MEASURING TIME ON THE EARTH

Date: 2015-10-07; view: 358.

People can determine the approximate time of day by determining where the Sun is in the sky. If the Sun is near an imaginary line drawn from due north to due south, it is about 12:00 noon. Humans have used movements of the Earth, the Moon, and the Sun to measure time for thousands of years. Around 3000 B.C., the Babylonians devised a method of timekeeping using their counting methods and they based this method on the number 60. They noticed that the Sun appeared to take a circular path through the sky. Because they based their counting methods namely on the number 60, they divided a circle into 360 parts called degrees. The symbol for degree є was their symbol for the Sun.

The Earth spins and makes one complete turn in about 24 hours.This spinning causes the Sun to appear to move across the sky from east to west. It takes 24 hours from when the Sun is the highest in the sky (noon) until it is the highest in the sky again (noon the next day). If the Earth spins approximately 360° in 24 hours, then it spins through 15° in one hour. This led to the setting up of time zones on the Earth that have the same time in minutes but vary in hours. A time zoneis an area 15° wide in which the time is the same. Ideally, time zones should be equal in size and follow lines drawn from the North Pole to the South Pole. However, for convenience, one must modify time zones to fit around city, state, and country borders, and other key sites.

You can see that a problem would quickly arise if you just kept dropping back an hour earlier for each 15°. Eventually, you would come around the Earth and it would be 24 hours earlier. It cannot be two different days at the same spot, so one must add a day to the time at the International Date Line. If it is Monday to the east of the date line, then it is the same hour on Tuesday to the west of the date line. This line passes through the Pacific Ocean (around islands, such as New Zealand) directly opposite the Prime Meridian, the starting point for this worldwide system of measuring time. The Prime Meridian is an imaginary line drawn on the Earth that passes through Greenwich, England. Time based on this method is the so called “Coordinated Universal Time (UTC)”. In some areas, you must modify this time in summer so that there are more hours of daylight in the evening. People refer to this time as Daylight Saving Time (DST). Some areas apply local modifications to this system as well. If you look at the globe, you will see that there're 24 time zones on the globe. Lines of longitude roughly determine the locations of time zone boundaries. Notice that each successive time zone to the west is one hour earlier.

13. Find in the text equivalents for the following Russian words and word combinations:

определить приблизительное время; точно с севера на юг; измерять время; жители Вавилона; изобрести (придумать, разработать) метод слежения за временем (подсчета времени); способы счета; заметить что-либо; градус; символ для; с Запада на Восток; совершать круговые вращения; пройти по небу приблизительно 15 °; привести к чему-либо (стать причиной для чего-л.); установить (создать) временные зоны; Северный Полюс; Южный Полюс; прочертить (провести) линии; видоизменять, модифицировать; границы страны; ключевая (основная) точка местоположения; возникнуть (о проблеме); в одном и том же месте; нулевой (главный) меридиан; точка отсчета (отправная точка); всемирный (распространенный во все мире); система измерения времени; переход на «летнее время»; всемирное координированное время; воображаемая линия; проходить через (о линии, меридиане); земной шар (глобус); поделить земной шар на часовые пояса.

14. Answer the following questions:

a) What is the way of determining the approximate time of the day?

b) Humans have used movements of the Earth, the Moon, and the Sun to measure time for millions f years, haven't they?

c) When did the Babylonians devise a method of timekeeping using their counting methods?

d) Did the Babylonians base their counting methods on 60 or 120?

e) What did the Babylonians notice concerning the Sun?

f) How many degrees did the Babylonians divide a circle into?

g) How long does it take from when the Sun is the highest in the sky (noon) until it is the highest in the sky again (noon the next day)?

h) What did the symbol є mean for the Babylonians?

i) What led to the setting up of time zones on the Earth?

j) Must one add a day or two days to the time at the International Date Line?

k) How many time zones are there on the globe?

l) How wide is an area of a time zone?

m) What do lines of longitude roughly determine?

n) What is the so called “Coordinated Universal Time”?