Text A

Nuclei and particles

(from the history of physics)

Although speculation on the nature of matter appears at the very dawn of Greak philosophy, a scientific study of this subject, in the modern sense, was initiated in the sixteenth century, when experiment and mathematic analysis were first used in conjunction with each other.

Detailed knowledge of atomic struc­ture was acquired only in 1910. But the first experimental discoveries that made possible an attack on the structure of the atom followed each other in rapid succession.

In 1895 Roentgen discovered X-rays; early in 1896 Becquerel discovered radioactivity, and a little later Sir J. J. Thomson gave proof of the independent existence of the negative electron. These were soon followed by the introduction into physics of the idea of quanta of energy. Einstein's special theory of relativity (1905) formed the foundation on which modern physics rests.

Maria Curie observed that although the radioactivity of uranium compounds, taken from pure chemicals, was proportional to the uranium content, the ores from which they were extracted showed much more radioactivity than could be accounted for by the uranium content alone. She then performed chemical analyses of the ores and measured the radioactivity of isolated fractions. This method led to the discovery of polo­nium and radium.

Surprise followed surprise when it was found the radioactive atoms changed their chemical identity with time. Intense study of the phenomenon led to the theory of radioactive decay developed by Rutherford in 1903.

Revision exercises

I. Translate the following sentences paying attention to the Modal Verbs.

1. The engineers are to study the problem of using cosmic rays and solar energy. 2. Scientists had to pay more attention to the researches, principally in the field of nuclear physics. 3. The engineers of our plant will be able to widen the field of application of teleautomation. 4. One should note that comprehensive research on nuclear energy is under way in our country. 5. The scientists will have to create new and more reliable instruments.

II. Translate the following sentences into Ukrainian to the equivalents of the Modal Verbs.

1. Chemists have to create the materials that do not exist in nature. 2. Without a computer scientists will not be able to solve complicated problems. 3. You should take into consideration the results of our experiments. 4. The workers were to assemble the machine yesterday. 5. The engineer has to use new technological processes. 6. The electronic devices will have to ensure regular production processes. 7. The engineer from our plant is to take part in this conference. 9. Are you able to make this experiment once again? 10. At present our engineers are to develop the most advanced methods of production.

III. Translate the sentences, pay attention to the functions of the Verb "to be".

1. When a structure or a machine is to be built, suitable materials are to be chosen for the parts. 2. Every element is made up of minute particles, which are called atoms. 3. Burning is simply the combination of a substance with oxygen in the air. 4. One of the great problems of the mechanical engineer is to eliminate friction in a machine. 5. It is the cyclotron that can be used to produce very high speed positively charged particles of enormous energy. 6. A study of the motions of the objects is necessary if we are to understand them and to learn to control them. 7. Many important observations are being made by our cosmonauts. 8. Every large industry has research laboratories where there are many opportunities to observe the experiments which are being performed. 9. A great number of new blocks of flats were built in our city. 10. Automation is finding wider application in all branches of industry.