Motions of the Earth: Rotation, Revolution, and Leap Year Explained for Class 6
FAQs on NCERT Solutions for Class 6 Social Science Chapter 3 The Earth Our Habitat - 2025-26
1. What are the two types of motions of the Earth as explained in NCERT Class 6 Social Science Chapter 3?
The NCERT solutions for Class 6 Social Science Chapter 3 explain two primary motions of the Earth:
- Rotation: This is the movement of the Earth on its axis, which causes day and night. The Earth takes about 24 hours to complete one rotation.
- Revolution: This is the movement of the Earth around the Sun in a fixed path or orbit. It takes 365¼ days to complete one revolution, which leads to the change in seasons.
2. How do the NCERT Solutions for Class 6 Geography explain the concept of a leap year?
The NCERT solutions explain that the Earth takes 365¼ days (or 365 days and 6 hours) to revolve around the Sun. For convenience, a normal year is counted as 365 days, and the extra 6 hours are saved. Over four years, these saved hours add up to 24 hours (or one full day). This extra day is added to the month of February every fourth year, making it 29 days long. Such a year with 366 days is called a leap year, as per the 2025-26 CBSE syllabus.
3. What is the 'circle of illumination' according to the Class 6 NCERT textbook?
In the context of the NCERT solutions, the circle of illumination is the imaginary line that separates the part of the Earth experiencing daylight from the part experiencing darkness (night). Since the Earth is a sphere, only half of it gets light from the Sun at a time. This circle is not fixed and continuously moves as the Earth rotates on its axis.
4. What is the correct way to differentiate between the Summer and Winter Solstice as per the CBSE pattern for Class 6?
As per the CBSE pattern for Class 6, the correct method to differentiate is by focusing on the tilt of the hemisphere relative to the Sun:
- Summer Solstice: This occurs around June 21st when the Northern Hemisphere is tilted towards the Sun. This results in the longest day and shortest night of the year in the Northern Hemisphere.
- Winter Solstice: This occurs around December 22nd when the Northern Hemisphere is tilted away from the Sun. This leads to the shortest day and longest night of the year in the Northern Hemisphere.
5. How do the NCERT solutions for Chapter 3 explain why seasons change?
The NCERT solutions explain that seasons change primarily due to two combined factors: the Earth's revolution around the Sun and the consistent tilt of its axis. Because the axis is tilted, different parts of the Earth receive more direct sunlight at different times during the year-long orbit, which causes the cycle of summer, winter, autumn, and spring.
6. If the Earth's axis were not tilted, how would this affect the seasons and the length of days?
If the Earth's axis were not tilted, the Sun's rays would fall directly on the equator all year round. The circle of illumination would consistently pass through both poles. As a result, every location on Earth would experience equal days and equal nights throughout the year. Most importantly, there would be no distinct seasons, as the amount of solar energy received by any given region would remain constant.
7. Why does the Southern Hemisphere experience winter when the Northern Hemisphere has summer?
This phenomenon is a direct result of the Earth's constant axial tilt. Around June, when the Northern Hemisphere is tilted towards the Sun, it receives more direct and concentrated solar energy, causing summer. At this same time, the Southern Hemisphere is tilted away from the Sun, receiving slanted and less intense sunlight, which leads to it experiencing winter. The positions are reversed during December.
8. How does understanding the concept of an 'equinox' help in solving NCERT questions correctly?
Understanding the concept of an equinox is crucial for solving NCERT questions about the equality of day and night. An equinox happens twice a year (around March 21st and September 23rd) when neither of the Earth's poles is tilted towards the Sun. On these specific days, the Sun's rays shine directly on the equator, causing the entire Earth to experience equal lengths of day and night. This knowledge is key to correctly answering why and when this equality occurs.
