List of recognized physical constants:

• "earth radius" (6371.00 km)
• "earth's radius" (6371.00 km)
• "moon radius" (1737.5 km)
• "moon's radius" (1737.5 km)
• "sun radius" (696340 km)
• "sun's radius" (696340 km)
• "sun mass" (1.9885e30 kg)
• "sun's mass" (1.9885e30 kg)
• "earth mass" (5.972e24 kg)
• "earth's mass" (5.972e24 kg)
• "moon mass" (7.342e22 kg)
• "moon's mass" (7.342e22 kg)
• "earth gravitational constant" (9.807 m/s^2)
• "earth's gravitational constant" (9.807 m/s^2)
• "moon gravitational constant" (1.625 m/s^2)
• "moon's gravitational constant" (1.625 m/s^2)
• "sun gravitational constant" (274 m/s^2)
• "sun's gravitational constant" (274 m/s^2)
• "earth density" (5514 kg/m^3)
• "earth's density" (5514 kg/m^3)
• "moon density" (3340 kg/m^3)
• "moon's density" (3340 kg/m^3)
• "sun density" (1408 kg/m^3)
• "sun's density" (1408 kg/m^3)
• "earth surface area" (510.1 million km^2)
• "earth's surface area" (510.1 million km^2)
• "moon surface area" (37.9 million km^2)
• "moon's surface area" (37.9 million km^2)
• "sun surface area" (6.09 billion km^2)
• "sun's surface area" (6.09 billion km^2)
• "earth volume" (1.08321e12 km^3)
• "earth's volume" (1.08321e12 km^3)
• "moon volume" (2.1958e10 km^3)
• "moon's volume" (2.1958e10 km^3)
• "sun volume" (1.412e18 km^3)
• "sun's volume" (1.412e18 km^3)
• "planck constant" (6.62607015e-34 J*s)
• "planck's constant" (6.62607015e-34 J*s)
• "gravitational constant" (6.67430e-11 m^3/kg*s^2)
• "universal gravitational constant" (6.67430e-11 m^3/kg*s^2)
• "boltzmann constant" (1.380649e-23 J/K)
• "boltzmann's constant" (1.380649e-23 J/K)
• "avogadro number" (6.02214076e23 mol^-1)
• "avogadro's number" (6.02214076e23 mol^-1)
• "fine structure constant" (7.2973525693e-3)
• "fine-structure constant" (7.2973525693e-3)
• "stefan-boltzmann constant" (5.670374419e-8 W/m^2*K^4)
• "stefan-boltzmann's constant" (5.670374419e-8 W/m^2*K^4)
• "rydberg constant" (10973731.568160 m^-1)
• "rydberg's constant" (10973731.568160 m^-1)
• "electron charge" (1.602176634e-19 C)
• "permittivity of free space" (8.854187817e-12 F/m)
• "vacuum permeability" (1.25663706212e-6 H/m)
• "permeability of free space" (1.2566370614e-6 H/m)
• "atomic mass constant" (1.66053906660e-27 kg)
• "faraday's constant" (96485.33212 C/mol)
• "faraday constant" (96485.33212 C/mol)
• "gas constant" (8.314462618 J/(mol*K))
• "universal gas constant" (8.314462618 J/(mol*K))
• "molar volume of ideal gas (273.15 K, 1 atm)" (22.41396954 L/mol)
• "standard molar volume" (22.41396954 L/mol)
• "wiens displacement constant" (2.897771955e-3 m*K)
• "wiens law constant" (2.897771955e-3 m*K)
• "speed of sound in air at sea level" (343 m/s)
• "speed of sound at sea level" (343 m/s)
• "magnetic flux quantum" (2.067833848e-15 Wb)
• "quantum of magnetic flux" (2.067833848e-15 Wb)
• "luminous efficacy of a monochromatic radiation of 540 THz" (683 lm/W)
• "luminous efficacy at 540 THz" (683 lm/W)
• "cosmological constant" (1.1e-52 m^-2)
• "einstein's cosmological constant" (1.1e-52 m^-2)
• "einstein cosmological constant" (1.1e-52 m^-2)
• "solar luminosity" (3.828e26 watts)
• "luminosity of the sun" (3.828e26 watts)
• "earth's albedo" (0.306)
• "earth albedo" (0.306)
• "albedo of earth" (0.306)
• "earth's escape velocity" (11.186 km/s)
• "earth escape velocity" (11.186 km/s)
• "escape velocity of earth" (11.186 km/s)
• "solar constant" (1367 W/m^2)
• "average solar irradiance" (1361 W/m^2)
• "mean earth orbital speed" (29.78 km/s)
• "average speed of earth around sun" (29.78 km/s)
• "standard atmospheric pressure" (101325 Pa)
• "joule's constant" (4.184 J/cal)
• "joule constant" (4.184 J/cal)
• "mechanical equivalent of heat" (4.184 J/cal)
• "coulomb's constant" (8.9875517873681764e9 N*m^2/C^2)
• "coulomb constant" (8.9875517873681764e9 N*m^2/C^2)
• "electric force constant" (8.9875517873681764e9 N*m^2/C^2)
• "bohr magneton" (9.2740100783e-24 J/T)
• "bohr's magneton" (9.2740100783e-24 J/T)
• "nuclear magneton" (5.0507837461e-27 J/T)
• "nuclear's magneton" (5.0507837461e-27 J/T)
• "earth's angular velocity" (7.27220521664304e-5 rad/s)
• "earth angular velocity" (7.27220521664304e-5 rad/s)
• "angular velocity of earth" (7.27220521664304e-5 rad/s)
• "earth's orbital eccentricity" (0.0167)
• "earth orbital eccentricity" (0.0167)
• "orbital eccentricity of earth" (0.0167)
• "pi constant" (3.141592653589793238462643383)
• "golden ratio" (1.618033988749895)
• "phi constant" (1.618033988749895)
• "distance light travels in one year" (9.4607e12 km)
• "distance from earth to sun" (149597870.7 km)
• "distance measurement in astronomy" (3.085677581491367e13 km)
• "earth age" (4.543 billion years)
• "age of earth" (4.543 billion years)
• "universe age" (13.8 billion years)
• "age of the universe" (13.8 billion years)
• "earth circumference" (40075 km)
• "circumference of earth" (40075 km)
• "energy unit" (1.602176634e-19 J)
• "earth's magnetic dipole moment" (7.79e22 A*m^2)
• "earth magnetic dipole moment" (7.79e22 A*m^2)
• "magnetic dipole moment of earth" (7.79e22 A*m^2)
• "molar mass constant" (12 g/mol)
• "maxwell's equations constant" (8.9875517873681764e9 N*m^2/C^2)
