NCERT Solutions for Class 7 Science (Curiosity) Chapter 12: Earth, Moon, and the Sun (NCERT 2026–27)

These Class 7 Science Curiosity Chapter 12 solutions cover Earth, Moon, and the Sun from the new NCF-2023 textbook (2026–27). The chapter explains why the Sun, Moon and stars appear to move across the sky, how the Earth’s rotation gives us day and night, how its tilted revolution around the Sun produces seasons, and how solar and lunar eclipses occur. Every textbook question from the “Let Us Enhance Our Learning” exercise is reproduced verbatim and solved below with clear, exam-ready answers.

Class: 7 Subject: Science Book: Curiosity Chapter: 12 Topic: Earth’s rotation, revolution, seasons & eclipses Session: 2026–27
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Class 7 Science Curiosity Chapter 12 Solutions – Overview

Chapter 12 of Curiosity, Earth, Moon, and the Sun, answers a puzzle many of us have wondered about: does the Sun really travel across the sky, or is it the Earth that moves? Using the everyday example of a spinning merry-go-round, the chapter shows that the Earth rotates on its own axis from West to East once in about 24 hours, which makes the Sun, Moon and stars appear to rise in the East and set in the West, and which causes the cycle of day and night. The Earth also revolves around the Sun once in about 365 days and 6 hours along a nearly circular orbit. Because the Earth’s axis is tilted and its surface is spherical, different parts receive sunlight of different intensity and for different lengths of time during the year — this gives rise to seasons. Finally, the chapter explains eclipses: a solar eclipse when the Moon blocks the Sun’s light from reaching the Earth, and a lunar eclipse when the Earth blocks sunlight from reaching the Moon.

Key Concepts & Definitions

Rotation: the motion of an object in which all its parts move in circles around an imaginary line (the axis of rotation) passing through it. The Earth completes one rotation in about 24 hours.

Axis of rotation: the imaginary line through the Earth’s geographic North Pole and South Pole about which the Earth spins.

Day and night: caused by the Earth’s rotation from West to East — the half facing the Sun has day, the other half has night.

Revolution: the motion of one object around another. The Earth revolves around the Sun once in about 365 days and 6 hours.

Orbit: the path an object takes while revolving around another object; the Earth’s orbit around the Sun is nearly circular.

Tilt of the axis: the Earth’s axis is not upright with respect to its orbit but is tilted; this tilt, together with the Earth’s spherical shape, gives rise to seasons.

Solstice & equinox: in the Northern Hemisphere the longest day (summer solstice) is around 21 June and the shortest day (winter solstice) around 22 December; around 21 March and 23 September day and night are each 12 hours (spring and autumn equinox).

Solar eclipse: occurs when the Moon comes between the Sun and the Earth and blocks the Sun’s light from reaching the Earth.

Lunar eclipse: occurs when the Earth comes between the Sun and the Moon and blocks sunlight from reaching the Moon.

“Let Us Enhance Our Learning” — NCERT Solutions

All questions below are reproduced exactly as printed in the NCERT Curiosity textbook (Grade 7); the answers are original and written in exam-ready style.

1. In Fig. 12.17, how many hours of sunlight do the North Pole and the South Pole receive during one rotation of the Earth?

ANSWER Fig. 12.17 shows the June position, when the Earth’s North Pole is tilted towards the Sun. In this position, during one full (24-hour) rotation of the Earth: North Pole: receives sunlight for all 24 hours — it stays in continuous daylight. South Pole: receives sunlight for 0 hours — it remains in complete darkness for all 24 hours.

2. Fill in the blanks

(i) Stars rise in the _________ and set in the ___________.

ANSWER Stars rise in the East and set in the West (because the Earth rotates from West to East).

(ii) Day and night are caused by the Earth’s __________________.

ANSWER Day and night are caused by the Earth’s rotation (about its own axis, from West to East).

(iii) When the Moon fully covers the Sun from our view, it is called a _____________ solar eclipse.

ANSWER When the Moon fully covers the Sun from our view, it is called a total solar eclipse.

3. State whether True or False

(i) Lunar eclipse occurs when the Sun comes between the Earth and the Moon.

ANSWER False. A lunar eclipse occurs when the Earth comes between the Sun and the Moon, blocking sunlight from reaching the Moon.

(ii) Sunrise happens earlier in Gujarat than in Jharkhand.

ANSWER False. The Earth rotates from West to East, so sunrise occurs first in the eastern parts of India. Jharkhand lies to the east of Gujarat, so sunrise happens earlier in Jharkhand than in Gujarat.

(iii) In Chennai, the longest day occurs on the summer solstice.

