NCERT 6th Class (CBSE) Social Science: Rotation and Revolution

Question: Explain the effect of the tilt of the earth’s axis?

Answer: The tilt of earth’s axis causes the change in seasons when the north pole is tilted toward the sun, The sun rays are falling directly. The northern hemisphere has the summer solstice and when the south pole is tilted towards the sun, the rays of the sun, falling on the tropic of Capricorn and the southern hemisphere has the summer season.

Question: What is the difference between Autumnal and Vernal equinox?

Answer: Autumnal:

1. The overhead rays are in transition from the northern to southern hemisphere.
2. It occurs on 23rd September.
3. This position is between June 21st and the December 22 for three months after summer solstice.
4. We experience Autumn season.

Vernal:

1. The overhead rays are transitions from the southern to northern hemisphere.
2. It occurs on 21 March.
3. The position is between December 22 and June 21 for three months after the winter solstice
4. We experience spring seasons.

Question: What is the importance of inclination of the earth’s axis?

The length of days and nights is not the same throughout the year. This variation is due to the inclination of the earth’s axis. Due to this inclination, the Northern hemisphere remains inclined towards the sun for half of the year and the southern hemisphere on the other half of the year.

Question: Why are days longer than nights during the summer season?

Answer: The days are longer than nights because the North Pole is inclined towards the sun the south pole is turned away from the sun. This results longer days and shorter nights.

Question: Why do we have a leap year?

Answer: The earth takes 365 days 5 hours 48 minutes and 56 seconds to complete on revolution around the sun. But, for our convenience we count only 365 days in a year the balance is about 6 hours is computed to one extra day after every four years.

Question: What are the factors responsible for the change of seasons?

Answer: The change of seasons is due to:

1. The rotation of the earth on its axis.
2. The revolution of the earth on its axis.
3. The inclination of the earths axis.

Question: What are the effects of the earths rotation?

Answer: The effects of the earth’s rotation are:

1. It makes us fell that the sun, moon and the other heavenly bodies move from east to west.
2. It causes bulging of the earth and flattening poles.
3. It is causes days and nights on the earth.
4. It is gives us the concept of direction based on sunrise and sunset.
5. It causes deflection in the direction of winds and ocean currents.
6. It gives us a day of 24 hours.
7. It causes tides twice a day.