The Size and Shape of the Earth

The size and the shape of the earth were not always calculated accurately. Most ancient peoples thought the earth was flat, but there are many simple proofs that the earth is a sphere. For instance, as a ship approaches from over the horizon, masts or funnels are visible. As the ship comes closer, more of its lower parts come into view. Final proof, of course, was provided by circumnavigating the globe and by photographs taken from spacecraft.

The Greek geographer and astronomer Eratosthenes was probably the first (about 225 B.C.) to measure successfully the circumference of the earth. The basis for his calculations was the measurement of the elevation of the sun from two different points on the globe. Two simultaneous observations were made, one from Alexandria, Egypt (Point B), and the other from a site on the Nile near the present Aswan Dam (Point A). At the latter point, a good vertical sighting could be made, as the sun was known to shine directly down a well at noon on the longest day (June 23) of the year.

Eratosthenes reasoned that if the earth were round, the noonday sun could not appear in the same position in the sky as seen by two widely separated observers. He compared the angular displacement of the sun (Y) with the distance between the two ground sites, A and B.

E ratosthenes measured the distance (X) between Points A and В as 5.000 stadia (about 575 miles – 925.175000 klm.). Although the observer at Point A saw the sun directly overhead at noon, the observer at В found the sun was inclined at an angle of 7° 12' (Y) to the vertical. Since a reading of 7° 12' corresponds to one-fiftieth of a full circle (360°), Eratosthenes reasoned that the measured ground distance of 5.000 stadia must represent one-fiftieth of the earth’s circumference. He calculated the entire circumference to be about 28.750 miles (46.258750 klm.).

The following measurements are currently accepted:

Avg. diameter 7.918 mi. – 12.740062 klm.

Avg. radius 3.959 mi. – 6.370031 klm.

Avg. circumference 24.900 mi. – 40.064100 klm.

Exercise 7. Answer the following questions:

Questions:

1. Were the size and the shape of the earth calculated accurately in ancient times?

2. Most ancient people thought that the earth was round, didn’t they?

3. Are there any simple proofs that the earth is a sphere?

4. The photographs of the globe were taken from spacecraft, weren’t they?

5. Who was the first to measure successfully the circumference of the earth?

6. What was the basis of Eratosthenes’ calculations?

7. The distance between points A and B was 5.000 stadia, wasn’t it?

8. How long was the earth’s circumference according to Eratosthenes’ calculations?

Part 2. The Life on Earth

Study the list of vocabulary and pronounce the words after the teacher:

Vocabulary:

definite [’definit] – определённый

definition [‚defi’ni∫(ə)n] – определение

conception [kən’sep∫(ə)n] – понятие

sign [sain] – знак, признак

matter [’mætə] – материя

organic/inorganic – органический/неорганический

alive/dead – живой/мёртвый

creature [’kri:t∫ə] – существо

to identify [tə ai’dentifai] – определять, отличать

dialectic materialism [‚daiə’lektik mə’ti(ə)riəliz(ə)m] – диалектический материализм

quality [’kwɔliti] – качество

characteristic [‚kæriktə’ristik] – свойство

structure [’strлkt∫ə] – состав

substance [’sлbstəns] – вещество

correlation [‚kɔri’lei∫(ə)n] – соотношение

hydrogen [’haidridჳən] – водород

carbon [’ka:bən] – углерод

oxygen [’ɔksidჳən] – кислород

nitrogen [’naitridჳən] – азот

sulphur [’sлlfə] – сера

phosphorous [’fɔsfərəs] – фосфор

sodium [’səudjəm] – натрий

magnesium [mæg’ni:ziəm] – магний

chlorine [’klɔ:ri:n] – хлор

iron [aiən] – железо

calcium [’kælsiəm] – кальций

potassium [pə’tæsiəm] – калий

nuclein [’nju:kliin] – хим. нуклеин

acid [’æsid] – кислота

protein [’prəuti:n] – белок

carbohydrate [‚ka:bəu’haidr(e)it] – углевод

lipid [’lipid] – липид

c ell structure [‚sel ’strлkt∫ə] – клеточное строение

metabolism [mə’tæbəliz(ə)m] – обмен веществ, метаболизм

self-regulation [self ‚regju’lei∫(ə)n] – само-регуляция

mental functions [’mentl ’fлŋk∫(ə)nz] – психические функции

heredity [hi’rediti] – наследственность

changeability [‚t∫eindჳə’biliti] – изменчивость

reproduction [‚ri:prə’dлk∫(ə)n] – размножение

individual development [‚indi’vidჳuəl di’veləpmənt] – онтогенез/индивидуальное развитие

similarity [‚simi’læriti] – сходство

feeding [’fi:diŋ] – питание, корм

Exercise 1. Practice the reading of the following words and expressions and translate them into Russian:

dialectic materialism, mental functions, carbohydrate, organic matter, cell structure, hydrogen, alive creatures, inorganic substances, individual development, historical development, similarities and differences, chlorine, several characteristics, protein, potassium, matter movement, correlation, heredity, iron, identify the difference, sulphur, important elements, acid, oxygen

Exercise 2. Match the words on the left with their definitions on the right:

1. sign a. substance of which something is made

2. matter b. gaseous element essential to life and combustion

3. quality c. gesture, mark, or symbol conveying the meaning

4. structure d. any of complex organic compounds that are essential for life

5. oxygen e. degree or standard of excellence

6. protein f. complex construction

7. similarity g. organic substance that contains fat

8. heredity h. likeness, resemblance

9. lipid i. passing on of characteristics from one generation to another

Exercise 3. Match the beginnings of following sentences with their ends:

1. The word “life” doesn’t ... a. the same elements.

2. There are several signs that ... b. alive creatures.

3. All plants and animals are ... c. a possible definition for the word “life”.

4. “The Theory of Dialectic Materialism” gives ... d. have any special definition.

5. Both organic and inorganic substances have ... e. proteins, carbohydrates and fat.

6. All organic creatures contain nuclein acids, ... f. differ organic matter from inorganic.

Exercise 4. While reading the following text, find the synonyms to the words given below:

1. existence - 4. chronicle - 7. significant -

2. animate - 5. personal - 8. principal -

3. substantiality - 6. various - 9. motion -

Read the text “Life. What Is It?” and answer the following questions:

1. What is life according to the theory of Dialectic Materialism?

2. What is the difference between organic and inorganic substances?

3. Name three alive creatures mentioned in the text.

4. What are the main elements of organic and inorganic substances?

5. What characteristics do all organic substances have?