# NCERT Class 6 Social Science Chapter 15 Motions of the Earth

NCERT Class 6 Social Science Chapter 15 Motions of the Earth Solutions to each chapter is provided in the list so that you can easily browse through different chapters NCERT Class 6 Social Science Chapter 15 Motions of the Earth and select need one. NCERT Class 6 Social Science Chapter 15 Motions of the Earth Question Answers Download PDF. NCERT SST Class 6 Solutions.

## NCERT Class 6 Social Science Chapter 15 Motions of the Earth

Also, you can read the NCERT book online in these sections Solutions by Expert Teachers as per Central Board of Secondary Education (CBSE) Book guidelines. CBSE Class 6 Social Science Solutions are part of All Subject Solutions. Here we have given NCERT Class 6 Social Science Chapter 15 Motions of the Earth, NCERT Class 6 Social Science Textbook of Our Pasts – I: History, The Earth – Our Habitat: Geography, Social and political Life: Civics. for All Chapters, You can practice these here.

### Motions of the Earth

Chapter: 15

THE EARTH – OUR HABITAT [GEOGRAPHY]

Q. 1. Answer the following questions briefly:

(a) What is the angle of inclination of the earth’s axis with its orbital plane?

Ans. The angle of inclination of the earth’s axis with its orbital plane is 66¹/₂°

(b) Define rotation and revolution.

Ans. Rotation is the movement of the earth on its axis. On the other hand, the movement of the earth around the sun in a fixed path or orbit is called revolution.

(c) What is a leap year?

Ans. Earth’s takes 365¹/₄ days to complete one revolution around the sun. For convenience, we count 365 days in a year. The remaining six hours of every year are added to make one day over a span of four years. The year to which one day is added has 366 days and it is called a leap year.

(d) Differentiate between Summer and Winter Solstice.

Ans. Differences between summer and winter solstice are as follows:

(e) What is an equinox?

Ans. Direct rays of the sun fall on the equator on 21st March and 23rd September. At this paint, neither of the poles is tilted towards the sun, so, the whole earth experiences equal days and equal nights. This position is called an equinox.

(f) Why does the Southern Hemisphere experience Winter and Summer solstice in different times than that of the Northern Hemisphere?

Ans. On 22nd December Southern Hemisphere is tilted towards the sun, thus there is summer solstice in the Southern Hemisphere. At that time, winter solstice occurs in the Northern Hemisphere when it is away from the sun. On the other hand, the Northern Hemisphere is tilted wards the sun on 21st June. Hence, summer solstice occurs in the Northern Hemisphere. At time winter solstice is in the Southern Hemisphere. So, the Southern Hemisphere experiences water and summer solstice in different times than that of the Northern Hemisphere.

(g) Why do the poles experience about six months day and six months night?

Ans. The poles experience six months day and six months night due to the following reasons: When the Northern Hemisphere is tilted towards the sun, the North Pole remains in the light 24 hours for six months from 21st March to 23rd September. On the other hand, the South Pale does not get light during these six months in the Southern Hemisphere. Thus, its experiences sight for six months. When the Southern Hemisphere is tilted towards the sun, the South Pole mains in light for the whole day (24 hr). This position remains for six months from 23rd September to 21st March.

Q. 2. Tick(✓) the correct option:

(a) The movement of the earth around the sun is known as:

(i) Rotation.

(ii) Revolution.

(iii) Inclination.

Ans. (ii) Revolution.

(b) Direct rays of the sun fall on the equator on:

(i) 21st March.

(ii) 21st June.

(iii) 22nd December.

Ans. (ii) 21st March.

(c) Christmas is celebrated in summer in:

(i) Japan.

(ii) India.

(iii) Australia.

Ans. (ii) Australia.

(d) Cycle of the seasons is caused due to:

(i) Rotation.

(ii) Revolution.

(iii) Gravitation.

Ans (ii) Revolution.

Q. 3. Fill in the blanks:

(a) A leap year has __________number of days.

Ans. 366.

(b) The daily motion of the earth is ________.

Ans. rotation.

(c) The earth travels around the sun in ________orbit.

Ans. its.

(d) The sun’s rays fall vertically on the Tropic _________on 21st June.

Ans. Cancer.

