Some molecular properties of matter

An experiment to demonstrate terminal velocity

An experiment to demonstrate terminal velocity A tall glass jar or a tube fitted with a secure bung at its lower end about 5 em in diameter and 50 em in height is filled with glycerin and supported vertically (Fig. 13.16). Small bearing balls handled with tweezers are then allowed to fall centrally down the tube by dropping …

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Industrial applications of metallurgical studies

Industrial applications of metallurgical studies The behavior of metals and alloys under stress is important in connection with the forging of metal components. In this process the hot or cold metal is squeezed or hammered into shape instead of being cast in a mould (Fig. 13.11 and 13.12). Fig. 13.13 shows the crystal grain flow which takes place …

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Strength of materials. Elasticity

Strength of materials. Elasticity Before various materials are used in the construction of machinery and buildings, tests are carried out to ensure that they are able safely to stand up to the stresses to which they are likely to be subjected. Industrial laboratories have special apparatus for carrying out these tests. Brittle substances such as masonry and cast iron …

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Osmosis

Osmosis Before cooking dried fruits such as prunes and apricots it is customary to lea soaking in cold water for some hours so that they swell up and become rest far as possible, to their original condition. During this time water passes through cell walls of the fruit by a process called osmosis. Osmosis can be demonstrated …

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Molecular explanation of surface tension

Molecular explanation of surface tension On page 140 we explained that the molecules of a liquid are constantly oscillating to and fro alternately exerting repulsive and attractive forces on one another, yet free to move in the body of the liquid, exchanging partners as they go. Application of the kinetic theory, together with knowledge of how the force between …

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Further illustrations of surface tension

Further illustrations of surface tension We have already seen that soap solution, detergents, and alcohol will lower surface tension of water. Camphor has a similar effect. When a piece of champion thrown on to the surface of water it slowly dissolves and causes a reduction  surface tension in its immediate neighbourhood. The stronger pull exerted by surrounding uncontaminated …

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