Text 5

Text 1

Pre-reading practice:

1. What do you know of the achievements of Russian scientists into world science.

2. Do you know what was the most outstanding invention of A.S.Popov.

A GREAT INVENTION OF A RUSSIAN SCIENTIST Radio occupies one of the leading places among the greatest achievements of modern engineering. It was invented by Professor A. S. Popov, a talented Russian scientist, who demonstrated the first radio – receiving set in the world on May 7, 1895. And it is on this day that the anniversary of the birth of the radio is marked. By his invention Popov made a priceless contribution to the development of world science. A. S. Popov was born in the Urals, on March 16, 1859. For some years he had been studying at the seminary in Perm, and then went to the University of St. Petersburg. In his student days he worked as a mechanic at one of the first electric power – plants in St. Petersburg which was producing electric lights for Nevsky Prospekt. After graduating from the University in 1882, A. S. Popov remained there as a post – graduate at the Physics Department. A year later he became a lecturer in Physics and Electrical Engineering in Kronstadt. By this time he had already among specialists as an authority in this field. After Hertz had published his experiments proving the existence of electromagnetic waves, A. S. Popov thought of the possibility of using Hertz waves for transmitting signals over a distance. Thus the first wireless (radio) receiving set was created. Then Popov developed his device and on March 24,1896 he demonstrated the transmission and reception of a radiogram consisting of two words: Heinrich Hertz. On that day the radio-telegraphy was converted from an abstract theoretical problem into a real fact. Popov’s invention laid the foundation for further inventions and improvements in the field of radio engineering. Since that time scientists all over the world have been developing the modern systems of radiotelegraphy, broadcasting, television, radiolocation, radio-navigation and other branches of radio-electronics.

Practice 1. Re-read the text and answer the questions.

1. Who was radio invented by?

2. What do you know about A.S.Popov’s early life?

3. Whose research helped him to make his invention?

4. When did he develop his device?

5. What was contribution of his invention to the world science?

Practice 2. Give the Russian equivalents to the word-combinations from the text:

- to occupy one of the leading places;

- radio engineering;

- a priceless contribution;

-to gain recognition;

- electromagnetic waves;

- transmitting signals over a distance;

- to lay the foundation for further inventions and improvements;

- branches of radio-electronics.

Practice 3. Match up the words with their definitions.

achievement развитие

invention вклад

contribution радио

development изобретение

existence достижение

wireless существование

Practice 4. Complete the sentences using the words from the table:

After Hertz had published his experiments	have been developing the modern systems of radio-electronics.
By his invention Popov made a priceless contribution	at one of the first electric power – plants.
In his student days he worked as a mechanic	A. S. Popov thought of the possibility of using Hertz waves for transmitting signals over a distance.
Since that time scientists all over the world	to the development of world science.

Practice 5. Complete the table:

Verb	noun	adjective or participle
	achievement
Exist
		marked
Receive

Text 2

Pre-reading practice:

1.What do you know about the nature of electricity?

2. Do you agree that all matter is electrical in nature?

THE NATURE OF ELECTRICITY

Practical electricity is produced by small atomic particles known as electrons. It is the movement of these particles which produce the effects of heat and light.

The pressure that forces these atomic particles to move, the effects they encounter opposition and how these forces are controlled are some of the principles of electricity.

Accepted atomic theory states that all matter is electrical in structure. Any object is largely composed of a combination of positive and negative particles of electricity. Electric current will pass through a wire, a body, or along a stream of water. It can be established in some substances more readily than in others, that all matter is composed of electric particles despite some basic differences in materials. The science of electricity then must begin with a study of the structure of matter.

Matter is defined as any substance which has mass (or weight) and occupies space. This definition should be broad enough to cover all physical objects in the universe. Wood, water, iron, and paper are some examples of matter. Energy is closely related to, but not to be confused with, matter. Energy does not have mass, and it does not occupy space. Heat and light are examples of energy.

The smallest particle of matter which can be recognized as an original substance was thought to be a unit called the atom. Recently scientists have found particles even smaller than atoms, but our theories are still based on the atom. The atom consists of a nucleus and a cloud of electrons. It is generally agreed that the electrons are small particles of electricity, which are negative in nature. These particles orbit the nucleus in much the same fashion that planets orbit a sun.

Practice 1. Re-read the text and answer the questions.

1.What produces the effect of heat and light?