(e) Days are shorter during _______season.

Ans. winter.

THINGS TO DO

Make a drawing to show the inclination of the earth.

SOME OTHER IMPORTANT QUESTIONS FOR EXAMINATION

Q. 1. What do you understand by the inclination of the Earth’s axis?

Ans. The inclination of the earth’s axis is that it is the tilting of the earth’s axis at an angle of 23¹/₂° from the axis or 66¹/₂° from the orbital plane.

Q. 2. On which two days the sun’s rays are vertical on the equator?

Ans. During winter solstice and summer solstice the sun’s rays are vertically on the equator.

Q. 3. What is an equinox?

Ans. An equinox is one of the two days in a year when the direct rays of the sun fall on the equator causing equal day and night all over the globe.

Q. 4. Leap year occurs after how many years?

Ans. Leap year occurs after every four years.

Q. 5. Name the two factors responsible for the occurrence of seasons.

Ans. The two factors responsible for the occurrence of seasons are rotation and revolution.

Q. 6. What is rotation?

Ans. The spinning of the earth on its own axis once in every 24 hours is known as rotation.

Q. 7. What is an axis?

Ans. The imaginary lines, joining the north pole and the south pole passing through the center of the earth is known as axis.

Q. 8. What is the daily motion of the earth called?

Ans. Rotation.

Q. 9. During which season Christmas is celebrated in Australia.

Ans. Summer season.

Q. 10. Which is the longest day of the southern hemisphere?

Ans. 22 December.

Q. 11. Which Tropic receive the direct sun rays in winter?

Ans. Tropic of Capricorn.

Q. 1. Why does earth gets heat and light from the sun?

Ans. The earth gets heat and light from the sun. Because of the spherical shape of the earth only half of it gets light from the sun at a time.

Q. 2. Why does February have 29 days after every 4 years?

Ans. February have 29 days after every 4 years because earth takes 365 days and 6 hours complete one revolution and this time is considered to be one year. We count only 365 days a year and after every four years, the balance of 6 hours adds upto a day (24 hours). This Extra day is added to the month of February. Thus, every four years February has 29 days stead of 28 and the year has 366 days.

Q. 3. In summer days are longer than nights. Why?

Ans. The summer days are longer than nights because:

(a) A large portion of the Northern Hemisphere is getting light from the sun, so it is summer in the regions north of the equator.

(b) On 21st June, the longest day and the shortest night occur at these places.

Q. 4. What is the phenomenon for the occurrence of seasons?

Ans. The phenomenon for the occurrence of seasons is that if the earth’s axis was not inclined, there would be no seasons. It is because of the tilted axis that the two poles are tilted towards the sun at different times resulting in opposite seasons within a year.

Q. 5. What do you understand by winter solstice and summer solstice?

Ans. Winter solstice is the day of 22nd December when the sun is vertically overhead at the Tropic of Capricorn.

Summer solstice is the day of 21st June when the sun is vertically overhead at the Tropic of Cancer.

Q. 6. Define the circle of illumination.

Ans. The circle that divides the day from night on the globe is called the circle of illumination.

Q. 7. What is earth day?

Ans. The period of rotation is known as the earth day. The earth takes about 24 hours to complete one rotation around its axis.

Q. 8. What is the reason for change in seasons?

Ans. Seasons change due to the change in the position of the earth around the sun.

Q. 9. Why does earth gets heat and light from the sun?

Ans. The earth gets heat and light from the sun because of the spherical shape of the earth, ly half of it gets light from the sun at a time.

Q. 10. How is Equinox formed?

Ans. Direct rays of the sun fall on the equator on 21st March and September 23rd. At this Ption, neither of the poles is tilted towards the sun. So, the whole earth experiences equal yes and nights. This is known as equinox.

Q. 1. State three points of difference between rotation and revolution.

Ans. The three points of difference between rotation and revolution:

Q. 2. How the rotation of the earth causes day and night?

Ans. The earth completes one rotation on its axis in 24 hours. While rotating one half of the earth’s surface gets light from the sun and the other half remains dark. So, the lighted half is day and the dark half is night.

Q. 3. What are the effects of revolution?

Ans. The effects of revolution are as under:

(a) Changes in the heat and light distribution on the earth.

