NCERT Class 6 - Social Science - Geography
Chapter 3 - MOTIONS OF THE EARTH
Table of Contents
⬇️ ⬇️ ⬇️ ⬇️ ⬇️
Motions Of The Earth
- The earth has two types of motions, namely rotation, and revolution.
- Rotation is the movement of the Earth on its axis.
- The axis of the earth which is an imaginary line, makes an angle of 66½° with its orbital plane.
- The circle that divides the day from night on the globe is called the circle of illumination.
- Revolution is the movement of the Earth around the sun in a fixed path or orbit. It takes 365¼ days to revolve around the sun.
- The Earth is going around the sun in an elliptical orbit.
- Seasons (summer, winter, spring, and autumn) occur due to the change in the position of the earth around the sun.
Summer Solstice
- On 21st June, The rays of the sun fall directly on the Tropic of Cancer (Northern Hemisphere). As a result, these areas receive more heat (Summer Season).
- The longest day and the shortest night at these places occur on 21st June.
- This position of the earth is called the "Summer Solstice." i.e. the summer solstice is the day with the longest period of daylight and shortest night of the year.
- Summer Solstice occurs when one of Earth's poles has its maximum tilt toward the Sun.
- At this time the Southern Hemisphere has a winter season. The nights are longer than the days.
- The summer solstice occurs during the summer season, usually on the 21st of June in the Northern Hemisphere and the 22nd of December in the Southern Hemisphere.
Winter Solstice
- On 22nd December, the Tropic of Capricorn (Southern Hemisphere) receives direct rays of the sun.
- It results in longer days and shorter nights i.e. summer season in the Southern Hemisphere.
- At this time the North Hemisphere has a winter season. The nights are longer than the days.
- This position of the earth is called the "Winter Solstice." i.e. the winter solstice is the day with the shortest period of daylight and longest night of the year.
- The winter solstice occurs during the winter season, usually on the 21st of June in the Southern Hemisphere and the 22nd of December in the Northern Hemisphere.
Quinox
- On 21st March and September 23rd, direct rays of the sun fall on the equator.
- So, at this position, the whole earth experiences equal days and equal nights. This is called an "Quinox."
- On 21st of March, is the spring season in the Northern Hemisphere. and autumn season in the Southern Hemisphere.
- On 23rd of September, is the autumn season in the Northern Hemisphere. and spring season in the Southern Hemisphere.