ANSWER True. Chennai lies in the Northern Hemisphere, where the longest day occurs around the summer solstice (about 21 June). (Being close to the equator, the difference in day length there is small, but the longest day still falls on the summer solstice.)

(iv) We should watch the solar eclipse directly with our naked eye.

ANSWER False. Even during an eclipse the Sun is intense enough to damage the eyes and cause blindness. A solar eclipse must never be viewed directly, nor through sunglasses, binoculars or telescopes.

(v) Seasons occur due to the tilt of Earth’s axis of rotation and its spherical shape.

ANSWER True. The tilt of the Earth’s axis and the spherical shape of the Earth together cause the seasons.

(vi) The Earth’s revolution around the Sun causes day and night.

ANSWER False. Day and night are caused by the Earth’s rotation, not its revolution. Revolution (along with the axial tilt) causes the seasons and the changing night sky.

4. Padmashree saw the Orion constellation nearly overhead at 8 pm yesterday. When will she see Orion overhead today?

ANSWER Because the Earth also revolves around the Sun, a given star appears in the same position in the sky a little earlier each night — by about 4 minutes per day. So today Padmashree will see Orion nearly overhead at about 4 minutes before 8 pm, i.e. around 7:56 pm.

5. Nandhini saw a group of stars rising at midnight on 21 June. When will she see the same group of stars rising at midnight next year?

ANSWER The Earth completes one revolution around the Sun in about one year and returns to the same position in its orbit. The pattern of stars in the night sky therefore repeats over a year. So Nandhini will see the same group of stars rising at midnight again on about 21 June next year (the same date the following year).

6. Abhay noticed that when it was daytime in India, his uncle who was in the USA was generally sleeping as it was night-time there. What is the reason behind this difference?

ANSWER The Earth is a sphere that rotates on its axis, so at any moment only one half of the Earth faces the Sun and has day, while the other half is turned away and has night. India and the USA lie on nearly opposite sides of the Earth. When India faces the Sun (daytime), the USA is on the dark side facing away from the Sun (night-time). This is why it is day in India when it is night in the USA.

7. Four friends used the following ways to see the solar eclipse. Who among them was being careless?

(i) Ravikiran used a solar eclipse goggle.

(ii) Jyothi used a mirror to project the Sun’s image.

(iii) Adithya saw the Sun directly with his eyes.

(iv) Aruna attended a programme arranged by a planetarium.

ANSWER Adithya (iii) was being careless. Looking at the Sun directly with the naked eye during a solar eclipse can damage the eyes and cause blindness. The other three were safe: solar-eclipse goggles give proper eye protection, projecting the Sun’s image with a mirror avoids looking at the Sun directly, and a planetarium programme provides specialised protection and supervision.

8. Fill in the circles in Fig. 12.18 appropriately with one of the following: Sun, Moon, Earth.

ANSWER Solar eclipse: the order is Sun — Moon — Earth. The Sun is given; the next (middle) circle is the Moon, and the last circle is the Earth. (The Moon comes between the Sun and the Earth.) Lunar eclipse: the order is Sun — Earth — Moon. The Moon is given; the first circle is the Sun and the middle circle is the Earth. (The Earth comes between the Sun and the Moon.)
ArrangementFirstMiddleLast
Solar eclipseSunMoonEarth
Lunar eclipseSunEarthMoon

9. The Moon is much smaller than the Sun, yet it can block the Sun completely from our view during a total solar eclipse. Why is it possible?

ANSWER The apparent size of an object (its size as seen by the eye) depends both on its actual size and on its distance from us — a nearer object looks bigger. Although the Moon is much smaller than the Sun in physical size, it is also much closer to the Earth than the Sun is. As a result, the apparent sizes of the Moon and the Sun in our sky are nearly the same, so the Moon can appear to cover the entire Sun during a total solar eclipse.

10. The Indian cricket team matches in Australia are often held in December. Should they pack winter or summer clothes for their trip?

ANSWER Australia lies in the Southern Hemisphere, where the seasons are the reverse of those in the Northern Hemisphere (India). In December the Southern Hemisphere is tilted towards the Sun, so it is summer in Australia. Therefore the team should pack summer clothes.

11. Why do you think lunar eclipses can be seen from a large part of the Earth when they happen, but total solar eclipse can be seen by only a small part of the Earth?

ANSWER During a lunar eclipse, the Earth’s shadow falls on the Moon. As long as the Moon is above the horizon, anyone on the entire night side of the Earth can see the eclipsed Moon, so it is visible from a large part of the Earth. During a total solar eclipse, it is the Moon’s shadow that falls on the Earth, and this shadow covers only a small area of the Earth’s surface. Only observers within that small region see the total eclipse, so it is visible from only a small part of the Earth.