• "maxwell equations constant" (8.9875517873681764e9 N*m^2/C^2)
• "electric constant" (8.854187817e-12 F/m)
• "schwarzschild radius of the sun" (2953 m)
• "schwarzschild radius" (2953 m)
• "thermal conductivity of copper" (401 W/m*K)
• "thermal conductivity" (401 W/m*K)
• "viscosity of water at 20 C" (0.001002 Pa*s)
• "dynamic viscosity of water" (0.001002 Pa*s)
• "young's modulus of steel" (210 GPa)
• "young modulus of steel" (210 GPa)
• "young's modulus" (210 GPa)
• "young modulus" (210 GPa)
• "surface tension of water at 25 C" (0.07275 N/m)
• "surface tension" (0.07275 N/m)
• "heat capacity of water at constant pressure" (4182 J/kg*K)
• "specific heat capacity of water" (4182 J/kg*K)
• "melting point of iron" (1538 celsius)
• "melting temperature of iron" (1538 celsius)
• "boiling point of water at 1 atm" (100 celsius)
• "boiling temperature of water" (100 celsius)
• "density of mercury" (13534 kg/m^3)
• "density" (13534 kg/m^3)
• "speed of sound in water at 25 C" (1493 m/s)
• "speed of sound in water" (1493 m/s)
• "refractive index of air" (1.000277)
• "refraction index" (1.000277)
• "thermal expansion coefficient of aluminum" (23.1e-6 /celsius)
• "coefficient of thermal expansion for aluminum" (23.1e-6 /celsius)
• "dielectric constant of vacuum" (1)
• "vacuum dielectric constant" (1)
• "specific gravity of gold" (19.32)
• "density of gold" (19320 kg/m^3)
• "magnetic susceptibility of copper" (-9.2e-6)
• "copper magnetic susceptibility" (-9.2e-6)
• "mohs hardness of diamond" (10)
• "diamond mohs hardness" (10)
• "mohs hardness of quartz" (7)
• "quartz mohs hardness" (7)
• "heat of fusion of ice" (334 J/g)
• "latent heat of fusion for ice" (334 J/g)
• "solar irradiance at earth" (1367 W/m^2)
• "capacitance of Earth" (710 microfarads)
• "earth capacitance" (710 microfarads)
• "stefan-boltzmann law constant" (5.670374419e-8 W/m^2*K^4)
• "magnetic constant" (1.2566370614e-6 H/m)
• "absolute zero temperature" (-273.15 celsius)
• "absolute zero" (-273.15 celsius)
• "critical point of water" (374 celsius, 22.064 MPa)
• "water critical temperature and pressure" (374 celsius, 22.064 MPa)
• "viscosity of air at 20 C" (0.0181 mPa*s)
• "air viscosity" (0.0181 mPa*s)
• "heat of vaporization of water at 100 C" (2260 J/g)
• "latent heat of vaporization for water" (2260 J/g)
• "compressibility of water at 25 C" (4.6e-10 Pa^-1)
• "water compressibility" (4.6e-10 Pa^-1)
• "conductivity of silver" (63*10^6 S/m)
• "electrical conductivity of silver" (63*10^6 S/m)
• "ionization energy of hydrogen" (13.5984 eV)
• "hydrogen ionization potential" (13.5984 eV)
• "optical fiber index of refraction" (1.44)
• "refractive index of optical fiber" (1.44)
• "yield strength of structural steel" (250 MPa)
• "structural steel yield strength" (250 MPa)
• "density of air at sea level" (1.225 kg/m^3)
• "air density at sea level" (1.225 kg/m^3)
• "photon energy of red light (650 nm)" (1.91 eV)
• "energy of red light photon" (1.91 eV)
• "earth gravitational pull" (9.80665 m/s^2)
• "coefficient of friction for ice on ice" (0.1)
• "ice-on-ice friction coefficient" (0.1)
• "caloric value of coal" (24 MJ/kg)
• "energy density of coal" (24 MJ/kg)
• "luminosity of a typical star" (3.846e26 W)
• "typical stellar luminosity" (3.846e26 W)
• "radius of a typical neutron star" (10 km)
• "neutron star typical radius" (10 km)
• "average density of the universe" (9.9e-27 kg/m^3)
• "universe density" (9.9e-27 kg/m^3)
• "heat capacity of nitrogen at 25 C" (1040 J/kg*K)
• "specific heat capacity of nitrogen" (1040 J/kg*K)
• "melting point of tungsten" (3422 celsius)
• "tungsten melting temperature" (3422 celsius)
• "boiling point of nitrogen" (-196 celsius)
• "nitrogen boiling temperature" (-196 celsius)
• "speed of light in glass" (200000 km/s)
• "light speed in glass" (200000 km/s)
• "average lifespan of a red dwarf star" (100 billion years)
• "red dwarf star lifespan" (100 billion years)
• "Milky Way mass" (1.5 trillion solar masses)
• "charge of a proton" (1.602176634e-19 C)
• "proton charge" (1.602176634e-19 C)
• "diffusion coefficient of oxygen in air" (0.178 cm^2/s)
• "oxygen diffusion rate in air" (0.178 cm^2/s)
• "electrical resistivity of silver" (1.59e-8 ohm*m)
• "silver resistivity" (1.59e-8 ohm*m)
• "solar radius to earth radius ratio" (109.2)
• "surface gravity of Jupiter" (24.79 m/s^2)
• "Jupiter's gravitational pull" (24.79 m/s^2)
• "Jupiter gravitational pull" (24.79 m/s^2)
• "thermal conductivity of diamond" (2200 W/m*K)
• "diamond thermal conductivity" (2200 W/m*K)
• "uranium-238 half-life" (4.468 billion years)
• "energy yield of TNT" (4.184 MJ/kg)
• "TNT energy density" (4.184 MJ/kg)
• "viscosity of glycerol at 20 C" (1.412 Pa*s)
• "glycerol viscosity" (1.412 Pa*s)
• "capillary rise of water in a 1 mm diameter tube" (14.5 mm)
• "water capillary action in 1 mm tube" (14.5 mm)
• "diameter of Milky Way" (105,700 light years)
• "Milky Way diameter" (105,700 light years)
• "photon energy of blue light (475 nm)" (2.62 eV)
• "energy of blue light photon" (2.62 eV)
• "atomic radius of hydrogen" (53 pm)
• "hydrogen atomic radius" (53 pm)
• "specific heat of iron" (0.449 J/g*K)
• "iron specific heat capacity" (0.449 J/g*K)
