Metrology
27 entries in the Metrology compendium.
MetrologyThe science of measurement, essential for trade and society.International System of QuantitiesStandard system of quantities underlying the International System of Units.International Prototype of the KilogramThe International Prototype of the Kilogram (IPK), known to metrologists as Le Grand K or,Caesium standardThe caesium standard is a primary frequency standard that works by using the absorption ofCoherence (units of measurement)Coherent units eliminate conversion factors in derived definitions.Conversion of unitsTechnique for changing units using multiplicative conversion factors.Dimensional analysisMethod for analyzing physical dimensions of quantities.Buckingham pi theoremTheorem restating physical equations using dimensionless parameters.Comparison of the imperial and US customary measurement systemsTwo measurement systems with a common origin but distinct differences.Imperial and US customary measurement systemsTwo related systems of measurement derived from English units.English units of measurementEnglish units preceded Imperial and US customary systems.International yard and poundAgreement defining yard and pound in metric terms.Centimetre–gram–second system of unitsMetric system variant using centimetre, gram, and second.Foot–pound–second system of unitsA system of units based on foot, pound, and second.MKS unitsCoherent measurement system that evolved into the International System of Units.Geometrized unit systemA unit system setting c and G to unity for relativity.Heaviside–Lorentz unitsRationalized CGS-based units eliminating 4π from Maxwell's equations.Atomic unitsA natural unit system for atomic physics calculations.Astronomical system of unitsA conventional system for astronomical measurement, adopted by the IAU.Apothecaries' systemHistorical medical weight and volume system used by apothecaries.Biblical and Talmudic units of measurementAncient Israelite measurement system still used in Orthodox Jewish law.Chinese units of measurementTraditional Han Chinese measurement system, still used in modified forms.Japanese units of measurementTraditional Japanese measurement system still used in carpentry and agriculture.Korean units of measurementTraditional Korean system of measurement, still used informally.Cooking weights and measuresSystems for specifying ingredient quantities vary by region and era.AvoirdupoisAvoirdupois (abbreviated avdp.) is a weight measurement system built around pounds and ounApproximate measuresUnofficial volumetric units with inconsistent, historically derived values.
Browse Metrology in the interactive codex →