12. If the Earth’s axis were not tilted with respect to the axis of revolution, explain what would be the effect on seasons?

ANSWER The seasons arise mainly because the tilt of the Earth’s axis makes the two hemispheres receive sunlight of changing intensity and for changing lengths of time through the year. If the axis were not tilted (upright with respect to the orbit), every place on the Earth would receive nearly the same amount of sunlight for the same number of hours throughout the year. There would be no seasons — conditions at each place would stay almost the same all year round, and day and night would be roughly equal everywhere.

Extra Practice Questions

Short Answer Type Questions

Q1. Define rotation of the Earth and state how long it takes.

ANSWERRotation is the spinning of the Earth on its own axis — an imaginary line through the North and South Poles. The Earth completes one rotation in about 24 hours.

Q2. In which direction does the Earth rotate, and what does this make the Sun appear to do?

ANSWERThe Earth rotates from West to East (anti-clockwise as seen from above the North Pole). This makes the Sun appear to rise in the East, move across the sky, and set in the West.

Q3. Why does the Pole Star appear almost stationary in the night sky?

ANSWERThe Earth’s axis of rotation points very close to the Pole Star in the Northern Hemisphere. Because the axis is aimed at it, the Pole Star appears nearly fixed while all other stars seem to move around it.

Q4. State the difference between rotation and revolution of the Earth.

ANSWERRotation is the spinning of the Earth on its own axis (once in about 24 hours), causing day and night. Revolution is the movement of the Earth around the Sun (once in about 365 days and 6 hours), which, with the axial tilt, causes the seasons.

Q5. Why can we safely watch a total lunar eclipse with the naked eye but not a solar eclipse?

ANSWERDuring a lunar eclipse we see only the dimly lit (dark red) Moon, which is safe to view. During a solar eclipse we would be looking towards the Sun, whose intense light can damage the eyes and cause blindness, so it must never be viewed directly.

Long Answer Type Questions

Q1. Explain how the Earth’s rotation causes the cycle of day and night.

ANSWERThe Earth is a sphere that spins on its axis from West to East, completing one rotation in about 24 hours. At any moment, the Sun’s light can reach only the half of the Earth that faces it; that half experiences daytime, while the half turned away from the Sun stays dark and experiences night. As the Earth rotates, a place moves from the dark side into the lit side — this is sunrise — and later moves back into darkness — this is sunset. This continuous turning gives every place a regular cycle of day followed by night. Because the rotation is from West to East, the Sun appears to rise in the East and set in the West.

Q2. How do the tilt of the Earth’s axis and its spherical shape produce seasons? Use the example of June and December.

ANSWERThe Earth’s axis is tilted with respect to its orbit, and the Earth keeps this tilt as it revolves around the Sun. In June, the Northern Hemisphere is tilted towards the Sun. Because of the Earth’s spherical shape, the same amount of sunlight is spread over a smaller area there, making it more intense; the Northern Hemisphere also receives sunlight for more than 12 hours. This intense, long-lasting sunlight causes summer in the Northern Hemisphere. In December the situation is reversed: the Northern Hemisphere is tilted away from the Sun, sunlight is spread over a larger area (less intense) and lasts for fewer hours, causing winter. The Southern Hemisphere always experiences the opposite seasons. Thus the axial tilt and the spherical shape together cause the seasons.

Q3. Describe how a solar eclipse and a lunar eclipse occur, and explain why a solar eclipse is visible from only a small region.

ANSWERA solar eclipse occurs when the Moon comes between the Sun and the Earth and blocks the Sun’s light from reaching us; the Moon’s shadow falls on a small area of the Earth, where observers see the Sun darkened. A lunar eclipse occurs when the Earth comes between the Sun and the Moon and blocks sunlight from reaching the Moon; the Earth’s shadow falls on the full Moon, which turns dark red. A solar eclipse is visible only from a small region because the Moon’s shadow on the Earth covers only a small area, and the Earth’s rotation and the Moon’s motion sweep this shadow quickly across the surface, so the total eclipse lasts only a few minutes at any place. A lunar eclipse, by contrast, is visible from the whole night side of the Earth because everyone facing the Moon can see it darkened.

