Physical Constants
Pi: 3
Speed of light: 3 x 108 m/s
Planck’s constant: 7 x 10-34 J s
Elementary charge: 2 x 10-19 C
Avogadro’s constant: 6 x 1023
Boltzmann’s constant: 1 x 10-23 J/K (= R/NA)
Stefan-Boltzmann constant: 6 x 10-8 W m-2 K-4
Universal gravitational constant: 7 x 10-11 m3 kg-1 s-2
Universal gas constant = 8 J/mol K
Atoms and Molecules
Atomic radius: 1 angstrom = 10-10 m
Electron binding energy: 3 eV
Mass of an electron: 10-30 kg
Mass of a proton: 2000 x melectron
Mass of a neutron: same as proton
Radius of a proton: 10-15 m
Earth
World Population: 6 x 109
US Population: 3 x 108
Mass of Earth: 6 x 1024 kg
Radius of Earth: 6 x 106 m
Radius of Earth’s orbit: 8 light minutes
Solar constant: 1 x 103 W/m2
Atmospheric sea level pressure: 1 x 105 Pa
Gravitational acceleration: 10 m/s2
Solar System
Radius of sun: 102 Rearth
Radius of moon: 1/4 Rearth
Radius of Mars: 1/2 Rearth
Radius of Venus: 1 Rearth
Radius of Jupiter: 10 Rearth
Water
Density: 1 x 103 kg/m3
Dynamic viscosity: 1 x 10-3 Pa s
Heat capacity: 4 x 103 J/kg K
Latent heat of vaporization: 2 x 106 J/kg
Latent heat of fusion: 3 x 105 J/kg
Air
Density: 1 kg/m3
Dynamic viscosity: 1 x 10-5 Pa s
Heat capacity: 1 x 103 J/kg K
Rocks
Density: 4 x 103 kg/m3
Dynamic viscosity: 1019 to 1024 Pa s
Heat capacity: 1 x 103 J/kg K
Thermal expansivity: 10-4 K-1
Thermal diffusivity: 10-6 m2/s
Silicate heat production: 10-11 W/kg
Biology
Aerobic respiration: 500 kJ/mole of carbon
Mammal power consumption: 1 W/kg
Foods like fats and carbohydrates have an energy content of 5 to 10 kcal/g.
Redfield Ratio C:N:P is 100:10:1
Energy
US per capita power consumption: 10 kW
Global per capita power consumption: 2 kW
Mean incident solar radiation: 300 W
Nuclear fusion: 1 MeV/nucleon/atomic mass [Note: this is per atomic mass basis and also different from the notes]
Nuclear fission: 10-2 MeV/nucleon/atomic number [Note: this is per atomic number basis]
Rules of Thumb
For circular motion, use angular frequency (radians/second) instead of frequency (per second); otherwise factors of 2*pi often get involved.
Use diameter rather than radius as a typical length scale (compare surface area and volume of sphere) since this better represents the size of the object.