• "modulus of elasticity for aluminum" (70 GPa)
• "aluminum young's modulus" (70 GPa)
• "aluminum young modulus" (70 GPa)
• "latent heat of fusion of aluminum" (397 J/g)
• "aluminum latent heat of fusion" (397 J/g)
• "latent heat of vaporization of aluminum" (10500 J/g)
• "aluminum latent heat of vaporization" (10500 J/g)
• "standard entropy of oxygen gas" (205 J/mol*K)
• "oxygen gas standard entropy" (205 J/mol*K)
• "thermal expansion coefficient of steel" (12e-6 /celsius)
• "steel thermal expansion" (12e-6 /celsius)
• "decay constant of carbon-14" (1.21e-4 /year)
• "carbon-14 decay rate" (1.21e-4 /year)
• "speed of sound in steel" (5950 m/s)
• "sound speed in steel" (5950 m/s)
• "heat of vaporization of mercury" (272 J/g)
• "mercury latent heat of vaporization" (272 J/g)
• "ionization energy of oxygen" (13.6181 eV)
• "oxygen ionization potential" (13.6181 eV)
• "compressibility of helium at 0 C" (0.0034 /MPa)
• "helium compressibility" (0.0034 /MPa)
• "boiling point of helium" (-268.93 celsius)
• "helium boiling temperature" (-268.93 celsius)
• "air molar mass" (28.97 g/mol)
• "vapor pressure of water at 25 C" (3.169 kPa)
• "water vapor pressure at 25 degrees Celsius" (3.169 kPa)
• "density of silicon" (2330 kg/m^3)
• "silicon density" (2330 kg/m^3)
• "band gap of silicon" (1.12 eV)
• "silicon band gap" (1.12 eV)
• "melting point of silicon" (1414 celsius)
• "silicon melting temperature" (1414 celsius)
• "thermal conductivity of silicon" (148 W/m*K)
• "silicon thermal conductivity" (148 W/m*K)
• "specific heat of silicon" (0.703 J/g*K)
• "silicon specific heat capacity" (0.703 J/g*K)
• "decay constant of radium-226" (1.37e-11 /s)
• "radium-226 decay rate" (1.37e-11 /s)
• "maximum tensile strength of carbon nanotubes" (63 GPa)
• "carbon nanotubes tensile strength" (63 GPa)
• "vacuum light speed" (299792458 m/s)
• "luminous intensity of a candela" (1 cd)
• "candela luminous intensity" (1 cd)
• "lifetime of a muon" (2.2e-6 s)
• "muon lifetime" (2.2e-6 s)
• "thermal expansion coefficient of glass" (9e-6 /celsius)
• "glass thermal expansion" (9e-6 /celsius)
• "surface gravity of Mars" (3.71 m/s^2)
• "Mars gravitational pull" (3.71 m/s^2)
• "heat of combustion of gasoline" (47 MJ/kg)
• "gasoline heat of combustion" (47 MJ/kg)
• "acidity (pKa) of water" (15.7)
• "water acidity" (15.7)
• "density of concrete" (2400 kg/m^3)
• "concrete density" (2400 kg/m^3)
• "thermal conductivity of concrete" (1.7 W/m*K)
• "concrete thermal conductivity" (1.7 W/m*K)
• "viscosity of motor oil (SAE 10W-30) at 100 C" (10 cP)
• "motor oil viscosity at 100 C" (10 cP)
• "bulk modulus of elasticity for steel" (160 GPa)
• "steel bulk modulus" (160 GPa)
• "atomic mass of lithium" (6.941 u)
• "lithium atomic mass" (6.941 u)
• "heat capacity of lithium" (3.58 J/g*K)
• "lithium heat capacity" (3.58 J/g*K)
• "expansion coefficient of lithium" (46e-6 /celsius)
• "lithium expansion coefficient" (46e-6 /celsius)
• "resistivity of tungsten at 20 C" (5.6e-8 ohm*m)
• "tungsten resistivity at 20 C" (5.6e-8 ohm*m)
• "surface tension of mercury at 20 C" (485.5 mN/m)
• "mercury surface tension at 20 C" (485.5 mN/m)
• "refractive index of sapphire" (1.77)
• "sapphire refractive index" (1.77)
• "electrical conductivity of copper" (59.6*10^6 S/m)
• "copper electrical conductivity" (59.6*10^6 S/m)
• "shear modulus of copper" (48 GPa)
• "copper shear modulus" (48 GPa)
• "latent heat of vaporization of lead" (871 J/g)
• "lead latent heat of vaporization" (871 J/g)
• "atomic mass of gold" (196.96657 u)
• "gold atomic mass" (196.96657 u)
• "melting point of platinum" (1768.3 celsius)
• "platinum melting temperature" (1768.3 celsius)
• "elastic modulus of platinum" (168 GPa)
• "platinum young's modulus" (168 GPa)
• "platinum young modulus" (168 GPa)
• "boiling point of ethanol" (78.37 celsius)
• "ethanol boiling temperature" (78.37 celsius)
• "heat of combustion of ethanol" (29.7 MJ/kg)
• "ethanol heat of combustion" (29.7 MJ/kg)
• "density of ethanol" (789 kg/m^3)
• "ethanol density" (789 kg/m^3)
• "specific heat of ethanol" (2.44 J/g*K)
• "ethanol specific heat capacity" (2.44 J/g*K)
• "ionization energy of helium" (24.5874 eV)
• "helium ionization potential" (24.5874 eV)
• "luminous efficacy of sunlight" (93 lm/W)
• "sunlight luminous efficacy" (93 lm/W)
• "neutron cross section for uranium-235" (584.6 barns)
• "uranium-235 neutron cross section" (584.6 barns)
• "compression strength of granite" (200 MPa)
• "granite compression strength" (200 MPa)
• "bulk modulus of elasticity for granite" (50 GPa)
• "granite bulk modulus" (50 GPa)
• "modulus of rigidity of granite" (30 GPa)
• "granite modulus of rigidity" (30 GPa)
• "heat capacity of granite" (0.79 J/g*K)
• "granite heat capacity" (0.79 J/g*K)
• "thermal conductivity of granite" (2.4 W/m*K)
• "granite thermal conductivity" (2.4 W/m*K)
• "specific gravity of granite" (2.75)
• "granite specific gravity" (2.75)
• "speed of sound in quartz" (5740 m/s)
• "quartz speed of sound" (5740 m/s)
• "density of quartz" (2650 kg/m^3)
• "quartz density" (2650 kg/m^3)
• "specific heat of quartz" (0.73 J/g*K)
• "quartz specific heat capacity" (0.73 J/g*K)
