We are working with the map. Determination of standard time at a given point
1. On the map, determine how many time zones cross the territory of North America.
2. Using the map, determine standard time in the indicated cities, if it is noon (12.00) in London at that time.
Dakar 12:00
Kinshasa 13:00
Wellington 1:00
Paris 13:00
Santiago 9:00
London 12:00
Tokyo 21:00
New York 7:00
Los Angeles 5:00
Canberra 23:00
Beijing 20:00
3. Set the order in which they will meet the New Year
residents of these cities.
7 - San Francisco
5 - Helsinki
4 - Tehran
3 - Irkutsk
1 - Wellington
4. Write in the table the names of the cities in accordance with the time of the year, which will be in them on January 15th.
Cities: Buenos Aires, Canberra, New Delhi, Mexico City, Yakutsk, Beijing, Brasilia, Dakar.
SEASONS IN SOME CITIES IN THE WORLD IN JANUARY
5. On contour map hemispheres circle the lines of the tropics and polar circles in different colors. Write down the latitude values for each.
66.5 N, 23 N, 23.5 S, 66.5 S
6. Determine on which fragments of the maps are shown:
1) Antarctic Circle
2) Northern Tropic
3) Meridian 180
4) Southern Tropic
7. Using physical map Russia, explain why in the summer
there are white nights in St. Petersburg, but not in Moscow.
In summer, the sun sets below the horizon, but due to the tilt of the Earth, the rays of light continue to illuminate the Earth tangentially. Beyond the Arctic Circle, the Polar Day is established, because. St. Petersburg is closer to the Arctic Circle, it has white nights.
Give 5 examples of Russian cities where this phenomenon is observed.
Murmansk, Norilsk, Vorkuta, Naryan-Mar, Salekhard.
In what other countries can it be observed?
Finland, Iceland, Sweden, Norway, Canada, Denmark, UK, Estonia, USA.
8. Specify the sequence of twilight in cities:
in December:
Washington - 3
Santa Fe de Bogotá - 1
The time zone map is designed to determine in which time zones the given points are located. For the entire globe, it is given in the Aviation Astronomical Yearbook. The same map shows the continents, states and big cities, time zone boundaries and their numbers. For the territory of the USSR, a map of time zones is shown in Fig. 3.10. To determine what time zone you are in
Rice. 3.10. Map of time zones of the USSR
one or another point, it is necessary to find a given point on the map of time zones by its name and see in which time zone it is located. If a given point on the map is not indicated, then its position is plotted on the map according to the latitude and longitude indicated on the map frame, after which it is determined in which time zone it is located.
Determination of standard time at a given point.
The standard time system makes it easy to determine the standard time at any point. There is a certain relationship between standard time and time zones. The difference between the standard times of two points is equal to the difference between the numbers of the time zones, i.e.
where - numbers of time zones; - standard time in these time zones. This ratio allows you to determine the standard time at a given point according to the known standard time of another point.
Standard time at a given point is determined by the formula
where is the difference between the numbers of the time zones of these points.
The indicated difference is added to the known standard time if the point whose time is being determined is located to the east of the point whose time is known, and if to the west it is subtracted.
Example. In Arkhangelsk, standard time. Determine standard time in this moment in Yakutsk.
The local time. The earth makes a full rotation around its axis (360°) in a day (24 hours). In different places on the globe, located on different meridians, that is, having different longitudes, at the same moment, the clock shows different time days.
For example, when it is 4 pm in Moscow, 6 pm in Yekaterinburg, 10 pm in Yakutsk, and midnight in Petropavlovsk-Kamchatsky. But on the same meridian at each point from the North Pole to the South, the time of day is the same. This time is called local time.
Rice. 9. Time zones of the world and Russia
But it is inconvenient to use local time, it interferes with the implementation of communications between different countries and between parts of our vast extent from the west to the east of the country. Therefore, astronomers have developed a system of so-called standard time. By the decision of the International Astronomical Congress in 1884, the entire Earth was divided along the meridians into 24 zones, each of them included 15 ° longitude (Fig. 9), since the Earth rotates 15 ° in one hour. Thus, the time in each zone differs from the time in neighboring zones by 1 hour. The Earth rotates from west to east, so in the belt immediately adjacent to this one from the east, the time of day will be 1 hour more, and from the west - 1 hour less.
The time zone is taken as zero, in the middle of which the meridian of the Greenwich Observatory (Great Britain) passes. The same belt serves as the 24th. From the zero zone, time zones are counted (Fig. 10), following from west to east.
How much and in what direction should the clock be moved if we move from the 2nd time zone to the 8th; in the 1st?
The beginning of a new day is conventionally considered the 12th time zone. Meridian 180 passes through its middle, which is considered date line and also indicating the transition from the Eastern to the Western hemisphere, and vice versa. Crossing this conditional line, we get from one day to another. For example, the crew of an airplane headed by Valery Chkalov flew to America from our country on June 18, 1937, flew without landing for two days, but landed in America not on June 20, but on June 19, that is, as if returned to yesterday. For the same reason, the first travelers around the world - the satellites of Magellan - "lost" one day, although they carefully kept a ship's diary.
What changes in time will occur when crossing the date line from west to east; from east to west?
Rice. 10. How time zones are counted
There are 12 time zones in our country. The capital of Russia - Moscow is located in the second time zone, and the Chukotka Peninsula - in the twelfth. However, for convenience, some time zones have been merged. That is why the onset of the New Year within Russia can be met not eleven, but only nine times. Interestingly, most Russians (60.5%) live according to Moscow time. There are 16 constituent entities of the Russian Federation in the second time zone, another 35 regions have specially changed the time in order to live “in step” with the capital. It is not difficult to calculate the standard time of each point if you know the number of the time zone in which this point is located. Therefore, if we know that in Moscow (the second time zone) it is 10 am, then in Berlin (the first time zone) it is 9 am, and in Tbilisi (the third time zone) it is 11 am.
And yet, the boundaries of time zones (see Fig. 9) do not pass strictly along the meridians, which is also done for convenience, taking into account the administrative division of the country, so that one or another administrative unit - region, republic, their capital - is in the same time zone . The standard time of some time zones has been given special names. For example, the time of the zero zone is called Western European, the first - Central European, the second - Eastern European.
But that's not all. In 1930, standard time in our country was moved forward one hour by a resolution (decree) of the Council of People's Commissars in order to make fuller use of daylight during the working day and save electricity. This time is called maternity leave. All transport and all means of communication in our country work according to Moscow standard time for the convenience of counting time and avoiding confusion due to the large number of time zones. You can hear about different time on the territory of our country every day on the radio.
Determine on the map of time zones in which time zone your region, republic, city is located.
Since 1981, in our country, as in a number of other countries, summer time has also been introduced. Every year on the last Sunday of March, the clock is moved one hour ahead of standard and standard time. And daylight saving time is canceled on the last Sunday of September by moving the hour hand back one hour. Thus, from the end of March to the end of September in our country, two hours are added to the standard time of any point, and in the autumn-winter period - one hour.
Questions and tasks
- What is local time?
- Why is standard time introduced?
- In what time zones is our country located? How many time zones separate Chukotka and the Kaliningrad region?
- Where is the date line?
- What is daylight savings time? summer time? For what purpose are they introduced?
- Make up a problem to determine the standard time and solve it.
- How will the received standard time value change for any of the points of our country in winter time; in summer time?
- Why is it necessary to change the clock when flying from Moscow to Yekaterinburg, but when flying to Murmansk almost the same distance is not necessary?
