UNIT 2: Great Scientific Experiments and Discoveries

Text 1

Ø Выпишите значения данных слов, пользуясь словарём; выучите их наизусть. Обратите внимание на их произношение:

Generating an Electric Current

The first method used in producing an electric current was chemical in nature. Credit for its discovery is given¹to an Ita­lian physician named Aloisio Galvani (1737–1798). One day while engaged in dissecting a frog, Galvani noticed the leg muscles contract whenever a nearby electric machine was in ope­ration. Further investigation showed the same twitching effect² to be obtained by simply connecting the nerve and muscle of the leg to dissimilar metals. But no such result was obtained if only one metal was used or if non-conductors were employed. There were obviously two possible sources of the phenomenon. Either the current was set up at the junction of the two metals or it was a property of the animal tissues³. Galvani favoured the latter view and in 1791 announced his discovery, attributing the current to what he called 'animal electricity' or as it came to be known, 'galvanism'. Galvani is an excellent example of a scientist who behaved most unscientifically with regard to a hypothesis which he himself had advanced. He became so pre­judiced in favour of his animal magnetism theory that it was quite impossible for him to view objectively later evidence which definitely contradicted it and finally caused it to be discarded.

Another Italian, Alessandro Volta (1745–1827), a professor of physics in the University of Pavia, established the true source of the electric current. He demonstrated that it could be produced by the action of dissimilar metals without the presence of animal tissue of any sort.

In the course of his experiments in 1800 he developed the first electric battery, a device known as a voltaic pile⁴. Although he tried a number of different materials he found that the best results were obtained when he used silver and zinc as the two metals. The pile consisted of a series of small discs of these and of cardboard, the latter having been soaked in a salt solution. Then he piled the discs up one on another in the order silver, zinc, cardboard, and so forth, ending with zinc. By connecting wires to the top and bottom discs he was able to get continuous electric currents which were of substantial size.

All the essentials of a modern electric cell or battery were present in the voltaic pile. Developments since that time have been largely directed toward making cells more convenient to use and toward eliminating various undesirable chemical reactions.

Примечания

1. credit for its discovery is given – честь его открытия принадлежит;

2. twitching effect – эффект сокращения мышц;

3. animal tissue – живая ткань;

4. a voltaic pile – вольтов столб (гальваническая батарея).

Задания по тексту "Generating an Electric Current"

I. Найдите в тексте английские эквиваленты для следующих слов:

генерировать, теория, объективно, профессор, физика, реакция, демонстрировать, цинк, соль, источник, противоречить, хотя, ткань, отказываться, существенный, устранять.

II. Ответьте на следующие вопросы, используя информацию из текста.

1. Was Aloisio Galvani a physician or a physicist? 2. What century did he live in? 3. Was Galvani a theoretician or an experimentator? 4. What did he investigate? 5. What made Galvani carry out experiments on electricity? 6. What methods did he use in his work? 7. What conclusions did he come to? 8. Did he claim that the problem he studied was solved? 9. Alessandro Volta was a professor of physics, wasn't he? 10. Did Volta live in the XVIIIth or XIXth century? 11. What is Volta famous for? 12. On the basis of what experiment did Volta manage to demon­strate the true source of the electric current? 13. What do you know about the construction of the first electric battery? 14. What is the difference between the first electric battery and a modern one and what have they in common?

III. Найдите в тексте слова, имеющие общий корень с нижеприведенными словами. Определите части речи, к которым они относятся, и переведите их.

a) discover, operate, investigate, conduct, act, differ, continue, develop, vary, react;

b) chemistry, science, magnet;

c) simple, similar, obvious, electric, scientific, definite, final.

IV. Вместо многоточия вставьте подходящие по смыслу слова из списка.

In 1791 Aloisio Galvani, an Italian ..., announced his ... which he called 'animal ...'. Another Italian, a professor of ... Alessandro Volta established the true ... of the electric current. During his experiments he developed the first electric ... .

He tried a number of different ... and found that the best ... were obtained with silver and ... . By connecting ... to the top and bottom disks Volta was able to get electric ... .

physics, current, results, wires, physician, source, electricity, discovery, battery, zinc, materials.

V. В предложениях отсутствует одно слово. Лишь один из четырех вариантов придает предложению правильное, логически осмысленное значение. Выберите правильный вариант.

1. The method of ... electricity directly from heat attracts attention of scientists all over the world.

1) ending, 2) producing, 3) eliminating, 4) directing.

2. More and more, we are discovering that all biological and ... processes are electrical in nature.

1) substantial, 2) possible, 3) chemical, 4) electrical.

3. It is a fundamental law that ... results from electricity in motion.

1) conduction, 2) solution, 3) magnetism, 4) battery.

4. A magnetic field ... around any conductor carrying a cur­rent, but the field exists only when the current is flowing.

1) is engaged in, 2) is investigated, 3) is favoured, 4) is set up.

VI. Выпишите из текста предложения, содержащие инфини­тив или инфинитивные конструкции. Переведите их на русский язык.

Text 2

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Faraday's Experiment

Faraday knew from his long study of electricity that magne­tism should be able to produce a current, as well as vice versa. In spite of his various failures, the idea of producing a current directly by magnetic action remained firm in his thoughts¹.One of his friends said later how at this period of his long life Fara­day used to carry about with him in his pocket a small rough model of electro-magnetic apparatus. This consisted simply of an inch-long straight iron rod, or core, with some turns of copper wire wound round it.

