ABSTRACT
This chapter considers some very important thermo-fluid parameters, including density, pressure and its measurement, temperature and its measurement and linear expansion. It discusses the nature of heat, in particular, specific heat and latent heat and looks at the expansion and contraction of gases and the use of the gas laws, including the two forms of the characteristic gas equation. Devices used to measure pressure will depend on the magnitude of the pressure, accuracy of the desired readings and whether pressure is static or dynamic. In thermodynamics, two specified conditions are used, those of constant volume and constant pressure. A pressure gauge is designed to read zero when subject to atmospheric pressure; therefore, if a gauge is connected to a pressure vessel it will only read gauge pressure. Thus, the atmospheric pressure can be calculated from the height of column of mercury it can support. Variations in pressure are felt on the capsule, which causes it to act on the spring.
