The siphon Most people are familiar with the use of a siphon for removing water from fish aquaria or other receptacles which cannot otherwise be emptied conveniently. The siphon is a bent tube made of glass, rubber, or plastic tubing with its short arm dipping into the tank of liquid and its longer arm outside (Fig. 11.9). To start […]
To compare the densities of two liquids by means of Hare’s apparatus In chapter 9 we saw how the relative density of a liquid can be found by the use of a density bottle. The following method for measuring the relative density of a liquid is based on the pressure exerted by a liquid column. The apparatus consists […]
The transmission of pressure in fluids. Hydraulic brake When the fluid is completely enclosed in a vessel and a pressure is applied to it at an. part of its surface, as for example, by means of a cylinder and piston connected to the vessel, then the pressure is transmitted equally throughout the whole of the enclos fluid. This […]
The preserving jar Atmospheric pressure is used in the kitchen in connection with the preservation of fruit which is unsuitable for deepfreezing. The preserving jar, is a glass jar covered with a metal cap seated on a flat rubber ring (Fig. 11.5). Clean fruit and water are placed in the jar, leaving a small air space at the […]
Early fire pumps Towards the end of the eighteenth century manual fire pumps came into use which consisted of a pair of force pumps connected to a long handle and worked by a team of four men. Both pumps fed alternately into a chamber with a compressed air space similar to that described above. At the moment of […]
The force pump For raising water to a height of more than 10 m, the force pump is used (Fig. 11.3). It consists of a pump with a solid plunger and foot valve B, connected by a pipe to a chamber C through a valve A. The upstroke (Fig. 11.3 (a)) On the upstroke valve A closes […]
The common pump (lift pump) Pumps were used successfully to raise water from wells long before their action was properly understood, and are still to be seen in country villages, carefully preserved as relics of the past. They consist of a cylindrical metal barrel with a side tube near the top to act as a spout (Fig. 11.2).At […]
Application of atmospheric and liquid pressure The rubber sucker A very useful application of atmospheric pressure is found in a circular shallow rubber cup known as a sucker. These are used for attaching notices to shop windows and for similar purposes. When the rubber is moistened to obtain a good air seal and pressed on a smooth flat surface […]