ABSTRACT

This chapter describes fluid pressure and also defines Archimedes Principle, which is used to determine the buoyancy of boats, yachts, ships, etc. The chapter also describes gauges used in fluid mechanics, such as barometers, manometers, the Bourdon pressure gauge, and vacuum gauges. Vacuum gauges are instruments for giving a visual indication, by means of a pointer, of the amount by which the pressure of a fluid applied to the gauge is less than the pressure of the surrounding atmosphere. A barometer is an instrument for measuring atmospheric pressure. A manometer is a device for measuring or comparing fluid pressures, and is the simplest method of indicating such pressures. Archimedes principle states that, if a solid body floats, or is submerged, in a liquid, the liquid exerts an upthrust on the body equal to the gravitational force on the liquid displaced by the body.