The basic idea he had in mind was this: if an electric current in a wire can produce a magnetic effect, why should not a magnet near a conducting wire produce an electric current? It was really a simple reversal of Oersted's 1820 discovery.

On August 29, 1831, Michael Faraday made his first success­ful experiment. Bya happy choice²,he decided to work not with a straight bar or even a horseshoe magnet, but with a ring. He made a soft iron ring, nearly an inch thick and six inches in external diameter. On opposite sides of this ring he had wound long coils of fine copper wire, separating each turn by string and each layer by calico, for insulation purposes. The ends of the left-hand coil he connected to his galvanometer three feet away³, while the ends of the right-hand coil were connected up to a bat­tery. When he switched on the battery circuit, there was imme­diately a slight reaction on the magnetic needle connected to the other coil. In his own words: "It oscillated and settled at last in its original position". On switching off the battery again, there was "a deflection of the needle", but while the so-called voltaic current was flowing through the wire there was no reaction on the galvanometer. This happened many times: each time the battery current came on, the needle linked to the opposite, uncon­nected coil deflected and then came to rest; each time the circuit was broken, the same effect was noticed.

Faraday was a little disappointed, having expected to get a positive deflection of the needle all the time his battery current was switched on. Instead he got it only when the magnetic field in the iron ring was changing – either switching on or switching off.

Nevertheless, he had produced electricity through magnetism, which had never been done before. There was no connection bet­ween the left-hand coil on the ring and the right-hand coil fed from the battery, nor was there any leakage of current from one side to the other. Yet as the galvanometer needle showed, electri­city, however weak, had flowed momentarily each time through the left-hand coil. It was new electricity where none existed be­fore, and it had been produced, or induced, by electromagnetism.

Примечания

1. remained firm in his thoughts – не оставляла его мыслей;

2. by a happy choice – по счастливой случайности;

3. three feet away – расположенный на расстоянии трех футов.

Задания по тексту "Faraday's Experiment"

I. Определите по суффиксам, какой частью речи являются нижеприведенные слова. Дайте русские эквиваленты этих производных:

electricity, magnetism, various, directly, magnetic, action, really, successful, nearly, insulation, immediately, reaction, origi­nal, position, deflection, unconnected, connection.

II. Основываясь на информации, полученной из текста, вы­разите свое согласие или несогласие с нижеприведенными утверждениями. Свое согласие выразите, начиная словами "That's right, according to the text...", несогласие – словами "That's wrong, according to the text...".

1. Faraday wanted to produce electricity by electromagne­tism. 2. A model of an electromagnetic apparatus he used to carry about him consisted of a horseshoe magnet and a straight bar with some turns of iron wound round it. 3. Michael Faraday made his first successful experiment together with Oersted. 4. Faraday worked neither with a straight bar, nor with a hor­seshoe magnet but with a ring. 5. Faraday wound long coils of fine copper wire on opposite sides of the ring. The turns were separated for insulation purposes. One coil was connected to a galvanometer and the other to a battery. 6. The needle on the galvanometer deflected only when the magnetic field in the iron ring was switching on or switching off. 7. Faraday failed to pro­duce electricity through magnetism.

III. Ответьте на следующие вопросы:

a) What does the author mean when he says that...

1. Faraday remained firm in his thoughts? 2. It was really simple reversal of Oersted's 1820 discovery? 3. By a happy choice Faraday decided to work with a ring?

b) 1. What was Faraday famous for? 2. Was he an English or a French scientist? 3. When did Faraday conduct his first successful experiment? 4. What device did he use in his experiment? 5. Can anybody repeat Faraday's experi­ment? 5. What is needed for repeating his experiment? 6. Why is Faraday's discovery considered to be very important?

IV. Составьте предложения о Фарадее и его эксперименте, используя слова и выражения, приведенные ниже:

1) an experiment, experimental, experimentally; 2) an experimentor (an experimental physicist); 3) to begin (to start) an experiment; 4) to be busy with an experiment; 5) to make (to carry out, to perform, to conduct) a set of experiments; 6) to experiment on something; 7) an experiment with (on) (light, rays); 8) the experiment is performed with an apparatus; 9) the experiment is concerned with (deals with); 10) the experiment shows (proves, determines, explains, gives information on) some­thing; 11) the experiment gives evidence for (against) something, 12) the experiment shows (proves, explains) that...; 13) the re­sults (the data) of an experiment enable us to determine (to esti­mate, to compute, to see) something; 14) to show (to prove, to obtain, to get, to find, to determine, to perform, to test) experi­mentally; 15) the experiment lasted (took) several days; 16) the experiment is completed (is over); 17) to make measurements during the experiment; 18) to take the readings of the apparatus; 19) to obtain the data (results); 20) to process the data obtained; 21) to classify the data (results); 22) to check up the results; 23) to compare (to make a comparison between) the results; 24) to analyse the results; 25) to sum up the data in tables; 26) to draw conclusions from experimental data; 27) on the basis of the experiment it was concluded that... .

V. Подготовьте рассказ, используя слова и выражения из
упражнения IV:

1) об эксперименте Фарадея, Герца, Вольты или какого-либо другого ученого;

2) об эксперименте, который вы сами проводили в лаборатории электричества.

Text 3

Ø Выпишите значения данных слов, пользуясь словарём; выучите их наизусть. Обратите внимание на их произношение: