Pressure Pfluid = ρgh Pfluid is pressure in Pa or N/m² ρ is the density of the fluid in kg/m³ density of water at 20C = 0.998 g/cm³ = 998 kg/m³ density of seawater = 1.025 g/cm³ = 1025 kg/m³ g is the acceleration of gravity 9.8 m/s² h is the height of the fluid above the object in m Ptotal = Patmosphere + Pfluid Patmos = 1.01e5 N/m² or 101 kPa One bar is 100 kPa Buoyancy, Archimedes' principle Buoyancy force is equal to the weight of the displaced fluid. Any object, wholly or partially immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the object For a sunken object the volume of displaced fluid is the volume of the object, and for a floating object on a liquid, the weight of the displaced liquid is the weight of the object apparent immersed weight = weight – weight of displaced fluid density of object / density of fluid = weight / weight of displaced fluid density of object / density of fluid = weight / (weight – apparent immersed weight) Pascal's law or the Principle of transmission of fluid-pressure states that "pressure exerted anywhere in a confined incompressible fluid is transmitted equally in all directions throughout the fluid such that the pressure ratio (initial difference) remains the same. ΔP = ρg(Δh) ΔP is the hydrostatic pressure (given in pascals in the SI system), or the difference in pressure at two points within a fluid column, due to the weight of the fluid; ρ is the fluid density (in kilograms per cubic meter in the SI system); g is acceleration due to gravity (normally using the sea level acceleration due to Earth's gravity in metres per second squared); Δh is the height of fluid above the point of measurement, or the difference in elevation between the two points within the fluid column (in metres in SI). Air pressure versus altitude. P = Po [ 1 – (Lh/To) ]^(gM/RL) P is pressure in Pa Po sea level standard atmospheric pressure 101325 Pa h altitude in meters L temperature lapse rate 0.0065 K/m To sea level standard temperature 288 K g Earth-surface gravitational acceleration 9.81 m/s² M molar mass of dry air 0.0290 kg/mol R universal gas constant 8.31 J/(mol•K) Home Area, Volume Atomic Mass Black Body Radiation Boolean Algebra Calculus Capacitor Center of Mass Carnot Cycle Charge Chemistry   Elements   Reactions Circuits Complex numbers Constants Curves, lines deciBell Density Electronics Elements Flow in fluids Fourier's Law Gases Gravitation Greek Alphabet Horizon Distance Interest Magnetics Math   Trig Math, complex Maxwell's Eq's Motion Newton's Laws Octal/Hex Codes Orbital Mechanics Particles Parts, Analog IC   Digital IC   Discrete Pendulum Planets Pressure Prime Numbers Questions Radiation Refraction Relativistic Motion Resistance, Resistivity Rotation Series SI (metric) prefixes Skin Effect Specific Heat Springs Stellar magnitude Thermal Thermal Conductivity Thermal Expansion Thermodynamics Trigonometry Units, Conversions Vectors Volume, Area Water Wave Motion Wire, Cu   Al   metric Young's Modulus