Menu
Home
Explore
People
Places
Arts
History
Plants & Animals
Science
Life & Culture
Technology
Reference.org
Sign In
Science
Basics and measurement
Basics and measurement
Science basics
Science in countries
Measurement
Accuracy and precision
Closeness to true value or to each other
Acre
Unit of area
Acre-foot
Non-SI unit of volume
Aeon
Ancient Greek concept
Alcohol proof
Measure of alcohol content
Ampere
SI base unit of electric current
Ampere-hour
Unit of electric charge
Anechoic chamber
Room designed to completely absorb reflections of sound or electromagnetic waves
Angstrom
Unit of length; equals 0.1 nanometre
Apothecaries' system
Historical system of mass and volume units used by physicians and apothecaries
Approximate measures
Volumentric measurements
Astronomical system of units
System of measurement developed for use in astronomy
Astronomical unit
Mean distance between Earth and the Sun
Atomic units
System of measurement
Attosecond
One quintillionth of a second
Avoirdupois
System of weights (more properly, mass) based on a pound of 16 ounces
Bar (unit)
Unit of pressure equal to 100,000 Pa
Barleycorn (unit)
English unit of length
Barn (unit)
Unit for cross sectional area used in high-energy physics
Barrel (unit)
Unit of volume with different values
Basic research
Scientific discovery and improvement of scientific knowledge
Baud
Unit of measurement in telecommunications
Becquerel
SI derived unit of radioactivity
Biblical and Talmudic units of measurement
Units of measurement in Jewish religious texts
Biblical mile
General overview of a "biblical mile" as described in Jewish law and religion
Bismuth titanate
Chemical compound
Bit
Unit of information
Bit
Unit of information
Bit
Multiple of the unit bit
Bit
Unit of information
Bit
Unit of information
Bit
Unit of information
Bit
Unit of information
Bit
Unit of information
Bit
Unit of information
Bit
Unit of information
Bit
Unit of information
Bit
Unit of information
Bit
Unit of information
Bit
Unit of information
Bit
Unit of information
Bit
Unit of information
Blinded experiment
Experiment in which information about the test is masked to reduce bias
Branches of science
Subdivisions of science defined by their scope
British thermal unit
Unit of energy
Brix
Sugar content of an aqueous solution
Buckingham π theorem
Key theorem in dimensional analysis
Bushel
Unit of volume with numerous different definitions
Butt (unit)
Unit of volume with different values
Byte
Unit of digital information, usually 8 bits
Byte (magazine)
Defunct American microcomputer magazine
Cable length
Unit of length
Calorie
Unit of energy used in nutrition
Candela
SI unit of luminous intensity
Candlepower
Unit of measurement
Carucate
Medieval land unit from England and Scotland
Case study
Intensive analysis of an individual unit stressing developmental factors in relation to context
Celsius
Scale and unit of measurement for temperature
Centimetre
Unit of length
Centimetre–gram–second system of units
Physical system of measurement that uses the centimetre, gram, and second as base units
Century
Unit of time lasting 100 years
Chain (unit)
Unit of length
Chronometry
Specifying measures of time-mesaurement in clear reference units
Cleanroom
Room which is used for industrial or research processes that do not tolerate dust
Cologne mark
European unit of mass, equal to approximately 233.856 grams
Comparison of the imperial and US customary measurement systems
Comparison
Complex system
System composed of many interacting components
Computational science
Field that uses computers and mathematical models to analyze and solve scientific problems
Conversion of units
Comparison of various scales
Cooking weights and measures
List article
Cord (unit)
Unit of volume of wood
Cubic centimetre
Unit of volume
Cubic foot
Imperial and US customary (non-metric) unit of volume
Cubic inch
Unit of volume
Cubic metre
SI derived unit of volume
Cubic metre per second
SI unit of volumetric flow rate
Cubic mile
Rarely used unit of volume
Cubic yard
Imperial / U.S. customary unit of volume
CUBIT
Multi-touch interface
Cup (unit)
Cooking measure of volume
Curie (unit)
Non-SI unit of radioactivity
Cybernetics
Study of regulatory and purposive systems
Dalton (unit)
Standard unit of mass for atomic-scale chemical species
DATA
Organization
Data analysis
A process of inspecting, cleansing, transforming and modeling data
Data science
Field of study to extract knowledge from data
Data sharing
Practice of making data available to others
Day
Unit of time
Day's journey
Nonstandard measurement of distance
Decade
Period of 10 years
Decibel
Logarithmic unit expressing the ratio of a physical quantity
Degree (angle)
Angle unit; π/180 radians
Dessert spoon
Spoon designed specifically for eating dessert
Digit (unit)
Unit of length
Dimensional analysis
Analysis of the relationships between different physical quantities
Dozen
Group of twelve items
Dram (unit)
Unit of mass or volume in different systems
Drop (unit)
Unit of measure of volume used when dispensing drugs
Dry measure
Unit of volume for things which are not fluids
Dyne
Unit of force
Earth mass
Unit of mass equal to that of Earth
Electron
Subatomic particle with negative electric charge (−1)
Electronvolt
Unit of energy
Ell
Unit of length
English brewery cask units
Traditional English volume measurement units for beer
English units
System of units formerly used in England
English wine cask units
Traditional volume measurement units for wine
English wine cask units
Traditional volume measurement units for wine
Environmental science
The integrated, quantitative, and interdisciplinary approach to the study of environmental systems.
