Scientific units are standard quantities used to measure and describe the physical properties of matter and phenomena in the universe. They provide a consistent way to express measurements clearly and accurately, so that scientists and people around the world can easily communicate. Scientific units are part of the International System of Units (SI), which is based on the metric system. This system includes units for measuring length, mass, time, electric current, temperature, amount of substance, and light intensity.
The basic unit of length is meter (m), which measures distance. Kilogram (kg) is used for mass, which measures the amount of matter in an object. Time is measured in seconds (s), which helps us measure periods and intervals. Electric current is measured in amperes (A), which indicates the flow of electric charge. Temperature is measured in Kelvin (K), which measures how hot or cold an object is. Mole is used for the amount of substance, which helps in counting particles like atoms or molecules. Light intensity, which is the brightness of a light source, is measured in candela (cd).
Apart from these basic units, there are also derived units, which are formed by combination of basic units. For example, the unit of speed is meters per second (m/s), which combines length and time. The unit of force is the newton (N), which combines mass, length, and time (kg·m/s²).
Scientific units are important because they ensure that everyone uses the same standards, making it easier to compare and reproduce results. Without standard units, communication and collaboration in science and engineering would become much more difficult, leading to confusion and errors. The consistent use of scientific units enables advancements in technology, medicine, engineering, and many other fields, providing a common language for scientists and professionals. In this article we tell us about list of scientific units.
SI Base Units
| SI Base Unit | Symbol | Quantity | Named After |
|---|---|---|---|
| Ampere | A | Electric current | André-Marie Ampère |
| Kelvin | K | Thermodynamic temperature | Lord Kelvin (William Thomson) |
SI Derived Units
| SI Derived Unit | Quantity | Named After |
|---|---|---|
| Becquerel (Bq) | Radioactivity | Henri Becquerel |
| Degree Celsius (°C) | Temperature | Anders Celsius |
| Coulomb (C) | Electric charge | Charles-Augustin de Coulomb |
| Farad (F) | Capacitance | Michael Faraday |
| Gray (Gy) | Absorbed dose of radiation | Louis Harold Gray |
| Henry (H) | Inductance | Joseph Henry |
| Hertz (Hz) | Frequency | Heinrich Rudolf Hertz |
| Joule (J) | Energy, work, heat | James Prescott Joule |
| Newton (N) | Force | Isaac Newton |
| Ohm (Ω) | Electrical resistance | Georg Ohm |
| Pascal (Pa) | Pressure | Blaise Pascal |
| Siemens (S) | Electrical conductance | Werner von Siemens |
| Sievert (Sv) | Radiation dose equivalent | Rolf Sievert |
| Tesla (T) | Magnetic flux density | Nikola Tesla |
| Volt (V) | Electric potential, electromotive force | Alessandro Volta |
| Watt (W) | Power, radiant flux | James Watt |
| Weber (Wb) | Magnetic flux | Wilhelm Eduard Weber |
Centimetre–Gram–Second System of Units
| Unit | Symbol | Quantity | Named After |
|---|---|---|---|
| Biot | Bi | Electric current | Jean-Baptiste Biot |
| Buckingham | B | Electric quadrupole moment | A. David Buckingham |
| Debye | D | Electric dipole moment | Peter Debye |
| Eotvos | E | Gravitational gradient | Loránd Eötvös |
| Galileo | Gal | Acceleration | Galileo Galilei |
| Gauss | G or Gs | Magnetic flux density | Carl Friedrich Gauss |
| Gilbert | Gb | Magnetomotive force | William Gilbert |
| Goeppert-Mayer | GM | Two-photon absorption cross-section | Maria Goeppert-Mayer |
| Kayser | kayser | Wavenumber | Heinrich Kayser |
