Conversation. Working on the text

Ex.5. Pronounce the words correctly:

to assume, astronomer, to revolve, eclipse, Earth-centered, astronomy, huge, telescope, to orbit, convinced, to exert, analysis, satellite, ellipse, focus, foci, comet, revolution, orbital, equal, mathematical, relationship, mean, ratio, cube, average.

Ex.6. Read and translate the following text. Divide it into logical parts. Entitle each of these parts:

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Planetary motion and gravitation

Since ancient times, the Sun, Moon, planets, and stars had been assumed to revolve around the Earth. Nicholas Copernicus, a Polish astronomer, noticed that the best available observations of the movements of planets and stars did not fully agree with the Earth-centered model. The results of his many years of work were published in 1543, when Copernicus was on his deathbed. His book showed that the motion of planets is much more easily understood by assuming that the Earth and other planets revolve around the Sun.

Tycho Brahe was born a few years after the death of Copernicus. As a boy of 14 in Denmark, Brahe observed an eclipse of the Sun on August 21, 1560, and vowed to become an astronomer. Tycho Brahe studied astronomy as he traveled throughout Europe for five years. He did not use telescopes. Instead, he used huge instruments that he designed and built in his own shop on the Danish island of Hven. He spent the next 20 years carefully recording the exact positions of the planets and stars. Brahe concluded that the Sun and the Moon orbit the Earth and that all other planets orbit the Sun.

Johannes Kepler, a 29-year-old German, became one of Brahe’s assistants when he moved to Prague. Upon his death in 1601, Kepler inherited 30 years’ worth of Brahe’s observations. He studied Brahe’s data and was convinced that geometry and mathematics could be used to explain the number, distance, and motion of the planets. Kepler believed that the Sun exerted a force on the planets and placed the Sun at the center of the system.

After several years of careful analysis of Brahe’s data on Mars, Kepler discovered the laws that describe the motion of every planet and every planet satellite. Kepler’s first law states that the paths of the planets are ellipses, with the Sun at one focus. An ellipse has two foci. Like planets and stars, comets also orbit the Sun in elliptical orbits. Comets are divided into two groups: long-period comets and short-period comets, based on orbital periods, each of which is the time it takes the comet to complete one revolution. Long-period comets have orbital periods longer than 200 years, and short-period comets have orbital periods shorter than 200 years. Comet Hale-Bopp, with a period of 2400 years, is an example of a long-period comet. Comet Halley, with a period of 76 years, is an example of a short-period comet.

Kepler found that the planets move faster when they are closer to the Sun and slower when they are farther away from the Sun. Thus, Kepler’s second law states that an imaginary line from the Sun to a planet sweeps out equal areas in equal time intervals. Kepler also found that there is a mathematical relationship between periods of planets and their mean distances away from the Sun.

Kepler’s third law states that the square of the ratio of the periods of any two planets revolving about the Sun is equal to the cube of the ratio of their average distances from the Sun. Thus, if the periods of the planets are T_A and T_B, and their average distances from the Sun are r_A and r_B,

Note that the first two laws apply to each planet, moon, and satellite individually. The third law, however, relates the motion of several objects about a single body. For example, it can be used to compare the planets’ distances from the Sun to their periods about the Sun. It also can be used to compare distances and periods of the Moon and artificial satellites orbiting Earth.

Ex.7. Translate the following word combinations and parts of the sentences into Russian:

since ancient times; to revolve around the Earth; did not fully agree with the model; the results of his many years of work; on his deathbed; observed an eclipse of the Sun; as he traveled throughout Europe for five years; carefully recording; the exact positions of the planets and stars; the Sun and the Moon orbit the Earth; 30 years’ worth of Brahe’s observations; to explain the number, distance, and motion of the planets; the Sun exerted a force on the planets; after several years of careful analysis; the motion of every planet and satellite; the paths of the planets; long-period comets; short-period comets; orbital period; sweeps out equal areas in equal time intervals; a mathematical relationship; mean distance; the square of the ratio of the periods; average distance; the first two laws apply to each planet, moon, and satellite individually; artificial satellites.

