Short Questions: Motions of the Earth | NCERT Summary: UPSC PDF Download

Q1: Distinguish between rotation and revolution.
Ans: Rotation: Rotation refers to the movement of an object around its own axis, like when you spin a top or turn a wheel. Think of it as something turning or spinning in place. For example, when the Earth spins on its axis, it causes day and night. Imagine you're standing in one spot and twirling around - that's you rotating.
Revolution: Revolution, on the other hand, is when an object moves around another object in a circular path. A good example is the Earth moving around the Sun. It takes about 365 days for the Earth to complete one revolution around the Sun. So, when you think of revolution, think of something going around in a big circle.

Q2: How are days and nights formed?
Ans: The earth receives light from the Sun. Because of its spherical shape; only half of it gets light from the Sun at a time. The portion facing the Sun experiences daytime while the other portion away from the Sun experiences night.

Q3: What will happen if the earth stops rotating?
Ans: Life on the planet will be impossible if the earth stops revolving.

Q4: Why the earth faces nights and day?
Ans: The rays of the Sun fall at different times on the planet due to the rotation of the earth, resulting in day and night.

Q5: In the Northern hemisphere, which day is considered as the shortest day?
Ans: The shortest day in the Northern Hemisphere is December 22nd.

Q6: When do the longest day and the shortest night take place?
Ans: The Northern Hemisphere is tilted towards the Sun on June 21st, and hence the Sun's rays fall directly on the Tropic of Cancer. This raises the temperature in that area. Because the sun shines on a large chunk of the northern hemisphere, it is summer in those areas. On June 21, the longest day and the shortest night occur.

Q7: Define the motion of the earth.
Ans: Rotation is the earth's daily motion. There are two types of motion on Earth: rotation and revolution. The motion of the earth on its axis is known as rotation. The world rotates once every 24 hours, which is why the days and nights, as well as the seasons, change.

Q8: What is rotation?
Ans: Rotation is the movement of the earth on its axis. The rotation of the Earth on its axis takes 24 hours.

Q9: What is the reason for the season change?
Ans: As the earth circles around the Sun, its location varies over time, resulting in the change of seasons.

Q10: What is a leap year? Why does it take place?
Ans: On average, the Earth travels around the Sun in 365 14 days. One year is defined as 365 days. The remaining 6 hours, multiplied by 4, equals 24 hours, or one day. The month of February has an extra 29th day, and the year has 366 days, making it a leap year.

Q11: When do the days get shorter and why?
Ans: During the winter, the days are shorter. The evenings are longer than the days throughout the winter season. The days are longer than the nights throughout the summer.

Q12: How does the change of the season take place?
Ans: The revolution is what causes the seasons to cycle. The shift in the earth's location around the Sun causes the seasons. The earth follows its own orbit or course around the Sun. The four seasons, summer, winter, autumn, and spring are caused by the earth's movement and its axis tilt in a set direction.