Contraction of length

The thermal expansion and contraction of solids can also have safety implications. For a given material the amount of its linear expansion, or contraction, in one direction is directly related to temperature and its original size (i.e. length, diameter, circumference). Thus ... 

A flexible hose must never be stretched tightly between two fittings. About 5 to 8 per cent of the total length must be allowed as slack to provide freedom of movement under pressure. When under pressure, flexible hose contracts in length and expands in diameter. Examples of correct and incorrect installations of flexible hose are illustrated in Figure 40.33. 

Snijders, J.G. and Pyykko, P. (1980) Is the relativistic contraction of bond lengths an orbital contraction effect Chemical Physics Letters, 75, 5-8. 

For this measurement, the sample was a Te02 optical quality crystal of 2 x 2 x 3 cm3, corresponding to a mass of 75.493 g. It was sustained by four pure tin cylinders, which kept the crystal blocked inside a copper frame, as shown in Fig. 12.5. The length of the cylinders was chosen to compensate the thermal contraction of the crystal, down to the lowest reached temperatures. 

Since the distance between the zeroes, in terms of sample length variation, is A/4, the total contraction of the sample is AL = N A/4, where N is the total number of zero crossing. The resolution of the system is basically A/4, but it could be improved with an evaluation of fractions of a fringe. 

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