Enzyme unit
Unit of catalytic activity; one micromole per minute; 16.66… nanokatals
Epoch
Reference point from which time is measured
Era
Span of time that defined for the purposes of chronology or historiography
Erg
Unit of energy and mechanical work
Eternity
Endless time, an infinite duration
Experiment
Scientific procedure performed to validate a hypothesis
Fahrenheit
Temperature scale
Farad
SI unit of electric capacitance
Fathom
Unit of length in the old imperial and the U.S. customary systems
Femtometre
Unit of length
Femtosecond
One quadrillionth of a second
Field research
Collection of information outside a laboratory, library or workplace setting
Fieldnotes
Notes recorded by researchers in the course of field research
Finger (unit)
Unit of length
Flick (time)
Unit of time used in audio/video timing cacluations
Fluid ounce
Set of units of volume
Foot (unit)
Customary unit of length
Foot per second
Unit of speed
Foot-pound (energy)
Unit of energy
Foot–pound–second system of units
Physical system of measurement that uses the foot, pound, and second as base units
Formal science
Branch of science
Fortnight
Time period of two weeks
Fringe science
Inquiries far outside of mainstream science
Funding of science
Mechanisms of allocating financial resources to research
Furlong
Unit of length equal to 660 feet or about 201 metres
Gal (unit)
Centimeter–gram–second unit of acceleration
Gallon
Units of volume
Gauss (unit)
Unit of magnetic induction
Gaussian units
Variant of the centimetre–gram–second unit system
Geometrized unit system
System of units in which the gravitational constant and the velocity of light are treated as unity
Gigabyte
Unit of information
Gill (unit)
Unit of volume with different values
Gradian
Unit of measurement of an angle, equal to 1/400th of a circle
Grain (unit)
Unit of mass
Gram per cubic centimetre
SI unit of density
Gramin Agriculture Markets
Gravitational metric system
System with base units kilopond, metre and second
Gray (unit)
SI derived unit of absorbed dose of ionizing radiation
Gross (unit)
Group of 144; a dozen dozen
Hand (unit)
Unit of length
Hartree
Atomic unit of energy
Heaviside–Lorentz units
System of electromagnetic units
Hectare
Metric unit of area
Height above mean sea level
Elevation of a location above a standardized sea level
Henry (unit)
SI unit of inductance
Hertz
SI unit for frequency
Hide (unit)
Historical unit of land measurement
Hogshead
Unit of volume
Horsepower
Unit of power with different values
Hour
Unit of time equal to 60 minutes
Hundred (county division)
Geographical administrative division
Hundredweight
Unit of weight or mass, with differing values
Imperial and US customary measurement systems
English (pre 1824), Imperial (post 1824) and US Customary (post 1776) units of measure
Imperial units
System of units that were implemented on 1 January 1826 in the British Empire
Imperial units
System of units that were implemented on 1 January 1826 in the British Empire
Inch
Unit of length
International System of Quantities
System of quantities used in science and their interrelationships
International System of Units
Modern form of the metric system
International System of Units
Modern form of the metric system
International yard and pound
Units defined by international agreement
Inverse second
SI unit of reciprocal duration
Jansky
Unit of spectral flux density (radio astronomy); 0.01 yoctowatt per square metre hertz
Joule
SI unit of energy
Joule-second
SI unit of action
Jupiter mass
Mass of planet Jupiter, used as unit of weight
Katal
SI derived unit of catalytic activity
Kelvin
SI unit of temperature
Kilobyte
Multiple of the unit byte
Kilogram
Metric unit of mass
Kilogram per cubic metre
SI derived unit of density
Kilogram-force
Unit of force in gravitational metric system; weight of one kilogram of mass in standard Earth gravity
Kilometre
Unit of length equal to 1,000 metres
Kilometres per hour
Unit of speed
Kilowatt-hour
Unit of energy
Knight's fee
Feudal unit measure of land
Knot (unit)
Unit of speed
Laboratory
Facility that provides controlled conditions in which scientific or technological research, experiments, and measurement may be performed.
