Lesson three Oral topic: in the chemical laboratory Grammar

reading and discussing


Read the next texts and prove that observations often lead to the discoveries.
Vulcanization of Rubber (резина).
In February 1838 Charles Goodyear had a lucky accident when a mixture of sulfur and Indian rubber was brought carelessly into contact with a hot stove. He saw the mixture melt (плавиться) and react to form the product he had been trying to make for seven years. By this act and observation he discovered how to vulcanize rubber.


Crisis.
The combination of trial, observation, and deduction gives a method to meet changing conditions. Currently there is much talk of energy shortage (нехватка). The scientific method will probably help as it did in Pilgrim days. In 1615, James I of England found that his navy was short of wood and the supply was running out (запас истощался). He decreed that wood could no longer be used to stoke (поддерживать огонь) the glassmakers’ furnaces. This ruling seemed to mean the end of an industry. Actually, the glassmakers soon learned to use coal, an innovation at the time. But coal produced smoke and gases that were bad for the glass. A covered melting pot kept the smoke away from the molten glass and produced a bonus, higher temperature. This made it possible for George Ravens Сroft to make glass with a larger percentage of lead (свинец) oxide in it. His lead, or flint (кремень), glass was clearer and easier to carve and mold (резать и формовать). English glassmaking improved instead of dying.


Creating thermometer scales.
How do scientists such as Gabriel Fahrenheit and Anders Celsius create new concepts such as temperature scales? Many times, new discoveries stem from (происходить) a scientist` s personal interests or observations.
A cow` s normal body temperature is the same as a human` s – about 98.6° F. Yet some evidence indicates that Fahrenheit based his primary reference point for 100° F on the body temperature of a cow. If this story is true, the Fahrenheit scale was based on a sick cow! Some have claimed (утверждать) that Fahrenheit chose his value of 100° F so that the normal human body temperature would be 98.6° F, but this cannot be the case. While most people were aware (знать) that there was a normal human body temperature, its value was not determined until after the development of the thermometer scales. Instead, it seems that Fahrenheit based his scale on a measurement of interest to him.
Anders Celsius was a Swedish astronomer who had an interest in determining exactly how cold the Swedish night were as he walked to his observatory. Celsius wanted to know how warmly to dress and whether the metal telescope parts would be too cold to use in gazing at the vastness of the heavens (вглядываясь в безбрежное небо). The Celsius scale grew out of these practical concerns.
As you can see, scientists often have the same kinds of problems nonscientists do. Sometime, scientists view (рассматривать) those problems as an impetus (движущая сила, толчок) to study new ideas and invent new solution.

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