| Maxwell | Mx | Magnetic flux | James Clerk Maxwell |
| Oersted | Oe | Magnetic field strength | Hans Christian Ørsted |
| Poise | P | Dynamic viscosity | Jean Léonard Marie Poiseuille |
| Rayl or Rayleigh | Rayl | Acoustic impedance | John William Strutt, 3rd Baron Rayleigh |
| Rayleigh | R | Photon flux | Robert John Strutt, 4th Baron Rayleigh |
| Stokes | S or St | Kinematic viscosity | George Gabriel Stokes |
No More Longer in Use
| Name | Symbol | Quantity | Named After |
|---|---|---|---|
| Franklin | Fr | Electric Charge | Benjamin Franklin |
| Clausius | Cl | Entropy | Rudolf Clausius |
Other Scientific Units
| Name | Symbol | Quantity | Named After |
|---|---|---|---|
| Ångström | Å | Distance | Anders Jonas Ångström |
| Baud | Bd | Symbol Rate | Emile Baudot |
| Bark Scale | Psychoacoustical Scale | Heinrich Barkhausen | |
| Brewster | B | Stress Optic Coefficient | David Brewster |
| Centimorgan | cM | Recombination Frequency | Thomas Hunt Morgan |
| Curie | Ci | Radioactivity | Marie and Pierre Curie |
| Dalton | Da | Atomic Mass | John Dalton |
| Darcy | D | Permeability | Henry Darcy |
| Decibel | dB | Dimensionless Proportions and Ratios | Alexander Graham Bell |
| Degree Fahrenheit | °F | Temperature | Daniel Gabriel Fahrenheit |
| Degree Rankine | °R | Temperature | William John Macquorn Rankine |
| Dobson Unit | DU | Atmospheric Ozone | Gordon Dobson |
| Erlang | E | Dimensionless Volume of Telecommunications Traffic | Agner Krarup Erlang |
| Fermi | fm | Distance | Enrico Fermi |
| Hartley | Hart | Information | Ralph Hartley |
| Hounsfield Scale | Radiodensity | Godfrey Newbold Hounsfield | |
| Jansky | Jy | Electromagnetic Flux | Karl Jansky |
| Langley | ly | Solar Radiation | Samuel Pierpont Langley |
| Langmuir | L | Gas Exposure Dose | Irving Langmuir |
| Mach Number | Ma | Relative Speed | Ernst Mach |
| Neper | Np | Relative Power Level | John Napier |
| Degree Öchsle | °Oe | Density | Ferdinand Öchsle |
| Rockwell Scale | HR | Indentation Hardness | Stanley Rockwell |
| Röntgen | R | Dosage of X-rays or Gamma Radiation | Wilhelm Röntgen |
| Richter Magnitude | Earthquake Power | Charles Francis Richter | |
| Scoville Units | Capsaicin Content of Chili Peppers | Wilbur Scoville | |
| Shannon | Sh | Information | Claude Shannon |
| Siegbahn | xu | Distance | Manne Siegbahn |
| Svedberg | S or Sv | Sedimentation Rate | Theodor Svedberg |
| Sverdrup | Sv | Volume Transport Rate | Harald Sverdrup |
| Torr | Torr | Pressure | Evangelista Torricelli |
| Troland | Td | Luminance (Human Eye) | Leonard Troland |
Natural Scientific Unit Systems
| Parameter | Planck Units | Stoney Units |
|---|---|---|
| Length | Planck length (ℓP) | Stoney length (ℓS) |
| Mass | Planck mass (mP) | Stoney mass (mS) |
| Time | Planck time (tP) | Stoney time (tS) |
| Electric Charge | Planck charge (qP) | Stoney charge (qS) |
| Electric Current | Planck current (IP) | Stoney current (IS) |
| Temperature | Planck temperature (TP) | Stoney temperature (TS) |
| Energy | Planck energy (EP) | Stoney energy (ES) |
| Force | Planck force (FP) | Stoney force (FS) |
Scientific Units That No Longer in Use
| No Longer in Use | Field | Inventor/Originator |
|---|---|---|
| Mercalli Intensity Scale | Earthquake Effects | Giuseppe Mercalli |
| Degree Réaumur (°R) | Temperature | René Antoine Ferchault de Réaumur |
| Degree Delisle (°D) | Temperature | Joseph-Nicolas Delisle |
| Degree Newton (°N) | Temperature | Isaac Newton |
| Degree Rømer (°Rø) | Temperature | Ole Rømer |
| Degree Baumé (°Bé) | Density | Antoine Baumé |
| Einstein (E) | Photochemistry | Albert Einstein |
| Poncelet (p) | Power | Jean-Victor Poncelet |
| Faraday (Fd) | Electrical Charge | Michael Faraday |