Hydrostatics Archimedes’ principle

The result that Archimedes discovered was the first law of hydrostatics, better known as Archimedes Principle. Aixhimedes studied fluids at rest, hydrostatics, and it was nearly 2,000 years before Daniel Bernoulli took the next step when he combined Archimedes idea of pressure with Newton s laws of motion to develop the subject of fluid dynamics. 

Archimedes of Syracuse (287-212 bc) Greek mathematician, who spent most of his life at his birthplace working on levers and other aspects of mechanics, in hydrostatics he devised a pump (the Archlmedlan screw) and formulated Archimedes principle. His method of successive approximation allowed him to determine the value of re to a good approximation and some of his work came close to anticipating integral calculus. He was killed by a soldier in the Roman siege of Syracuse. 

Archimedes principle Aprinciplethatstateswhenabodyfloalsitdisplacesaweight of liquid equal to its own weight. The principle was not stated by Archimedes but is connected to his discoveries in hydrostatics. When a body is partially or totally immersed in a liquid, there is an upthrust on the body equal to the weight of the liquid displaced by the body. 

This is a convenient point at which to introduce the concept of water in the ground, water table, pressure and pressure measurement and some simple hydrostatics - buoyancy, Archimedes - and ideas of surface tension. This then leads to the logical partition of total stress (which is what we discover that we have been thinking about in applying considerations of equilibrium to the vertical profile of stress in the ground) between pore pressure and effective stress supported by the soil particles. I do not think it is necessary to dwell on putative proofs of the Principle of Effective Stress. It can be treated as a moderately well non-falsified conjecture which has demonstrated its worth over many decades. In early year teaching it is helpful to convey certainties even if we expect to encourage students to query them later on. 

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