9. Define the type of conditional sentences. Translate them

а) 1.If a solid body or a liquid is heated, it will usually expand. 2. In case the temperature is raised, the reaction will proceed more rapidly. 3. The measurements were always correct provided the necessary instruments were used.

b) 1.If mercury did not expand when heated, it would not be used for taking temperatures. 2. Provided all the requirements were met, we should increase the efficiency of the engine. 3. But for electricity little could be done in a modern research laboratory.

c) 1. If they had completed the research, the results would have been discussed at the conference. 2. Provided the operator's cabin had been equipped with remote control, he would have been able to work faster and with grea­ter precision. 3. The manned spaceships might not have been launched into the cosmos unless scientists had studied the information received from the space satellites.

9. Speak about electric current

UNIT27. JAMES PRESCOTT JOULE

1. Memorize the following words:

brewer – пивовар

to be tutored – навчатися вдома (у репетитора)

servant – слуга

to quantify – визначати кількість

to estimate – оцінювати

to announce – оголосити, оповістити

feasibility – здійснення, виконання

magnitude – величина

convertibility – перетворення, обернення

to dissipate – розсіювати

to rotate -обертати, крутити

2. Translate the following international words without a dictionary

Electric, shock, effect, mechanical, equivalent, association, thermodynamics, hobby, cylinder, experimentation, manager, critics, motor, demonstration, fact, magnetism, kinetic, theory, philosophy, presentation

3. Read and translate the text:

James Prescott Joule was an English physicist and brewer, born in Salford, Lancashire. Joule was tutored at home in Salford until 1834 when he was sent, with his elder brother Benjamin, to study with John Dalton at the Manchester Literary and Philosophical Society. Joule was fascinated by electricity. He and his brother experimented by giving electric shocks to each other and to the family's servants. In 1843 he published results of experiments showing that the heating effect he had quantified in 1841 was due to generation of heat in the conductor and not its transfer from another part of the equipment.

Further experiments and measurements by Joule led him to estimate the mechanical equivalent of heat to raise the temperature of a pound of water by one degree Fahrenheit. He announced his results at a meeting of the chemical section of the British Association for the Advancement of Science in Cork. In 1838, his first scientific papers on electricity were contributed to Annals of Electricity. Joule studied the nature of heat, and discovered its relationship to mechanical work. This led to the theory of conservation of energy, which led to the development of the first law of thermodynamics. Joule became a manager of the brewery and took an active role until the sale of the business in 1854. Science was a hobby but he soon started to investigate the feasibility of replacing the brewery's steam engines with the newly-invented electric motor. Joule started to seek a purely mechanical demonstration of the conversion of work into heat. By forcing water through a perforated cylinder, he was able to measure the slight viscous heating of the fluid. The facts that the values obtained both by electrical and purely mechanical means were in agreement to at least one order of magnitude was, to Joule, compelling evidence of the reality of the convertibility of work into heat. Later he measured the heat generated against the work done in compressing a gas. This experiment offered the easiest target for Joule's critics but Joule disposed of the anticipated objections by clever experimentation. However, his paper was rejected by the Royal Society and he had to be content with publishing in the Philosophical Magazine. Also in 1847, another of Joule's presentations at the British Association in Oxford was attended by George Gabriel Stokes, Michael Faraday, and William Thomson, later to become Lord Kelvin, who had just been appointed professor of natural philosophy at the University of Glasgow. He worked with Lord Kelvin to develop the absolute scale of temperature, made observations on magnetism, and found the relationship between the current through a resistance and the heat dissipated, now called Joule's law. On the measure of moving force, Joule perceived the relationship between his discoveries and the kinetic theory of heat. His laboratory notebooks reveal that he believed heat to be a form of rotational, rather than translational motion. The unit of energy, the joule, is named after him.