• "refractive index of quartz" (1.544)
• "quartz refractive index" (1.544)
• "young's modulus of quartz" (78 GPa)
• "young modulus of quartz" (78 GPa)
• "quartz young's modulus" (78 GPa)
• "quartz young modulus" (78 GPa)
• "thermal expansion coefficient of quartz" (0.5e-6 /celsius)
• "quartz thermal expansion" (0.5e-6 /celsius)
• "piezoelectric constant of quartz" (2.3 C/N)
• "quartz piezoelectric constant" (2.3 C/N)
• "modulus of elasticity for titanium" (116 GPa)
• "titanium young's modulus" (116 GPa)
• "titanium young modulus" (116 GPa)
• "thermal expansion coefficient of titanium" (8.6e-6 /celsius)
• "titanium thermal expansion" (8.6e-6 /celsius)
• "thermal conductivity of titanium" (21.9 W/m*K)
• "titanium thermal conductivity" (21.9 W/m*K)
• "electrical resistivity of titanium" (0.42e-6 ohm*m)
• "titanium resistivity" (0.42e-6 ohm*m)
• "melting point of titanium" (1668 celsius)
• "titanium melting temperature" (1668 celsius)
• "density of titanium" (4500 kg/m^3)
• "titanium density" (4500 kg/m^3)
• "boiling point of hydrogen" (-252.87 celsius)
• "hydrogen boiling temperature" (-252.87 celsius)
• "density of hydrogen at STP" (0.08988 kg/m^3)
• "hydrogen density at STP" (0.08988 kg/m^3)
• "thermal conductivity of hydrogen" (0.1805 W/m*K)
• "hydrogen thermal conductivity" (0.1805 W/m*K)
• "ionization energy of nitrogen" (14.5341 eV)
• "nitrogen ionization potential" (14.5341 eV)
• "density of nitrogen at STP" (1.2506 kg/m^3)
• "nitrogen density at STP" (1.2506 kg/m^3)
• "specific heat of nitrogen" (1.04 J/g*K)
• "nitrogen specific heat capacity" (1.04 J/g*K)
• "thermal conductivity of nitrogen" (0.02583 W/m*K)
• "nitrogen thermal conductivity" (0.02583 W/m*K)
• "aluminum thermal expansion" (23.1e-6 /celsius)
• "thermal conductivity of aluminum" (237 W/m*K)
• "aluminum thermal conductivity" (237 W/m*K)
• "electrical resistivity of aluminum" (2.82e-8 ohm*m)
• "aluminum resistivity" (2.82e-8 ohm*m)
• "melting point of aluminum" (660.3 celsius)
• "aluminum melting temperature" (660.3 celsius)
• "density of aluminum" (2700 kg/m^3)
• "aluminum density" (2700 kg/m^3)
• "boiling point of oxygen" (-183 celsius)
• "oxygen boiling temperature" (-183 celsius)
• "density of oxygen at STP" (1.429 kg/m^3)
• "oxygen density at STP" (1.429 kg/m^3)
• "thermal conductivity of oxygen" (0.02658 W/m*K)
• "oxygen thermal conductivity" (0.02658 W/m*K)
• "ionization energy of magnesium" (7.6462 eV)
• "magnesium ionization potential" (7.6462 eV)
• "density of magnesium at STP" (1738 kg/m^3)
• "magnesium density at STP" (1738 kg/m^3)
• "specific heat of magnesium" (1.02 J/g*K)
• "magnesium specific heat capacity" (1.02 J/g*K)
• "thermal conductivity of magnesium" (156 W/m*K)
• "magnesium thermal conductivity" (156 W/m*K)
• "yield strength of stainless steel" (520 MPa)
• "stainless steel yield strength" (520 MPa)
• "modulus of elasticity for stainless steel" (200 GPa)
• "stainless steel young's modulus" (200 GPa)
• "stainless steel young modulus" (200 GPa)
• "thermal expansion coefficient of stainless steel" (17.3e-6 /celsius)
• "stainless steel thermal expansion" (17.3e-6 /celsius)
• "thermal conductivity of stainless steel" (16 W/m*K)
• "stainless steel thermal conductivity" (16 W/m*K)
• "electrical resistivity of stainless steel" (0.72e-6 ohm*m)
• "stainless steel resistivity" (0.72e-6 ohm*m)
• "density of stainless steel" (8000 kg/m^3)
• "stainless steel density" (8000 kg/m^3)
• "boiling point of carbon dioxide" (-78 celsius)
• "carbon dioxide boiling temperature" (-78 celsius)
• "density of carbon dioxide at STP" (1.977 kg/m^3)
• "carbon dioxide density at STP" (1.977 kg/m^3)
• "thermal conductivity of carbon dioxide" (0.0163 W/m*K)
• "carbon dioxide thermal conductivity" (0.0163 W/m*K)
• "ionization energy of copper" (7.7264 eV)
• "copper ionization potential" (7.7264 eV)
• "density of copper at STP" (8960 kg/m^3)
• "copper density at STP" (8960 kg/m^3)
• "specific heat of copper" (0.385 J/g*K)
• "copper specific heat capacity" (0.385 J/g*K)
• "copper thermal conductivity" (401 W/m*K)
• "boiling point of methane" (-161.5 celsius)
• "methane boiling temperature" (-161.5 celsius)
• "density of methane at STP" (0.656 kg/m^3)
• "methane density at STP" (0.656 kg/m^3)
• "thermal conductivity of methane" (0.0342 W/m*K)
• "methane thermal conductivity" (0.0342 W/m*K)
• "ionization energy of silicon" (8.1517 eV)
• "silicon ionization potential" (8.1517 eV)
• "density of silicon at STP" (2330 kg/m^3)
• "silicon density at STP" (2330 kg/m^3)
• "modulus of elasticity for concrete" (25 GPa)
• "concrete young's modulus" (25 GPa)
• "concrete young modulus" (25 GPa)
• "thermal expansion coefficient of concrete" (12e-6 /celsius)
• "concrete thermal expansion" (12e-6 /celsius)
• "ionization energy of lead" (7.4167 eV)
• "lead ionization potential" (7.4167 eV)
• "density of lead at STP" (11340 kg/m^3)
• "lead density at STP" (11340 kg/m^3)
• "specific heat of lead" (0.128 J/g*K)
• "lead specific heat capacity" (0.128 J/g*K)
• "thermal conductivity of lead" (35 W/m*K)
• "lead thermal conductivity" (35 W/m*K)
• "electrical resistivity of lead" (208e-9 ohm*m)
• "lead resistivity" (208e-9 ohm*m)