Laboratory glassware
Variety of equipment, traditionally made of glass, used for scientific experiments and other work in science, especially in chemistry and biology laboratories
Laboratory safety
Risks and prevention of laboratory accidents
League (unit)
Unit of length
Light-year
Unit of length, the distance that light travels in one year; ~10^13 km
Line (unit)
English unit of length
Link (unit)
Unit of length
Litre
Unit of volume
Long ton
Unit of mass used in many Commonwealth countries and the United States
Lot (weight)
Unit of mass
Lumen (unit)
SI derived unit of luminous flux
Lunar distance
Distance from center of Earth to center of Moon
Lustrum
Unit of time, usually a five year period
LUX
Gene of the species Arabidopsis thaliana
Mark (unit)
Unit of mass for gold and silver
Mass fraction (chemistry)
Fraction of one substance's mass to the mass of the total mixture
Maxwell (unit)
Compound derived CGS unit of magnetic flux; equals 10 nanowebers
Measurement
Process of assigning numbers to objects or events
Medical laboratory
Laboratory where tests are carried out on patients' or clients' or subjects' specimens to obtain information about the health status of the affected individuals to aid in diagnosis, treatment, research and prevention of disease
Megabyte
Multiple of the unit byte
Metre
SI unit of length
Metre per second
SI derived unit of speed and velocity
Metre per second squared
SI derived unit of acceleration
Metre–tonne–second system of units
System of physical units
Metric system
Metre-based systems of measurement
Metrology
Science of measurement and its application
Microgram
Unit of mass, 1 millionth of a gram
Micrometre
Unit of Length: one millionth of a metre
Microsecond
One millionth of a second
Mile
Unit of length
Miles per hour
Unit of speed
Millennium
Time period of 1000 years
Millimetre
Unit of length 1/1000 of a metre
Millimetre of mercury
Manometric unit of pressure
Milliradian
Angular measurement, thousandth of a radian
Millisecond
One thousandth of a second
Minim (unit)
Unit of volume
Minute
Unit of time equal to 60 seconds
Minute and second of arc
Units for measuring angles
MKS units
Physical system of measurement that uses the metre, kilogram, and second as base units
Molality
Amount of substance of solute divided by the mass of the solvent
Molar concentration
Measure of the concentration of a solute in a solution, or of any chemical species, in terms of amount of substance in a given volume; most commonly expressed in units of moles of solute per litre of solution
Mole (unit)
SI unit of amount of substance
Mole fraction
The proportion of a constituent to the total amount of all constituents in a mixture, expressed in mol/mol
Moment (unit)
Medieval unit of time
Month
Unit of time
Nail (unit)
Unit of cloth measurement
Nanometre
Unit of length
Nanosecond
Unit of time
Nat (unit)
Logarithmic unit of information
Natural environment
All living and non-living things occurring naturally, generally on Earth
Natural science
Branch of science about the natural world
Natural units
Units of measurement based on universal physical constants
Nature
Natural, physical, or material world and its phenomena
Nautical mile
Unit of distance (1852 m)
Neper
Logarithmic unit for ratios of measurements of physical field and power quantities
Newton (unit)
Unit of force in physics
Newton-metre
SI unit of torque
Newton-second
SI derived unit of impulse
Observation
Active acquisition of information from a primary source
Ohm
SI derived unit of electrical resistance
Olympiad
Period of four years associated with the Olympic Games of the Ancient Greeks
Ounce
Unit of mass
Oxgang
Old English and Scottisch land measurement
Palm (unit)
Anthropic unit of length, based on the width of the human palm and then variously standardized
PARSEC
Software package for performing electronic structure calculations of solids and molecules using density functional theory
Pascal (unit)
SI derived unit of pressure
Peck
Unit of volume with different values
Peer review
Evaluation of work by one or more people of similar competence to the producers of the work
Pennyweight
Unit of mass
Perm (unit)
Unit of permeance
Pica (typography)
Unit of length
Picometre
Unit of length (10^-12 meters)
Picosecond
One trillionth of a second
Pinch (unit)
Amount that can be taken between the thumb and forefinger
Pint
Unit of volume in the imperial and US systems
Planck units
Units defined only by physical constants
Point (typography)
Measurement unit used in typography
Poise (unit)
CGS unit of dynamic viscosity equal to 1 g/(cm·s)
Pound (force)
Unit in some systems of measurement
Pound (mass)
Unit of mass
Pound per square inch
Unit of pressure or stress
Pound sterling
Unit of account in Anglo-Saxon England
Puncheon (unit)
Unit of volume
Qualitative Research (journal)
Academic journal
Quantitative research
All procedures for the numerical representation of empirical facts
Quart
Unit of volume with different values
Rad (radiation unit)
Non-SI unit measuring absorbed dose of ionizing radiation
Radian
SI derived unit of angle
Radian per second
SI unit of angular velocity or angular frequency
Rankine scale
Absolute temperature scale using Fahrenheit degrees
Relative density
