Original entry: Ian Burgess, fall 2009
Buoyancy is the upward force that causes particles with lower density to float in a fluid, and particles with greater density to appear lighter when submerged in a fluid. For an object submerged or partially submerged in a liquid, the upward buoyancy force is equal to the weight of the liquid occupying the same volume as the submerged part of the object. For objects with smaller density than the fluid, the portion of the particle submerged can be calculated by finding the equilibrium between the gravitational and buoyancy forces.
R.A. Serway, J.W. Jewitt, Physics for Scientists and Engineers, 8th Ed Brooks Cole Pub Co, 2009.