Example conversions:

Length

• Inches to Centimeters: Multiply the length value in inches by 2.54 to convert it to centimeters.
• Feet to Meters: Multiply the length value in feet by 0.3048 to convert it to meters.
• Yards to Meters: Multiply the length value in yards by 0.9144 to convert it to meters.
• Miles to Kilometers: Multiply the distance value in miles by 1.60934 to convert it to kilometers.

Mass

• Ounces to Grams: Multiply the mass value in ounces by 28.3495 to convert it to grams.
• Pounds to Kilograms: Multiply the mass value in pounds by 0.453592 to convert it to kilograms.
• Stones to Kilograms: Multiply the mass value in stones by 6.35029 to convert it to kilograms.

Temperature

• Fahrenheit to Celsius: Subtract 32 from the temperature in Fahrenheit, then multiply by 5 and divide by 9 to get the temperature in Celsius.
• Celsius to Fahrenheit: Multiply the temperature in Celsius by 9, divide by 5, and then add 32 to convert it to Fahrenheit.

Speed

• Miles per Hour to Kilometers per Hour: Multiply the speed value in miles per hour by 1.60934 to convert it to kilometers per hour.
• Knots to Kilometers per Hour: Multiply the speed value in knots by 1.852 to convert it to kilometers per hour.

Volume

• Gallons to Liters: Multiply the volume value in gallons by 3.78541 to convert it to liters.
• Cups to Milliliters: Multiply the volume value in cups by 236.588 to convert it to milliliters.
• Pints to Liters: Multiply the volume value in pints by 0.473176 to convert it to liters.

These conversions can be extremely helpful for a variety of everyday tasks, such as cooking, measuring distances, and gauging weights.

Area

• Square Inches to Square Centimeters: Multiply the area value in square inches by 6.4516 to convert it to square centimeters.
• Square Feet to Square Meters: Multiply the area value in square feet by 0.092903 to convert it to square meters.
• Acres to Hectares: Multiply the area value in acres by 0.404686 to convert it to hectares.

Pressure

• Pounds per Square Inch (PSI) to Pascals: Multiply the pressure value in PSI by 6894.76 to convert it to pascals.
• Bars to Atmospheres: Divide the pressure value in bars by 1.01325 to convert it to standard atmospheres.
• Millimeters of Mercury (mmHg) to Pascals: Multiply the pressure value in mmHg by 133.322 to convert it to pascals.

Energy

• Joules to Calories: Divide the energy value in joules by 4.184 to convert it to calories.
• Kilowatt-hours to Joules: Multiply the energy value in kilowatt-hours by 3.6 million to convert it to joules.
• British Thermal Units (BTU) to Joules: Multiply the energy value in BTU by 1055.06 to convert it to joules.

Density

• Pounds per Cubic Foot to Kilograms per Cubic Meter: Multiply the density value in pounds per cubic foot by 16.0185 to convert it to kilograms per cubic meter.
• Grams per Cubic Centimeter to Kilograms per Cubic Meter: Multiply the density value in grams per cubic centimeter by 1000 to convert it to kilograms per cubic meter.

Additional Examples

Length

• Centimeters to Inches: Divide the length value in centimeters by 2.54 to convert it to inches.
• Kilometers to Miles: Divide the distance value in kilometers by 1.60934 to convert it to miles.

Mass

• Grams to Ounces: Divide the mass value in grams by 28.3495 to convert it to ounces.
• Kilograms to Pounds: Divide the mass value in kilograms by 0.453592 to convert it to pounds.

Temperature

• Kelvin to Celsius: Subtract 273.15 from the temperature in Kelvin to convert it to Celsius.
• Celsius to Kelvin: Add 273.15 to the temperature in Celsius to convert it to Kelvin.

Speed

• Kilometers per Hour to Miles per Hour: Divide the speed value in kilometers per hour by 1.60934 to convert it to miles per hour.
• Meters per Second to Kilometers per Hour: Multiply the speed value in meters per second by 3.6 to convert it to kilometers per hour.

Volume

• Liters to Gallons: Divide the volume value in liters by 3.78541 to convert it to US gallons.
• Milliliters to Fluid Ounces (US): Divide the volume value in milliliters by 29.5735 to convert it to US fluid ounces.

These additional conversions enrich the utility of the unit converter across various fields, making it a comprehensive tool for academic, professional, and personal uses.

Time

• Seconds to Minutes: Divide the time value in seconds by 60 to convert it to minutes.
• Minutes to Hours: Divide the time value in minutes by 60 to convert it to hours.
• Hours to Days: Divide the time value in hours by 24 to convert it to days.
• Days to Weeks: Divide the time value in days by 7 to convert it to weeks.
• Weeks to Years: Divide the time value in weeks by 52.1775 to convert it to years.