2. What are some of the principles of electricity?

3. What does accepted atomic theory state?

4. What are some examples of matter?

5. Does atom consist of a nucleus and a cloud of electrons?

Practice 2. Give the Russian equivalents to the word-combinations from the text:

-atomic particles;

-to be composed of;

-basic differences;

-structure of matter;

-to occupy space;

-physical objects;

-cloud of electrons;

-to orbit the nucleus.

Practice 3. Match up the words with their definitions

movement тепло

pressure материя

encounter давление

matter поток

stream сталкиваться

heat движение

Practice 4. Complete the sentences using the words from the table:

Matter is defined as any substance	and it does not occupy space.
The science of electricity then must begin with	was thought to be a unit called the atom.
The smallest particle of matter which can be recognized as an original substance	a study of the structure of matter.
Energy does not have mass,	which has mass (or weight) and occupies space.

Practice 5. Complete the table:

Verb	noun	adjective or participle
		practical
produce
		occupied
	heat

Text 3

Pre-reading practice: 1. What do you know about polarity?2. What do you think the text is about(what information it may present)? POLARITY All matter is basically composed of two types of electricity: positive particles and negative particles. The negative particles are relatively light in weight and in constant motion. These orbiting particles exhibit equal and opposite electrical characteristics to the heavier particles within the nucleus. When an atom has the same number of electrons as it has protons, it exalts no outward electrical properties. This is because the positive and negative charges are exactly balanced. Such an atom is electrically stable and is said to be neutral. When an atom takes on an excess of electrons, it exhibits outward characteristics similar to the electron. It takes an overall negative property. This condition is called a negative change, and such changed atom is not electrically stable. A charged atom is called an ion, and if the charge is negative, it is called a negative ion. An atom which has less than its normal quota of electrons, displays a positive polarity similar to that of the proton due to the fact that it has more positive protons than it has negative electrons. This type of atom is said to assume a positive electrical charge. Such an atom is known as a positive ion while it is in this electrically unstable condition. These charges of atoms are the simplest examples of static electricity. We stated that atoms are influenced to accept or give up electrons. As the name dynamic electricity indicates, this is electricity in motion.The heart of the matter is electron movement. In electrical system, electrical pressure is needed. To maintain this pressure, a device that will move electrons in a way similar to that in which the pump moves water is necessary. The most familiar is the storage battery.

Practice 1. Re-read the text and answer the questions.

1.What two types of electricity do you know?2. Are positive and negative charges balanced?3. What happens when an atom takes on an excess of electrons?4. When does an atom display a positive polarity?5. What is dinamic electricity?

Practice 2. Give the Russian equivalents to the word-combinations from the text:

-constant motion;-orbiting particles;-exalt properties;-exhibit outward characteristics;-less than normal;-storage battery;

Practice 3. Match up the words with their definitions:

excess благодаря

similar условие

condition похожийdue to означатьindicate избыток

Practice 4. Complete the sentences using the words from the table:

These charges of atoms	displays a positive polarity similar to that of the proton.
An atom which has less than its normal quota of electrons,	it exhibits outward characteristics similar to the electron.
As the name dynamic electricity indicates	are the simplest examples of static electricity.
When an atom has the same number of electrons as it has protons	this is electricity in motion.

Practice 5. Complete the table:

Verb	noun	adjective or participle
		electrical
indicate
maintain
	influence

Text 4

Pre-reading practice:

Does the electric current flow through all matters?

2. Where does the electric current find wide application?

ELECTRIC CURRENT The electric current is a quantity of electrons flowing in a circuit per second of time. The unit of measure for current is ampere. If one coulomb passes a point in a circuit per second then the current strength is 1 ampere. The symbol for current is I. The current which flows along wires consists of moving electrons. The electrons move along the circuit because the e.m.f. drives them. The current is directly proportional to the e. m. f. In addition to traveling through solids, however, the electric current can flow through liquids as well and even through gases. In both cases it produces some most important effects to meet industrial requirements. Some liquids, such as melted metals for example, conduct current without any change to themselves. Others, called electrolytes, are found to change greatly when the current passes through them. When the electrons flow in one direction only, the current is known to be d. c., that is, direct current. The simplest source of power for the direct current is a battery, for a battery pushes the electrons in the same direction all the time (i.e., from the negatively charged terminal to the positively charged terminal). The letters a. c. stand for alternating current. The current under consideration flows first in one direction and then in the opposite one. The a. c. used for power and lighting purposes is assumed to go through 50 cycles in one second.One of the great advantages of a. c. is the ease with which power at low voltage can be changed into an almost similar amount of power at high voltage and vice versa. Hence, on the one hand alternating voltage is increased when it is necessary for long-distance transmission and, on the other hand, one can decrease it to meet industrial requirements as well as to operate various devices at home. Although there are numerous cases when d. c. is required, at least 90 per cent of electrical energy to be generated at present is a. c. In fact, it finds wide application for lighting, heating, industrial, and some other purposes.

