In the second mode of working, the crystal fibre uses the regular array of holes to influence light in much the same way as the arrangement of atoms in a crystal can determine whether electrons are able to travel easily through it and hence whether the crystal is electrically conducting or not.

ECONOMIST: A new approach to making optical fibres

Phonics teaching is an important component of the teaching of reading, but not all words in English are phonically regular (the linguist David Crystal estimates 80% are, but the other 20% contains many of the most common words in English).

BBC: Viewpoints: Teaching children to read

Quartz watches use very high-frequency oscillations of a crystal, which can be tuned with extreme precision to produce regular signals.

ECONOMIST: A luxury watchmaker is putting silicon in its timepieces

For example, she cleans the kitchen sink with used tea leaves instead of regular detergent (less polluting and no extra cost), and polishes the crystal with a solution of soap and vinegar.

CNN: JAPAN'S DOWNSIZING FABLE

This fantastic plastic has molecules far longer than those of regular polyethylene, and these molecules are, in addition, packed tightly into a crystal structure rather than being scattered at random.

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