Power

• Watts to Kilowatts: Divide the power value in watts by 1000 to convert it to kilowatts.
• Kilowatts to Horsepower: Multiply the power value in kilowatts by 1.34102 to convert it to horsepower.
• Horsepower to Watts: Multiply the power value in horsepower by 745.7 to convert it to watts.
• Calories per Hour to Joules per Second (Watts): Divide the power value in calories per hour by 0.859845 to convert it to watts.

Digital Data

• Bytes to Kilobytes: Divide the data value in bytes by 1024 to convert it to kilobytes.
• Kilobytes to Megabytes: Divide the data value in kilobytes by 1024 to convert it to megabytes.
• Megabytes to Gigabytes: Divide the data value in megabytes by 1024 to convert it to gigabytes.
• Gigabytes to Terabytes: Divide the data value in gigabytes by 1024 to convert it to terabytes.

Additional Details for Existing Categories

Area

• Square Meters to Square Kilometers: Divide the area value in square meters by 1,000,000 to convert it to square kilometers.
• Hectares to Square Meters: Multiply the area value in hectares by 10,000 to convert it to square meters.

Pressure

• Pascals to Kilopascals: Divide the pressure value in pascals by 1000 to convert it to kilopascals.
• Atmospheres to Bars: Multiply the pressure value in atmospheres by 1.01325 to convert it to bars.

Energy

• Calories to Kilocalories: Divide the energy value in calories by 1000 to convert it to kilocalories.
• MegaJoules to KiloJoules: Multiply the energy value in megajoules by 1000 to convert it to kilojoules.

Density

• Kilograms per Cubic Meter to Pounds per Cubic Foot: Divide the density value in kilograms per cubic meter by 16.0185 to convert it to pounds per cubic foot.
• Kilograms per Liter to Grams per Milliliter: Since 1 kilogram per liter is equivalent to 1 gram per milliliter, no conversion is necessary.

By including these diverse categories and conversion specifics, the converter now spans a wide array of disciplines and applications, from everyday tasks to specialized engineering and scientific calculations. This comprehensive guide should serve as a handy reference for converting most common units encountered in daily life and professional settings.

To further expand our unit converter, let's delve into more specialized categories such as light, fuel economy, cooking measurements, and electromagnetic units. These additions will make the converter even more versatile and useful in various specialized and everyday contexts.

Light

• Lumens to Lux: Divide the light value in lumens by the area in square meters over which the light is dispersed to convert it to lux.
• Candela to Lumens: Multiply the intensity value in candela by the solid angle in steradians to convert it to lumens.
• Foot-candles to Lux: Multiply the light value in foot-candles by 10.764 to convert it to lux.

Fuel Economy

• Miles per Gallon (MPG) to Liters per 100 Kilometers (L/100km): Divide 235.214 by the fuel economy value in MPG to convert it to L/100km.
• Liters per 100 Kilometers to Miles per Gallon: Divide 235.214 by the fuel economy value in L/100km to convert it back to MPG.
• Kilometers per Liter to Miles per Gallon: Multiply the fuel economy value in kilometers per liter by 2.352 to convert it to miles per gallon.

Cooking Measurements

• Teaspoons to Milliliters: Multiply the volume value in teaspoons by 4.92892 to convert it to milliliters.
• Tablespoons to Milliliters: Multiply the volume value in tablespoons by 14.7868 to convert it to milliliters.
• Cups to Liters: Multiply the volume value in cups by 0.24 to convert it to liters.

Electromagnetic Units

• Amperes to Coulombs per Second: Since 1 ampere is defined as 1 coulomb per second, no conversion is necessary.
• Volts to Joules per Coulomb: Since 1 volt is defined as 1 joule per coulomb, no conversion is necessary.
• Tesla to Gauss: Multiply the magnetic field strength in tesla by 10,000 to convert it to gauss.

Additional Examples for Existing Categories

Power

• Gigawatts to Megawatts: Multiply the power value in gigawatts by 1,000 to convert it to megawatts.
• Joules per Second to Kilowatts: Divide the power value in joules per second (watts) by 1,000 to convert it to kilowatts.

Digital Data

• Terabytes to Petabytes: Divide the data value in terabytes by 1,024 to convert it to petabytes.
• Bits to Bytes: Divide the data value in bits by 8 to convert it to bytes.

Pressure

• Kilopascals to Megapascals: Divide the pressure value in kilopascals by 1,000 to convert it to megapascals.
• Pascals to Bar: Divide the pressure value in pascals by 100,000 to convert it to bar.

This expanded converter now addresses a broader spectrum of measurements, helping you navigate through conversions related to illumination, automotive fuel efficiency, culinary arts, and electromagnetic specifications. This tool is ideal for both professionals in specialized fields and individuals dealing with everyday measurement conversions.

Expanding further, let's delve into conversions for sound, viscosity, radiation, and angular measurements. This will equip the converter to handle even more specialized fields like acoustics, fluid dynamics, nuclear science, and engineering.

Sound

• Decibels to Intensity (Watts per square meter): The relationship between decibels and intensity is logarithmic. To convert a sound level from decibels (dB) to intensity ( I ) in watts per square meter, use ( I = 10^{(\text{dB}/10 - 12)} ).
• Hertz to Kilohertz: Divide the frequency value in hertz by 1,000 to convert it to kilohertz.

Viscosity

• Poise to Pascal-seconds: Multiply the viscosity value in poise by 0.1 to convert it to pascal-seconds.
• Centipoise to Millipascal-seconds: Multiply the viscosity value in centipoise by 0.001 to convert it to millipascal-seconds.

Radiation

• Curie to Becquerel: Multiply the radioactivity value in curie by ( 3.7 \times 10^{10} ) to convert it to becquerel.
• Rad to Gray: Multiply the absorbed dose value in rad by 0.01 to convert it to gray.
• Röntgen to Coulombs/kg: Multiply the exposure value in röntgen by 2.58 × 10^{-4} to convert it to coulombs per kilogram.

Angular Measurements

• Degrees to Radians: Multiply the angle in degrees by ( \pi/180 ) to convert it to radians.
• Radians to Degrees: Multiply the angle in radians by ( 180/\pi ) to convert it to degrees.
• Gradians to Degrees: Multiply the angle in gradians by 0.9 to convert it to degrees.

Additional Detailed Examples for Existing Categories

Light

• Lux to Foot-candles: Divide the light intensity value in lux by 10.764 to convert it to foot-candles.
• Lux to Watts per Square Meter: For visible light, an approximate conversion can be calculated based on the light's wavelength. Typically, 1 lux is approximately equal to 0.0079 watts per square meter at a wavelength of 555 nm (peak sensitivity).

