1. What is the “equatorial bulge”?

2. Are all three models only approximations?

Task 2. Summarize the information about the different ways of describing the earth’s shape (in writing).

Revision

Ex. 1. Fill in the text with the appropriate word from the box.

ice age, took place, inhabitants, era, dates, human, cooled, liquid, primitive, rain, organisms, hemisphere, stages, forms, animal, earth’s, oxygen, species, evolved, crust, appeared, spread, dry, complex, moved, existence

History of the Earth

Although it is difficult to say anything definite about events that (1) _____ (2) _____ so long ago, scientists have been able to suggest some (3) _____ from the main (3) _____ in the history of our planet. 5,000 million years ago, they tell us, the earth came into (4) _____ as a mass of (5) _____ fire. About a thousand million years later the crust (6) _____ and hardened and seas were formed by (7) _____ . After about another thousand million years bacterialike cells (8) _____ in the seas. One of the earliest life forms to develop, about 2,000 million years ago, was algae, and they produced (8) _____ . Now that there was oxygen in the atmosphere, conditions were suitable for the development of more (9) _____ life forms. At first single-cell, and later, multicellular, (10) _____ appeared.

Meanwhile the (11) _____ of the earth was continually contracting and shifting and between 600 and 225 million years ago (12) _____ land gradually emerged. Some living forms then (13) _____ to the land and in time amphibians, insects and reptiles evolved.

At the same time forests and ferns (14) _____ over the land. Living (15) _____ then proceeded to flourish and multiply and many new (16) _____ evolved. About 223 million years ago flowering plants first (17) _____ on earth. This (18) _____ life for millions of years. Some 75 million years later the first mammals and birdlike creatures evolved.

About the next stage in the earth’s history more is known, thanks to the abundance of fossils from this biological clan to which (19) _____ beings belong, have been the dominant form of animal life. The first (20) _____ ape appeared about 40 million years ago and was followed by a manlike ape around 10 million years later. About a million years ago the (21) _____ landscapes were changed by the movements of snow and ice over the Northern (22) _____ . This period is known as the (23) _____ (24) ____ when the climate became warmer again about half a million years ago, the first human beings appeared. Humans are thus among the most recently arrived (25) _____ of the earth.

Ex. 2. Translate the text into Russian (in writing).

Latitude and Longitude

Locations on the earth's surface are specified in terms of the earth's axis of rotation. A great circle is any circle on the earth's surface whose center is the earth's center. The equator is a great circle midway between the North and South Poles. A meridian is a great circle that passes through both poles, and it forms a right angle with the equator. The prime meridian passes through Greenwich, England. The longitude of a point on the earth's surface is the angular distance between a meridian through this point and the prime meridian; the prime meridian is assigned the longitude 0°, and longitudes are given in degrees east or west of the prime meridian. Thus a longitude of 60°W identifies a meridian 60° west of the prime meridian.

The latitude of a point on the earth's surface is the angle between a line from the earth's center to it and another line drawn from the center to a point on the equator on the same meridian. Thus the latitude of the North Pole is 90°N, that of the South Pole is 90°S, and that of the equator itself is just 0°. A latitude of 60°N identifies a circle 60° north of the equator. Degrees of latitude and longitude are further divided into minutes [1° = 60 minutes (60')], and minutes are further divided into seconds [1' = 60 seconds (60')]. A nautical mile is equal to a minute of latitude, and is 6,080 ft in length. (A statute mile, used on land, is 5,280 ft in length.) Because of the way they are defined, parallels of latitude are equally spaced everywhere (hence the usefulness of the nautical mile), but meridians of longitude converge at the poles.

On December 22, the shortest day of the year in the Northern Hemisphere, the 23.5° tilt of the earth's axis means that no sunlight reaches any point within 23.5° from the North Pole. The Arctic Circle is the boundary of this region of darkness. On the same day, which is the longest day of the year in the Southern Hemisphere, there are 24 h of daylight at all points within 23.5° of the South Pole, and the Antarctic Circle is the boundary of this region of daylight. On June 22 the situations in the two hemispheres are reversed.

The Tropic of Cancer is the most northerly latitude in the Northern Hemisphere at which the sun is ever directly overhead at noon. The Tropic of Capricorn is corresponding latitude in the Southern Hemisphere. On June 22, when the North Pole is titled closest to the Sun and which is hence the day of maximum sunlight in the Northern Hemisphere, the noon sun is directly overhead 23.5 º north of the equator; hence the latitude of the Tropic of Cancer is 23.5º N. Similarly the latitude of the Tropic of Capricorn is 23.5 º S; the South Pole is tilted closest to the sun on December 22, when the noon sun is directly overhead at this latitude.

Ex. 3. Find the terms in the text which describe the following:

1. The name of the meridian which passes through Greenwich.

2. A great circle that is drawn midway between the North Pole and the South Pole.

3. The name of the most southerly latitude above which the sun is directly overhead at 12 noon.

4. The name of that latitude’s equivalent in the Northern Hemisphere.

5. The point that has a latitude of 90⁰ N.

6. The point that has a latitude of 90⁰ S.

7. A mile that is used on land.

8. Any circle on the earth’s surface whose centre is the earth’s centre.

Ex. 4. These words can all be explained in simpler, more everyday language. Can you do that?

1. location

2. rotation

3. assign

4. further

Ex. 5. Imagine you do not understand the following terms. Ask each other for an explanation.

1. Tropic of Cancer

2. Tropic of Capricorn

3. South Pole

4. North Pole

5. Equator

Ex.6. Translate the text into English using the vocabulary of the Unit.

Наша планета Земля шарообразна. Сейчас это известно каждому. Но прошло немало тысячелетий, потребовалось много усилий, пока человечество уверилось в том, что Земля – шар. Представление о том, что Земля – шар, появилось еще в VI в. до н. э. Край тени Земли при любом затмении Луны имеет округлую форму. Следовательно, форма Земли шарообразна. Определение размеров Земли – очень трудная задача. Земля велика. Воображаемая линия, вокруг которой происходит суточное вращение, называется земной осью. Точки, где земная ось пересекает поверхность Земного шара, называются географическими полюсами Земли.

it took much effort the idea edge eclipse rounded