(b) Changes of seasons.

(c) Changes in length of days and nights.

Q. 4. How is equinox formed?

Ans. Direct rays of the sun fall on the equator on 21st March and 23rd September. At their position, neither of the poles is tilted towards the sun, so, the whole earth experiences equal days and equal nights. This is known as equinox.

Q. 5. See the diagram of the revolution of the earth and seasons. Mention its parts correctly.

Fig. Revolution of the Earth and Seasons

Q. 6. What would happen if the earth did not rotate?

Ans. If the earth did not rotate, it would have led to the following consequences:

(a) The portion of the earth facing the sun would always experience day, thus bringing continuous warmth to the region.

(b) The other half would remain in darkness and be freezing cold all the time.

(c) Life would not have been possible in such extreme conditions.

HIGH ORDER THINKING SKILLS

Q. 1. Why the Southern Hemisphere had shorter nights and longer days?

Ans. The Tropic of Capricorn receives direct rays of the sun. This is because the South Pole tilts towards it on the day of 22nd December. As the sun’s rays fall vertically at the Tropic of Capricorn (23¹/₂ S) a longer portion of the Southern Hemisphere gets heat and light. As a result, it is summer in the Southern Hemisphere with shorter nights and longer days.

Q. 2. What happen if the earth did not rotate on its axis?

Ans. The sun facing portion of the earth would always experience day, thus bringing continuous warmth to the region. Similarly, the other half would remain in darkness and be freezing cold all the time.

Q. 3. Why the places near the Arctic Circle face continuous daylight for about six months?

Ans. The rays of the sun fall slanting on poles and as a result, the areas near poles receive less heat. The North Pole is inclined towards the sun and the places beyond the Arctic Circle lace continuous day light for about six months.

Q. 4. Why days and nights equal all over the world on 21st March and 23rd September?

Ans. The days and nights are equal all over the world on 21st March and 23rd September because the sun is overhead at the equator and days and nights are equal in length throughout the world on these two dates. 21st March is called Spring Equinox and 23rd September is called Autumnal Equinox.

VALUE BASED QUESTIONS

Q. 1. Why the days and nights would have been of equal length throughout the year all over the world?

Ans. The inclination of the earth’s axis causes varying lengths of day and night. If the earth’s axis were vertical to the plane of the orbit, any place would receive the sun’s rays in the same way all round the year.

Q. 2. Why did earth’s one half has day and other night?

Ans. The earth gets heat and light from the sun. Because of the spherical shape of the earth, only half of it gets light from the sun at a time. The portion facing the sun experiences day and the remaining half portion away from the sun experiences night. Hence, the region between the Arctic Circle and the North Pole experiences a period of only day light with no light.

OBJECTIVE TYPE QUESTIONS

l. MULTIPLE CHOICE QUESTIONS:

Tick (✓) the correct option:

(a) 22nd December is the shortest day in the __________.

(i) Southern Hemisphere.

(ii) Northern Hemisphere.

(iii) Regions near the poles.

(iv) Regions near the equator.

Ans. (i) Southern Hemisphere.

(b) The spinning of the Earth on its axis is called _________.

(i) Rotation.

(ii) Equinox.

(iii) Revolution.

(iv) Solstice.

Ans. (i) Rotation.

(c) The movement of the earth around the sun is called:

(i) Rotation.

(ii) Revolution.

(iii) Circulation.

(iv) Inclination.

Ans. (ii) Revolution.

(d) On 21st June the sun is overhead at __________.

(i) Equator.

(ii) Tropic of Cancer

(iii) Arctic Circle.

(iv) Tropic of Capricorn.

Ans. (ii) Tropic of Cancer.

(e) Days and nights are equal on _________.

(i) 22ⁿᵈ December.

(ii) 21ˢᵗ June.

(iii) 21ˢᵗ March.

(iv) 20ᵗʰ September.

Ans. (iii) 21ˢᵗ March.

II. FILL IN THE BLANKS:

(a) The earth rotates from _________.

Ans. east to west.

(b) A leap year has ________days.

Ans. 29

(e) Seasons are caused by ________and ________of the Earth.

Ans. Rotation, Revolution.

(d) The spinning of the earth on its axis is called _________.

Ans. Rotation.

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