Ratio of the density (mass per volume) of a substance to the density of a given reference material
Reproducibility
Agreement with previous measurements using the same methodology in the same context
Research
Systematic study undertaken to increase knowledge
Revolutions per minute
Number of rotations around a fixed axis in one minute
Reyn
Unit of dynamic viscosity
Rod (unit)
Unit of length
Roentgen (unit)
Legacy unit of measurement for the kerma of X-rays and gamma rays up to 3 MeV; equals 0.258 mC/kg
Rood (unit)
English unit of length or area
Rundlet
Sack (unit)
Traditional unit of mass or volume
Sarpler
Scholarly peer review
Subjecting an author's work or research to scrutiny
Science (disambiguation)
Topics referred to by the same term
Science and technology in Brazil
Overview of science and technology in Brazil
Science and technology in China
Science and technology in Europe
Overview of science and technology in Europe
Science and technology in France
Overview of science and technology in France
Science and technology in Germany
Overview of Germany's handling with science and technology
Science and technology in India
Science and technology in Israel
National research, development and proficience
Science and technology in Italy
Overview of science and technology in Italy
Science and technology in Japan
Overview of science and technology in Japan
Science and technology in Russia
Overview of science and technology in Russia
Science and technology in South Korea
Overview of science and technology in South Korea
Science and technology in the Soviet Union
Overview of the role of science and technology in the Soviet Union
Science and technology in the United Kingdom
Overview of science and technology in the United Kingdom
Science and technology in the United States
National integration of science and technology
Scientific community
Network of interacting scientists
Scientific evidence
Evidence that either supports or counters a scientific theory
Scientific law
Statement based on repeated empirical observations that describes some natural phenomenon
Scientific method
Interplay between observation, experiment and theory in science
Scientific misconduct
Violation of codes of scholarly conduct and ethical behavior in scientific research
Scientific modelling
Scientific activity that produces models
Scientific theory
Explanation of some aspect of the natural world which can be tested and verified
Scientist
Person who conducts scientific research
Second
SI unit of time
Shaftment
Obsolete unit of measurement
Shake (unit)
Informal unit of time equal to 10 nanoseconds
Shannon (unit)
Unit of information
Short ton
Unit of mass
Siemens (unit)
SI unit of electric conductance
Sievert
SI unit of equivalent dose of ionizing radiation
Slug (unit)
Unit of mass
Solar luminosity
Unit of light in stars and galaxies
Solar mass
Standard unit of mass in astronomy
Solar radius
Unit of measurement
Span (unit)
Unit of length
Square degree
Unit of solid angle; (π/180)² steradians
Square foot
Imperial unit and U.S. customary unit of area
Square inch
Unit of area
Square kilometre
Unit of area
Square metre
SI-derived unit of area
Square mile (disambiguation)
Topics referred to by the same term
Square yard
Unit of area
Stadion (unit)
Ancient Greek unit of length
Standard atmosphere (unit)
Unit of pressure defined as 101325 Pa
Standard gravity
Standard gravitational acceleration on Earth
Statcoulomb
CGS unit of electric charge
Steradian
SI derived unit of solid angle
Stere
Metric unit of volume defined as one cubic metre (1 m³) of stacked firewood
Stone (unit)
Unit of measure equal to 14 pounds avoirdupois
Stoney units
System of natural units
System
Interrelated entities that form a whole
System of units of measurement
Collection of units of measurement and rules relating them to each other
Tablespoon
Kind of spoon and unit of volume
Teaspoon
Kind of spoon
Telemetry
Data and measurements transferred from a remote location to receiving equipment for monitoring
Tesla (unit)
SI unit of magnetic field strength
Tierce (unit)
TNT equivalent
Class of units of measurement for explosive energy
Ton (disambiguation)
Topics referred to by the same term
Tonne
Metric unit of mass equivalent to 1,000 kilograms
Torr
Traditional unit of pressure
Troy weight
System of units of mass
Tun (unit)
English unit of liquid volume
UA4 experiment
Particle physics experiment at CERN
Unit of account
Money function
Unit of measurement
Definite magnitude of a quantity, defined and adopted by convention or by law, that is used as a standard for measurement of the same kind of quantity
United States customary units
System of units of measurement commonly used in the United States
Units of information
Capacity of information storage and communication
Virgate
English unit of land
Volt
SI derived unit of voltage
Volume fraction
Dimensionless quantity
WATT
Radio station in Cadillac, Michigan
Weber (unit)
SI derived unit of magnetic flux
Week (disambiguation)
Topics referred to by the same term
Winchester measure
Set of legal standards of volume instituted in the late 15th century (1495) by King Henry VII of England
Yard
Unit of length
Year
Recurrent cycle of significant duration