Conduction of electricity

Unit 3

ELECTRICITY

Active Vocabulary

charge

direct current (DC)

alternating current (AC)

solid

liquid

flow

Tunung-in

Task 1 Discuss the questions using your knowledge of physics.

1) What is electricity?

2) What determines the conduction of electricity?

3) Why are metals good conductors? Which are the best conductors?

4) Do gases conduct electricity?

5) What are the different types of electricity?

6) What is a major advantage of AC electricity?

Reading I

Basics of Electricity

Task 2 You are going to read the text about electricity. Seven sentences have been removed from it. Choose from sentences A-G the one which fits each gap (1-7). There is an example at the beginning. Then check your answers to the questions of Task1.

A Gases are not good conductors of electricity because of the distances between atoms.

B This is the type of electricity that comes from the outlets in most homes.

C This flow of electrons through the conductor is electricity.

D Often the electrons are pulled from the atoms on one surface and allowed to collect on the surface of another material.

E It has the advantage of being able to have its voltage easily changed to a higher or lower level.

F The conduction of those electrons is determined by the type of material.

G This allows free electrons to roam about the material.

Electricity is the movement of free electrons in a material toward an area of positive (+) charges. 1_ G _____ (The conduction of those electrons is determined by the type of material.) Some conduct well, while other materials prevent the movement of electrons. Electricity can take the form of static electricity, direct current (DC) electricity, or alternating current (AC) electricity.

Conduction of electricity

Solid metals are good conductors of electricity, because electrons are allowed to move freely throughout the material. In the solid state, the atoms of metals are held in place and only vibrate. 2 ____ Copper and gold are some of the best conductors of electricity. Although iron is a good conductor, iron oxide (rust) is not.

In semi-conductors—such as materials used in computer chips—the electrons have limitations to their movement, such as only being allowed to move in one direction or in one plane.

Nonconductors inhibit the movement of electrons within the material. But they often do allow electrons and ions to collect on their surfaces. Examples of nonconductors or electrical insulators are: plastic, rubber, glass, most metal oxides (like rust), air, oil, pure de-ionized water. 3 ____ Electrons have difficulty moving through gases, unless the gas is ionized or heated to higher temperatures.

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