Fuel Economy

• Miles per Gallon to Kilometers per Liter: Multiply the fuel economy value in miles per gallon by 0.425144 to convert it to kilometers per liter.
• Kilometers per Liter to Liters per 100 Kilometers: Divide 100 by the fuel economy value in kilometers per liter to convert it.

Cooking Measurements

• Fluid Ounces (US) to Liters: Multiply the volume value in fluid ounces by 0.0295735 to convert it to liters.
• Pounds to Cups (for specific ingredients): This conversion can vary significantly based on the ingredient due to density differences. For example, 1 pound of flour typically converts to about 3.6 cups.

Electromagnetic Units

• Gauss to Microtesla: Multiply the magnetic field strength in gauss by 100 to convert it to microtesla.
• Kilovolts per Meter to Volts per Meter: Multiply the electric field strength in kilovolts per meter by 1,000 to convert it to volts per meter.

This expanded set of conversions now covers a broad range of fields, making it an invaluable tool for professionals across various scientific, engineering, and technical disciplines, as well as for students and educators in related fields.

What are Physical Units? Kinds of Physical Units

Physical units are fundamental in science, especially in fields such as physics, chemistry, and engineering, as they provide a standard measurement to quantify and describe physical quantities. Understanding physical units is essential for interpreting data correctly, designing experiments, and communicating scientific results universally.

Definition of Physical Units

Physical units are standardized quantities used to measure and express physical quantities such as length, mass, time, and temperature. They allow scientists and engineers to convey information with clarity and precision, ensuring that measurements are understood and reproducible by anyone, anywhere in the world.

Importance of Physical Units

• Standardization: Units provide a consistent way of measuring physical properties, which is crucial for global collaboration and comparison of scientific data.
• Communication: Clear units prevent misunderstandings in scientific and commercial exchanges that could arise from differing measurement systems.
• Safety: In industries like engineering and manufacturing, precise measurements and the correct application of units can be critical for safety.
• Research and Development: Accurate measurement with standardized units is crucial for research, allowing for validation of theories and innovations.

Kinds of Physical Units

Physical units can be broadly classified into several types:

1. Basic or Fundamental Units

   • These units are the core units from which all other units are derived and are not dependent on any other units. Examples include:
     • Meter (m) for length
     • Kilogram (kg) for mass
     • Second (s) for time
     • Ampere (A) for electric current
     • Kelvin (K) for thermodynamic temperature
     • Mole (mol) for amount of substance
     • Candela (cd) for luminous intensity
   • The International System of Units (SI) defines these seven units as the base units from which all other units are derived.

2. Derived Units

   • Derived units are created from the base units through mathematical relationships. For example:
     • Speed has the unit meters per second (m/s), derived from the fundamental units of meters and seconds.
     • Force is measured in newtons (N), which is derived as kg·m/s².
   • These units cover a broad range of scientific measurements and are crucial for describing phenomena like force, energy, and pressure.

3. Supplementary Units

   • Previously, units like radians (rad) for angular measure and steradians (sr) for solid angles were considered supplementary, but they are now grouped under derived units in the SI system.

4. Non-SI Units Still in Use

   • Despite the widespread adoption of the SI system, some non-SI units are still commonly used in specific fields:
     • Minutes, hours, and days for time
     • Degrees Celsius (°C) for temperature in weather forecasts
     • Miles, yards, feet, and inches in countries like the United States for distance

5. Dimensionless Units

   • Some quantities are expressed as pure numbers without any physical dimensions. These include:
     • Refractive index
     • Relative density
     • Poisson’s ratio

6. Natural Units

   • Used primarily in theoretical physics, natural units are chosen so that certain fundamental physical constants take on the value of 1, simplifying equations and concepts. Examples include:
     • Planck units
     • Atomic units
     • Electronvolt (eV) for energy in particle physics

The use of physical units is a cornerstone of scientific inquiry and technological development. The standardization provided by systems like the SI units enables seamless communication and operational efficiency across diverse disciplines and industries. As science progresses, the system of units also evolves, adapting to new discoveries and technologies to better serve the scientific community and society at large. Understanding and correctly using physical units is foundational for anyone involved in scientific or engineering endeavors.

Challenges and Evolution in the Use of Physical Units

As our understanding of the physical world deepens and new technologies emerge, the system of physical units must adapt to meet new scientific demands and precision requirements. This evolution poses both challenges and opportunities for the scientific community.

1. Challenges in Measurement Precision

   • As scientific and engineering projects become more complex, the precision required in measurements increases. This necessitates continual improvement and calibration of measurement instruments and methods.
   • Achieving high precision in measurements often requires advanced technology and methodologies, which can be cost-prohibitive or technologically demanding.

2. Adapting to New Scientific Discoveries

   • New scientific discoveries can lead to the introduction of new units or the redefinition of existing ones. For example, the redefinition of the kilogram in 2019 was based on fundamental physical constants rather than a physical artifact.
   • These changes require widespread dissemination and education to ensure that they are adopted uniformly across different scientific and engineering disciplines.

3. Global Standardization Issues

   • While the SI system is internationally recognized, the transition to a fully standardized global system encounters resistance due to historical, cultural, and practical reasons.
   • Non-SI units still prevalent in some regions and fields (like the use of feet and inches in the aviation industry) pose challenges for international collaboration and data sharing.

Opportunities in Standardization of Units

The ongoing evolution in the standardization of physical units also presents several opportunities:

1. Increased Global Collaboration

   • Harmonizing measurement systems across the world can enhance international collaboration in science and technology, facilitating easier exchange of data and research findings.

2. Enhanced Precision and Innovation

   • Innovations in measurement technologies and the introduction of units based on universal constants (like the Planck constant for mass) lead to greater precision. This, in turn, drives further scientific and technological advances.

3. Education and Outreach

   • Changes in the system of physical units provide an excellent opportunity for educational initiatives that can enhance public understanding of science and the importance of measurements.

4. Environmental and Economic Benefits

   • Improved measurement techniques can lead to more efficient resource use and better environmental monitoring, aligning scientific progress with sustainability goals.

