, kelvin, candela, and mole; and two supplementary units: the radian and the steradian. All other units are derived by multiplication or division of these units without the use of numerical factors. SI units in Medicine Expand. International System of Units n. Abbr. SI. A complete, coherent system of units used for scientific work, in which the fundamental quantities are length, time, electric current, temperature, mass, luminous intensity, and amount of substance. Also called International System. SI unit. Any of the units of measure in the International System.
SI derived unit. The International System of Units (SI) specifies a set of seven base units from which all other SI units of measurement are derived. Each of these other units (SI derived units) is either dimensionless or can be expressed as a product of (positive or negative, but usually integral) powers of one or more of the base units. For example, the SI derived unit of area is the square metre (m2), and the SI derived unit of density is the kilogram per cubic metre (kg/m3 or kg mâ3). The degree Celsius (see the table below) has a somewhat unclear status, and is arguably an exception to this rule. The names of SI units are written in lowercase.