II. Выполните упражнения

1. Ответьте на вопросы.

1. What was the very first solid material that man began to use? 2. What did natural ceramics provide man with? 3. Why was ceramics used in a variety of applications? 4. Why did man get interested in ceramics so much? 5. What is ceramics? 6. What is a main characteristic of the construction of ceramics crystals? 7. Why are the ceramic materials so strongly resistant? 8. What are the principal elements in natural clays? 9. What does the construction of ceramic materials depend on? 10. Why are ceramic materials mass produced? 11. Why is the ceramic industry so important?

2. Откройте скобки, использую правильную форму глагола и переведите предложения.

1. Last year our plant (produced, produces) many ceramic goods which (are used, were used) widely. 2. At first man (baked, has baked) vessels of clay in the sun. 3. Recently ceramic compounds (are used, have been used) even in making steel. 4. Numerous analyses (have been carried out, had been carried out) before they stated the exact composition of this compound. 5. Now many scientists (are working, work) at the investigation of the new properties of ceramics. 6. Many new discoveries (took place, have taken place) since the last century. 7. Last week they (analysed, analyse) crystal structure of those new materials by means of X-ray diffraction. 8. For many years considerable work (has been carried out, was carried out) to convert ethylene into motor fuel. 9. Many beautiful articles made of ceramics (provided, provides) man with tools even in ancient time.

3. Переведите предложения из Active в Passive и наоборот. Перевести их на русский язык.

1. Physics and chemistry are taught by pupils in senior forms.

2. They appointed him Rector two years ago. 3. Almost all branches of chemistry will be enriched by this new theory. 4. This problem is being discussed by many scientists in our country . 5. We didn’t use this substance in our experiment because of its many impurities. 6. The scientists have noted the ability of chlorine dioxide to react with water. 7. An atom is observed by chemists as the smallest particle of any substance.

4. Составьте 10 предложений на английском языке, используя слова из активного словаря.

5. Составьте план пересказа текста и напишите по 2-3 предложения к каждому пункту.

III. Control Text

Прочитайте и переведите текст.

An iron rod held in the fire long enough increases in energy content until it becomes too hot to hold in the unprotected hand. Nevertheless the rod is still iron, and when cooled to its original temperature, its properties are just as the were before.

The heating and the subsequent cooling of the rod are examples of physical changes.

A physical change may result in a more or less temporary alteration of a few of the properties of a substance involved, but no change of composition results from it and most of the altered properties usually regain their former value.

Changes of this type are numerous and many of them are familiar to everyone. As an example we may take the behavior of ice when its heated.

At first when heated the ice melts, when further heated, the liquid water boils forming the gaseous water (or the steam, as its usually called). If the steam is cooled, the process is reversed – when cooled sufficiently, the ice result. The substance present in every instance was water. This experiment shows that there are three physical states in which the substance may exist.

If the rod concerned is placed in a container of hydrochloric acid, it will be noted that bubbles begin to form on the rod. If the rod involved is left in the acid for some time, the evolution of gas will continue. When examined, it will be found that the rod has diminished in mass or disappeared altogether. The liquid in the container if examined will have a greenish colour.

If evaporated, a mass of greenish crystals will be obtained. The crystals will have totally different properties. This is an example of a chemical change. So, a chemical change may be called a chemical reaction or simply a reaction, the substances entering into a chemical reaction are called reactants.

Phenomena accompanied by radical changes of substances are called chemical phenomena.

Объясните разницу между физическими и химическими превращениями на английском языке.

A chemical change is a change that takes place in a substance, during which it breaks up into simpler substances or it combines with other substances to make a new one with different properties or characteristics. For example, mercuric oxide may be changed to mercury and oxygen by heating it; the burning of wood is an example of a chemical change in which the elements carbon and oxygen are combined to form the gas, carbon dioxide. A physical change is one in which the identifying characteristics or properties of the substance are not changed although a change in form or state may occur. The melting of ice, the breaking of glass, or the dissolving of sugar in water are examples of physical changes.