The Future of Physical Units

Looking to the future, the landscape of physical units may continue to change as more precise and universal methods of measurement are developed. The trend towards a more interconnected and technologically advanced global society will likely push for further standardization and innovation in how we measure and understand the physical world.

The evolution of physical units is not just a matter of scientific interest but also a reflection of the broader human quest for understanding, precision, and efficiency in all areas of life. As we look forward, the integration of new scientific insights and technological advancements will undoubtedly shape the future of physical units, continuing to influence science, industry, and daily life around the globe.

Technological Advancements and Their Impact on Physical Units

The advancement of technology significantly influences how physical units are defined and utilized, driving precision to unprecedented levels and enabling new forms of measurements that were once thought impossible.

1. Quantum Standards for Measurement

   • Quantum technology provides methods to measure physical quantities with extreme accuracy. For example, atomic clocks use the vibrations of atoms to keep time with phenomenal precision, which is crucial for GPS technology and global communications.
   • Quantum sensors are emerging tools capable of detecting and measuring physical quantities at the atomic scale, which can revolutionize fields such as medicine, navigation, and environmental monitoring.

2. Digitalization and Data Science

   • The rise of digital technology impacts how measurements are performed and processed. High-speed computing allows for the rapid analysis of large datasets, improving the accuracy of measurements by identifying patterns and anomalies that were not previously detectable.
   • Machine learning and AI are increasingly used to refine measurement techniques and predict outcomes based on historical data, enhancing the reliability of physical units in experimental and real-world applications.

3. Nanotechnology

   • At the nanoscale, traditional concepts of measurement face new challenges due to quantum effects and the behavior of materials at atomic sizes. Nanotechnology pushes the development of new units and measurement techniques that can operate effectively at this scale.

International Efforts in the Standardization of Units

Global cooperation plays a pivotal role in the evolution and standardization of physical units. International bodies such as the International Bureau of Weights and Measures (BIPM) and the International Organization of Legal Metrology (OIML) work tirelessly to maintain and refine the definitions of physical units.

• Periodic Review and Update of Standards
  • The International System of Units (SI) is periodically updated to reflect advances in scientific understanding and measurement technology. These updates ensure that global measurement standards remain relevant and reliable.
• Education and Training
  • International workshops, symposia, and training programs are conducted regularly to educate scientists and industry professionals worldwide about the latest developments in measurement standards and technologies.

The Role of Education in Understanding Physical Units

Education in the science of measurement, also known as metrology, is crucial for the effective use of physical units across various scientific and engineering disciplines.

• Curriculum Integration
  • Integrating advanced concepts of metrology and the importance of standard units into educational curricula at all levels—from primary through tertiary education—can help cultivate a strong foundation in the scientific method.
• Public Outreach
  • Public outreach programs that explain the role of physical units in everyday life can help demystify science and highlight the practical importance of accurate measurement.

The world of physical units is a dynamic field influenced by ongoing scientific discoveries, technological innovations, and international collaboration. The future promises even more precision and standardization as we continue to explore the universe at both the grandest and most minute scales. Understanding and using physical units effectively will remain a cornerstone of scientific progress and a key to unlocking new technologies that could transform our understanding of the world. This continuous evolution of measurement standards not only reflects our growing scientific capability but also our enduring commitment to precision, efficiency, and universal cooperation.

Ethical Considerations in the Standardization of Physical Units

As the standardization of physical units progresses, it also brings to light various ethical considerations that must be addressed to ensure fairness and equity in scientific practices and international collaboration.

1. Access to Technology

   • The disparity in access to advanced measurement technologies between developed and developing countries can lead to inequalities in scientific research and its applications. Ensuring that all countries have fair access to the latest measurement technologies and standards is crucial for global scientific equity.
   • International bodies and wealthier nations can play a pivotal role in providing resources, training, and technology transfers to less developed regions to help level the playing field.

2. Intellectual Property

   • With advancements in measurement technologies often comes proprietary technology and software. This can create barriers to entry for researchers and industries unable to afford these tools. Balancing intellectual property rights with the need for widespread access to scientific tools is a significant ethical and legal challenge.
   • Open-source alternatives and collaborative licensing models could be promoted to enhance access to essential technologies across the globe.

3. Data Privacy and Security

   • Modern measurement technologies, especially those integrated with digital and AI tools, can collect vast amounts of data. Ensuring the privacy and security of this data is paramount to protect individuals and organizations from potential misuse.
   • Regulations and standards must be developed to govern the ethical use of data in scientific and industrial measurements, with a clear emphasis on respecting privacy and ensuring data security.

Future Trends in Physical Units and Measurement

The future of physical units and their measurement is likely to be shaped by several emerging trends and innovations:

1. Interdisciplinary Approaches

   • Future developments in physical units may see more interdisciplinary approaches, integrating insights from physics, chemistry, biology, and computer science to develop new types of measurements that can more accurately describe complex systems.
   • For example, biologically inspired measurement systems could emerge, utilizing principles from nature to create more efficient and adaptable measurement tools.

2. Miniaturization and Integration

   • The trend towards miniaturization continues, with sensors and measurement devices becoming smaller, more efficient, and easier to integrate into other technologies. This could lead to the development of wearable sensors and embedded devices that provide real-time data collection and analysis for health monitoring, environmental sensing, and industrial automation.
   • Such advancements could transform how and where measurements are conducted, making them more ubiquitous and integrated into our everyday lives.

3. Global Standards for Emerging Technologies

   • As new technologies such as quantum computing and nanotechnology mature, establishing global standards for their measurement implications will be crucial. This includes defining how units like qubits (quantum bits) and nanoscale properties are standardized and measured.
   • International collaboration will be essential to develop these standards, ensuring they are robust, widely accepted, and capable of facilitating innovation while maintaining compatibility with existing measurement systems.

The exploration of physical units and their measurement is a journey that mirrors the progress of human knowledge and technology. As we venture further into this scientific domain, the importance of maintaining rigorous standards, ethical considerations, and global cooperation cannot be overstated. These elements are fundamental to ensuring that advancements in measurement science contribute positively to society, enhancing our ability to understand, explore, and responsibly utilize the physical world. As technology evolves and new challenges arise, the global scientific community must remain vigilant and proactive in fostering an environment where innovation is balanced with ethical responsibility and accessibility.