em another team.
The concept of electrical current.
In the beginning of the 17th century Sir William Gilbert discovered that many substances could be electrified by friction. Gilbert named this effect "electric" after the word "electron" - the Greek name for amber. In 1756 the great Russian scientist M. V. Lomonosov was the first to make theoretical analysis of electrical phenomena. At present the nature of electrification is explained by the electron theory. According to the modern theory all matter is composed of atoms or tiny particles. Each atom consists of a nucleus, a small positively charged mass and a number of lighter negatively charged particles called electrons, which revolve around the nucleus. Normally each atom of a substance is electrically neutral, or it has equal amounts of negative and positive charges, i. e. produces no electrical current.
When an electric charge is at rest it is spoken of as static electricity, but when it is in motion it is refearred to as an electric current.
An electric current which flows in the same direction through a conductor or a current which does not change its polarity is called a direct current or a continuous current.
An alternating current flows first in one direction and then in the other.
Task 6. Read the dialogue in English and in Russian.
John: What does "electrified" mean?
Mr. Robertson: You can make electricity by rubbing two things together. You can also make electricity by putting substances like zinc and copper in some chemicals. And you can make electricity by putting a magnet to a wire. There are different ways of making electricity.
John: Is electricity the same as magnetism?
Mr. Robertson: No.
John: Is lightning electrici
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