Ex.8. Translate the definitions into Russian. Find in the text terms defined by these definitions:

1. the scientific study of the Sun, the earth, the Moon, stars, planets, etc.;

2. a natural object that moves around a larger natural object in space;

3. the amount of space between two thing or places;

4. a complete circular movement around the point, especially of one planet around another;

5. a simple description of a system, used for explaining how smth. works or calculating what might happen, etc.;

6. to go in a circle around the central point;

7. a mass of dust and ice that moves around the Sun and looks like a bright star with a tail;

8. an occasion when the Moon passes between the Earth and the Sun so that you cannot see all or a part of the Sun for a time;

9. a large round object in space that moves around a star (such as the Sun) and receives light from it;

10. a large ball of burning gas in space that we see as a point of light in the sky at night;

11. a curved path followed by a planet or an object as it moves around another planet, star, etc.

Ex.9. Answer the following questions:

1. What did ancient people assume concerning the Sun, the Moon, planets and stars?

2. Was Nicholas Copernicus a Polish astronomer or a Czech mathematician?

3. When were the results of his many years of work published?

4. Nicholas Copernicus assumed that the Earth and other planets revolve around the Sun, didn’t he?

5. Tycho Brahe observed an eclipse of the Sun on August 21, 1560, didn’t he?

6. How long did T. Brahe study astronomy as he traveled throughout Europe?

7. What did T. Brahe conclude after having carefully recorded the exact positions of the planets and stars?

8. Who inherited 30 years’ worth of T. Brahe’s observations?

9. J. Kepler believed that the Earth exerted a force on the planets and placed the Earth at the center of the system, didn’t he?

10. What does Kepler’s first law state?

11. According to Kepler’s ideas Comets are divided into two groups (long-period comets and short-period comets), aren’t they?

12. Is a famous Comet Halley with a period of 76 years an example of a short-period comet?

13. What does Kepler’s second law state?

14. What does Kepler’s third law state?

Ex.10. Agree or disagree with the following statements:

1. A famous Polish astronomer Nicholas Copernicus noticed that the best available observations of the movements of planets and stars fully agree with the Earth-centered model;

2. The results of his many years of work were published when Copernicus was on his deathbed;

3. Tycho Brahe observed an eclipse of the Sun on July 12, 1560.

4. T. Brahe used huge instruments that he designed and built in his own shop on the Danish island of Hven.

5. T.Brahe spent about 30 years carefully recording the exact positions of the planets and stars.

6. T. Brahe concluded that the Sun and the Moon orbit the Earth and that all other planets orbit the Sun.

7. Upon the death of N. Copernicus in 1543 J. Kepler inherited 30 years’ worth of his observations.

8. J. Kepler studied Brahe’s data and was convinced that geometry and mathematics could be used to explain the number, distance, and motion of the planets.

9. J. Kepler believed that the Sun exerted a force on the planets.

10. J. Kepler discovered about 10 laws that describe the motion of every planet and satellite.

11. All comets can be divided into two groups: long-period comets and short-period comets.

12. Long-period comets have orbital periods longer than 300 years, and short-period comets have orbital periods shorter than 300 years.

13. It was N. Copernicus who found that the planets move faster when they are closer to the Sun and slower when they are farther away from the Sun.

14. J. Kepler also found that there is a mathematical relationship between periods of planets and their mean distances away from the Sun.

Ex.11. Translate into English paying special attention to the Rules of the Sequence of Tenses:

1. Школьник спросил учителя, использовал ли датский астроном Тихо Браге телескопы в своих исследованиях.

2. Уже в 18 веке ученые знали, что они могут использовать геометрию и математику для объяснения законов движения планет.

3. Он хотел знать, хранится ли химическая энергия в пище.

4. Студент не знал, что гласит первый закон Йохана Кеплера, великого немецкого физика и астронома.

5. В своих научных трудах Йохан Кеплер утверждал, что траектории планет представляют собой эллипсы.

6. Школьник спросил своего старшего брата, изучающего физику, вращается ли Солнце вокруг Земли. – Старший брат ответил, что нет, это Земля, как и другие планеты, вращаются вокруг Солнца.

7. Старшеклассник выступил с докладом, в котором он сказал, что существуют кометы с разным периодом обращения.

8. Лектор знал, что ученые хранят эталон килограмма недалеко от Парижа, в городке Севр.

9. Докладчик полагает, что длительность вращения по орбите указанной планеты слишком велик.

10. В своих трудах датский астроном Тихо Браге неоднократно сообщал, что он видел солнечное затмение в 1560 г.

11. Экзаменатор спросил студента, может ли тот описать движение Луны как спутника Земли на английском языке? Подумав немного, студент сделал короткое сообщение по данному вопросу на английском языке. Экзаменатор тотчас же поставил студенту оценку “отлично”.

12. Еще в школе Питер знал, что длина, масса и время – это три основные физические величины.

Ex.12. Read and translate the following text:

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