Movements of the earth.

Rotation and Revolution

1. Social Studies Unit-01 Studying the Earth

2. 2. Movements of the Earth

3. ROTATION:

4. The Earth rotates on it’s own axis. It’s axis is an imaginary line that passes through the North poles and the South poles. This axis is tilted at an angle of 23.5

5. The Earth takes 24 hours to complete one rotation about its axis. This is called One Earth-day The Earth travels 2,200 km per hours.

6. The Effect of the Rotation of the Earth:

7. The Rotate of the Earth causes Day and Night . As the Earth rotates on its axis, half of the earth faces the sun and half of the earth faces away from the sun. The half of the Earth that faces the sun will experience Day . While the half of the Earth that faces away from the sun will experience Night .

8. Image of day and night:

9. The period between Night and Day is called Dawn . The period between Day and Night is called Dusk .

10. REVOLUTION

11. The Earth revolves around the Sun is called Revolution . The Earth revolves around the sun in fixed path and it is called orbit . The Earth’s orbit is Elliptical or Oval shape. The Earth takes 365 days and 6 hours to complete one revolution. The speed of Earth’s revolution is about 18 miles per hour.

12. Interesting fact: The Earth, takes 365 days and 6 hours , to complete one revolution. The extra 6 hours accumulate over four years and are added as a day to the month of February every fourth year. So February, which usually has 28 days , has 29 days every fourth year. This year is called a “ Leap Year ” and has 366 days .

13. The Effects of the Revolution of the Earth:

14. Most places on Earth experiences different seasons in a year. THREE FAC TORS CAUSES THE SEASON: The revolution of the Earth around the Sun . The tilt of the Earth’s axis of Rotation . The tilt’s of the Earth axis remain constant .

15. The Earth experience different seasons in a year, namely Summer, Winter, Spring, Autumn.

16. In March ,neither of the poles is facing the sun. It is the Spring in the Northern Hemisphere, and Autumn in the Southern Hemisphere. In June, the North pole is facing the Sun, While the south pole is facing away from it. So it is Summer in the Northern Hemisphere, and Winter in the Southern Hemisphere. In September, neither of the poles is facing the Sun. It is Spring in the Southern Hemisphere and Autumn in the Northern Hemisphere. In December, the South pole is facing the Sun, While the North pole is facing away from it. So it is Summer in the southern Hemisphere and Winter in the Northern Hemisphere.

17. The part of the Earth that is tilted towards the sun gets the directs rays of the Sun and has Summer , While the part that faces away from the Sun, receives less heat from the Sun, and so, has Winter . Twice a year, in March and September, neither of the poles is facing the Sun, and all parts of the Earth get roughly equal hours of daylight and darkness .

18. At this time, Places on Earth have seasons like Autumn and Spring , Which are neither too hot nor too cold . The Northern Hemisphere and the Southern Hemisphere experiences opposite seasons . FOR EXAMPLE: In December, Canada , which lies in the Northern Hemisphere, has Winter . While Australia in the Southern Hemisphere has Summer . In June, Canada experience Summer , while Australia experience Winter .

19. Summer season: The Summer months are hot and dry . The days are long and nights are short . In many places river and lakes run dry.

20. Autumn season: In Autumn, leaves change colour and start falling from the tees . Days and Nights are of the same length . The weather is Pleasant .

21. Winter season: It is very cold during Winter. In many places Snow falls . Trees lose all their leaves. The Days are short and the Nights are long .

22. Spring season: During spring, Trees Sprout new leaves and Flowers bloom after the cold winter months. Birds build nests . The Weather is mild and pleasant .

23. MONTH NORTHERN HEMISPHERE SOUTHERN HEMISPHERE MARCH SPRING AUTUMN JUNE SUMMER WINTER SEPTEMBER AUTUMN SPRING DECEMBER WINTER SUMMER

24. IN INDIA: In India, we have yet another season- the MONSOON . This is the season of rains in India. It occurs every year between June and August .