Classifying Materials

 

There are many ways of classifying materials. The one we shall use here is based on the ability of a material to conduct electricity. It is known that conduction takes place as a result of the motion of charged particles, usually electrons. The ability of any material to conduct electricity is directly proportional to the number of charged particles inside the material that can be set in motion. Materials (for example metals), that have relatively large numbers of free electrons, readily conduct electric current and are called conductors. Other materials having very few (or no) free electrons do not readily conduct electric current under normal conditions (óñëîâèå) and are called insulators. It should be realized that the terms 'conductor' and 'insulator' are not absolute, that is2 some conductors do not conduct as well as other conductors, while some insulators do not insulate as well as other insulators.

Notes

1. it should be realized — ñëåäóåò ó÷åñòü

2. that is — òî åñòü