Practice 1. Re-read the text and answer the questions.

1. What is the electric current?

2. Is ampere a unit of measure for current or e.m.f?

3. Why do electrons move along the circuit?

4. Where can electric current flow?

5. What is one of the great advantages of the alternating current?

Practice 2. Give the Russian equivalents to the word-combinations from the text:

- unit of measure;

- to flow along wires;

- in addition to;

- to meet industrial requirements;

- melted metals;

- source of power;

- direct current;

- alternating current;

- under consideration.

Practice 3. Match up the words with their definitions

circuit жидкость

move преимущество

liquid противоположный

change цепь

opposite изменение

advantage двигаться

Practice 4. Complete the sentences using the words from the table:

One of the great advantages of a. c. is the ease	at least 90 per cent of electrical energy to be generated at present is a. c.
In addition to traveling through solids,	with which power at low voltage can be changed into an almost similar amount of power at high voltage and vice versa.
The letters a. c. stand for	the electric current can flow through liquids as well and even through gases.
Although there are numerous cases when d. c. is required	alternating current.

Practice 5. Complete the table:

Verb	noun	adjective or participle
	opposition
Move
	consideration
		changeable

Text 5.

Pre-reading practice:

What can you say about the effect of the electric current?
What effect is the most important in your opinion?

EFFECTS PRODUCED BY A CURRENT The current flow is detected and measured by any of the effects that it produces. There are three important effects accompanying the motion of electric charges: the heating, the magnetic, and chemical effects, the latter is manifested under special conditions. The production of heat is perhaps the most familiar among the principal effects of an electric current. The heating effect of the current is found to occur in the electric circuit itself. It is detected owing to an increase in the temperature of the circuit. This effect represents a continual transformation of electric energy into heat. For instance, the current which flows through the filament of an incandescent lamp heats that filament to a high temperature. The heat produced per second depends both upon the resistance of the conductor and upon the amount of current carried through it. The thinner the wire is, the greater the developed heat is. On the contrary, the larger the wire is, the more negligible the heat produced is. Heat is greatly desirable at times but at other times it represents a waste of useful energy. It is this waste that is generally called "heat loss" for it serves no useful purposes and decreases efficiency. The heat developed in the electric circuit is of great practical importance for heating, lighting and other purposes. Owing to it people are provided with a large number of appliances, such as: electric lamps that light our homes, streets and factories, electrical heaters that are widely used to meet industrial requirements, and a hundred and one other necessary and irreplaceable things which have been serving mankind for so many years. The electric current can manifest itself in some other way. It is the motion of the electric charges that produces the magnetic forces. A conductor of any kind carrying an electric current, a magnetic field is set up about that conductor.This effect exists always whenever an electric current flows, although in many cases it is so weak that one neglects it in dealing with the circuit. An electric charge at rest does not manifest any magnetic effect. The use of such a machine as the electric motor has become possible owing to the electromagnetic effect. The last effect to be considered is the chemical one. The chemical effect is known to occur when an electric current flows through a liquid. Thanks to it a metal can be transferred from one part of the liquid to another. It may also effect chemical changes in the part of the circuit comprising the liquid and thetwo electrodes which are found in this liquid. Any of the above mentioned effects may be used for detecting and measuring current.

Practice 1. Re-read the text and answer the questions.

1. What are three important effects accompanying the motion of electric charges?2. How is the heating effect of the current detected?3. What is heat loss?4. What is the other way of the electric current manifestation?5. When does the chemical effect of the electric current occur?

Practice 2. Give the Russian equivalents to the word-combinations from the text:

- to be detected and measured by;

- electric charges;

- heating effect;

- amount of current;

- heat loss;

- to be provided with;

- to produce the magnetic forces;

- electromagnetic effect.

Practice 3. Match up the words with their definitions

charge снабжать

occur происходить

heat незаменимый

resistance незаменимый

provide сопротивление

irreplaceable тепло

Practice 4. Complete the sentences using the words from the table:

The chemical effect is known to occur	whenever an electric current flows.
The production of heat is perhaps the most familiar	when an electric current flows through a liquid.
This effect exists always	is of great practical importance for heating, lighting and other purposes.
The heat developed in the electric circuit	among the principal effects of an electric current.