10_geography_1st Seasons_and_Time.pptx

its 10th class geography 1st chapter seasons and time

1. Seasons and Time MUHAMMED HISHAM NK [email protected]

2. Reasons for different seasons The Earth's revolution The tilt of the axis The parallelism of the Earth's axis. Apparent movement of sun

3. 66 1 ⁄ 2 ° from the orbital plane 66 1 / 2 °

4. APPARENT MOVEMENT OF THE SUN The position of the Sun in relation to the Earth varies apparently between Tropic of Cancer (231⁄2° North) and Tropic of Capricorn (231⁄2° South). This is known as the apparent movement of the Sun.

5. EQUINOXES The apparent position of the Sun will be over the Equator on March 21 and September 23 Equal amount of sunlight is received in the Northern Hemisphere as well as in the Southern Hemisphere length of day and night will be equal on both hemispheres

6. EQUINOXES MARCH 21 TROPIC OF CANCER TROPIC OF CAPRICORN EQUATOR

7. Summer Solstice From 21 March onwards, the Sun apparently shifts from the Equator northwards and reaches vertically over the Tropic of Cancer (231⁄2°N) on 21 June . On this day the Northern Hemisphere experiences its longest day and shortest night.

8. TROPIC OF CANCER SUMMER SOLSTICE TROPIC OF CAPRICORN EQUATOR JUNE 21

9. TROPIC OF CANCER TROPIC OF CAPRICORN MARCH 21 JUNE 21 SEPTEMBER 23 DECEMBER ‍ 22 EQUATOR 23 1 / 2 N 23 1 / 2 S SPRING

10. SPRING SEASON Northern Hemisphere generally experiences spring season between 21 March and 21 June. Spring is the season of transition from winter to summer. The peculiarities of spring season- plants sprouting, mango trees blooming and jackfruit trees bearing buds.

11. TROPIC OF CANCER TROPIC OF CAPRICORN MARCH 21 JUNE 21 SEPTEMBER 23 DECEMBER ‍ 22 EQUATOR 23 1 / 2 N 23 1 / 2 S SPRING SUMMER

12. Summer season The southward apparent movement of the Sun begins from 21 June and again reaches vertically above the Equator on 23 September.

13. EQUINOXES TROPIC OF CANCER TROPIC OF CAPRICORN EQUATOR SEPTEMBER 23

14. Winter Solstice From 23 September, the Sun apparently shifts from the Equator and reaches vertically over the Tropic of Capricorn (23 1⁄2 °S) on 22 December. Northern Hemisphere experiences its shortest day and longest night.

15. WINTER SOLSTICE TROPIC OF CANCER TROPIC OF CAPRICORN EQUATOR DECEMBER 22

16. TROPIC OF CANCER TROPIC OF CAPRICORN MARCH 21 JUNE 21 SEPTEMBER 23 DECEMBER ‍ 22 EQUATOR 23 1 / 2 N 23 1 / 2 S SPRING SUMMER AUTUMN

17. Autumn Transition from the severity of summer towards winter. The atmospheric temperature decreases considerably. There is shortening of day and lengthening of night. The trees generally shed their leaves - The shedding of leaves is a form of adaptation to survive the forthcoming dry winter.

18. TROPIC OF CANCER TROPIC OF CAPRICORN MARCH 21 JUNE 21 SEPTEMBER 23 DECEMBER ‍ 22 EQUATOR 23 1 / 2 N 23 1 / 2 S SPRING SUMMER AUTUMN WINTER

19. W inter Season Winter Season

20. Rotation and calculation of time

21. Greenwich time (GMT) and time zones The zero degree longitude is known as the Greenwich Meridian. It acquires its name from Greenwich, the place where the Royal British Observatory is situated and through which this line passes. Time is calculated worldwide based on the Greenwich Line. Hence this line is also known as the prime meridian.

22. Greenwich time (GMT) and time zones The local time at the prime meridian is known as the Greenwich Mean Time. Based on the Greenwich Merdian, the world is divided into 24 zones, each with a time difference of one hour. These are known as time zones.

23. Standard time Each country in the world considers the longitude that passes almost through its middle as the standard meridian. The local time at the standard meridian is the standard time of that country.

24. Indian Standard Time (IST) The longitudinal extent of India is from 68°E to 97°E. The 821⁄2°E longitude which passes almost through the middle of these longitudes has been fixed as the standard meridian of India.

25. International Date Line 180° longitude to the east and west of Greenwich The places situated East and West of this line will be having two different days It doesn’t pass through the corresponding land areas. The line is in such a way that it passes through Bering - strait in Pacific Ocean and avoid some of the inhabited islands The travellers who cross this line from the West calculate he time by advancing it by one day and those who cross the line from the west deduct one day.

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