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6 2, - . 250.00 .


6 2

: 2012


I. .


Speaking about crystals one often imagines something beautiful, perfect and rare. In reality, however, practically all solid bodies around us are crystals. The exceptions are plants, animals, water and the atmosphere".

Till recently, crystallography was regarded as "the most dreary, the most difficult, and the most useless of sciences”. Today crystallography is one of the most important branches of natural science, rich in practical achievements, having deep philosophical content. It is closely related to mathematics.

By now several thousand inorganic and over five thousand organic crystal structures have been studied.

Not long ago only X-rays* were used for structural analysis. And now the method of neutron diffraction has come into wide use in the field of crystal analysis.

Crystals offer a simple way for transforming one kind of energy into another, for instance, by using the action of light to obtain an electric effect, or to achieve optical effects by mechanical action. It is possible to illuminate a crystal with red light and make it emit green rays, In fact, in modern technology all the instruments that can emit energy are built around crystals.

Of special interest is research into the strength of crystals. All metals and alloys constitute a collection of variously placed tiny crystals. The more perfect the crystals, the higher the strength of the metal. This means that by special methods it is possible to obtain crystals of required strength.

II. . .

1. What kinds of matter are not crystals?

2. What branch of science does crystallography belong to?

3. What science is crystallography closely related to?

4. What methods are used for crystal analisis?

5. What crystals do all metals all alloys cousist of?