SI units

(noun)

International System of Units (abbreviated SI from French: Le Système international d'unités). It is the modern form of the metric system.

Related Terms

Examples of SI units in the following topics:

  • SI Unit Prefixes

    • The basic SI units can be expressed as fractions and multiples of basic units by using a set of simple prefixes.
    • Now that we know about the SI system and what it provides to the scientist and engineer, we can examine some aspects of actual measurement.
    • The SI system utilizes a standard system of prefixes to the basic units that allow them to be more relevant to and descriptive of relative magnitude.
    • Briefly review the basic SI units before you study the prefixes.
    • A prefix may be used to identify multiples of the original unit or fractions of the original unit.

  • Prefixes and Other Systems of Units

    • SI prefixes precede a basic unit of measure to indicate a multiple or fraction of the unit.
    • A metric prefix, or SI prefix, is a unit prefix that precedes a basic unit of measure to indicate a multiple or fraction of the unit.
    • Some units that are widely used are not a part of the International System of Units and are considered Non-SI Units.
    • These units, though not officially part of SI Units, are generally accepted for use in conjunction with SI units.
    • Apply prefixes to units and distinguish between SI and customary units

  • SI Units of Pressure

    • The SI unit of pressure is the pascal (Pa), which is equal to one Newton per meter squared (N/m2).
    • The International System of Units (abbreviated SI from the French Système International d'Unités) is the basis of the metric system.
    • The SI was established in 1960 and is based on the metre-kilogram-second system rather than the centimetre-gram-second system.
    • Derived units are unlimited in number and are formed by multiplying and dividing the seven base units and other derived units; for example, the SI derived unit of speed is meters per second, m/s.
    • The unit of pressure in the SI system is the pascal (Pa), defined as the force of one newton per square meter:

  • Standard Units (SI Units)

    • The International System of Units (abbreviated SI) is the metric system used in science, industry, and medicine.
    • The SI units of measurement have an interesting history.
    • This figure displays the fundamental SI units and the combinations that lead to more complex units of measurement.
    • Chemistry - Scientific Units the SI and Metric Units - YouTube
    • Causey teaches scientific units of the SI system, the metric system, and the CGS system.

  • Time

    • Time is the fundamental physical quantity of duration and is measured by the SI Unit known as the second.
    • Time is one of the seven fundamental physical quantities in the International System (SI) of Units.
    • Periodic events and motion have long served as standards for units of time.
    • Today, the SI Unit of the second is defined in terms of radiation emitted by cesium atoms.

  • Mass

    • The SI unit of mass is the kilogram (kg).
    • It is also the only SI unit that is directly defined by an artifact, rather than a fundamental physical property that can be reproduced in different laboratories.
    • Four of the seven base units in the SI system are defined relative to the kilogram, so the stability of this measurement is crucial for accurate and consistent measurements.
    • This value, though given in kilograms, is actually the non-SI unit of measure known as the kilogram-force.

  • Length

    • Length is a physical measurement of distance that is fundamentally measured in the SI unit of a meter.
    • Many different units of length are used around the world.
    • In the United States, the U.S. customary units operationally describe length in terms of the basic unit of an inch.
    • As such, a standard unit of measurement that is internationally accepted is needed.
    • The basic unit of length as identified by the International System of Units (SI) is the meter.

  • Converting from One Unit to Another

    • The most widely used system of units is the International System of Units, or SI.
    • There are seven SI base units, and all other SI units can be derived from these base units.
    • The seven base SI units are: [Physical Quantity: unit symbol (unit name)]
    • The base units of SI are actually not the smallest set possible; smaller sets have been defined.
    • Derived units are based on units from the SI system of units.

  • Mass

    • Mass is a physical property of matter that depends on size and shape of matter, and is expressed as kilograms by the SI system.
    • This relation is called a unit.
    • The International System of Units (SI) measures mass in kilograms, or kg.
    • There are other units of mass, including the following (only the first two are accepted by the SI system):

  • Silicate Units, Silicate Chains, Silicate Sheets

    • The basic unit of silicate, [SiO4]4- tetrahedron, can form single and double chains and sheets.
    • The basic building block of all silicate minerals is the [SiO4]4− tetrahedron.
    • There are four covalent Si−O bonds.
    • If two [SiO4]4− tetrahedrons share an oxygen atom at one common vertex, an [Si2O7]6− ion is formed.
    • SiO4 tetrahedrons can be arranged to form sheets.