MCQs & Answer Key

1. The Earth completes one rotation on its axis in about:

(a) 1 hour    (b) 24 hours    (c) 365 days    (d) 1 month

2. The Earth rotates in which direction?

(a) East to West    (b) North to South    (c) West to East    (d) South to North

3. Day and night on the Earth are caused by its:

(a) revolution    (b) rotation    (c) tilt    (d) spherical shape

4. The Earth completes one revolution around the Sun in about:

(a) 24 hours    (b) 30 days    (c) 365 days and 6 hours    (d) 100 years

5. Seasons on the Earth occur mainly because of:

(a) the Earth’s rotation    (b) changing distance from the Sun    (c) the tilt of the axis and the spherical shape    (d) the Moon

6. In the Northern Hemisphere, the longest day (summer solstice) occurs around:

(a) 22 December    (b) 21 June    (c) 21 March    (d) 23 September

7. A solar eclipse occurs when:

(a) the Earth is between the Sun and the Moon    (b) the Moon is between the Sun and the Earth    (c) the Sun is between the Earth and the Moon    (d) the stars block the Sun

8. A lunar eclipse occurs when:

(a) the Moon is between the Sun and the Earth    (b) the Earth is between the Sun and the Moon    (c) the Sun is between the Earth and the Moon    (d) Venus blocks the Sun

9. The Pole Star appears almost stationary because:

(a) it does not exist    (b) the Earth’s axis points very close to it    (c) it is the brightest star    (d) it is the closest star

10. The Moon can cover the Sun during a total solar eclipse because:

(a) the Moon is larger than the Sun    (b) the Moon is hotter    (c) the Moon is closer, so its apparent size is similar to the Sun’s    (d) the Sun shrinks

Answer key: 1-(b), 2-(c), 3-(b), 4-(c), 5-(c), 6-(b), 7-(b), 8-(b), 9-(b), 10-(c).

Assertion–Reason Questions

For each Assertion–Reason question, choose: (A) Both true and the Reason correctly explains the Assertion; (B) Both true but the Reason is not the correct explanation; (C) Assertion true, Reason false; (D) Assertion false, Reason true.

A-R 1. Assertion: The Sun appears to move across the sky from East to West.

Reason: The Earth rotates on its axis from West to East.

A-R 2. Assertion: Day and night are caused by the revolution of the Earth around the Sun.

Reason: Only the half of the Earth facing the Sun receives sunlight at a time.

A-R 3. Assertion: When it is summer in India, it is winter in Australia.

Reason: The two hemispheres are tilted towards or away from the Sun in opposite ways, so their seasons are reversed.

A-R 4. Assertion: A total solar eclipse is visible from only a small part of the Earth.

Reason: The Moon’s shadow falls on only a small area of the Earth’s surface.

A-R 5. Assertion: We can safely watch a total lunar eclipse with the naked eye.

Reason: During a lunar eclipse we view the dimly lit Moon and not the intense Sun.

Answer key: 1-(A), 2-(D), 3-(A), 4-(A), 5-(A).

Common Mistakes to Avoid

Watch out for these

  • Confusing rotation (spinning on its axis — causes day/night) with revolution (moving around the Sun — causes seasons and the changing night sky).
  • Thinking seasons happen because the Earth is closer to the Sun in summer — they are caused by the tilt of the axis; in fact the Earth is closest to the Sun in January.
  • Writing that a lunar eclipse is when the Sun comes between Earth and Moon — it is the Earth that comes between the Sun and the Moon.
  • Saying sunrise happens earlier in the western parts of India — it happens earlier in the eastern parts, because the Earth turns from West to East.
  • Believing the Moon is bigger than the Sun because it can cover it — the Moon only has a similar apparent size because it is much closer.
  • Thinking it is safe to view a solar eclipse directly or through sunglasses/binoculars — it can cause blindness and must be avoided.

How to score full marks in this chapter

Always link the right motion to the right effect: rotation → day & night and the apparent movement of Sun, Moon and stars; revolution + axial tilt → seasons and the changing night sky. In eclipse answers, name the middle body clearly (Moon in the middle for a solar eclipse, Earth in the middle for a lunar eclipse) and use the words “blocks the light from reaching”. Remember the key dates (21 June summer solstice, 22 December winter solstice, 21 March & 23 September equinox) and that the Southern Hemisphere has reversed seasons.

Frequently Asked Questions

What is Class 7 Science Curiosity Chapter 12 about?

Chapter 12, Earth, Moon, and the Sun, explains why the Sun, Moon and stars appear to move across the sky, how the Earth’s rotation causes day and night, how its tilted revolution around the Sun produces seasons, and how solar and lunar eclipses occur.

Why does the Earth’s rotation cause day and night?

The Earth spins on its axis from West to East once in about 24 hours. Only the half facing the Sun gets sunlight (day), while the other half is dark (night). As the Earth turns, each place moves between the lit and dark sides, giving a regular cycle of day and night.

Why is there no eclipse every month even though the Moon orbits the Earth?

Eclipses occur only when the Sun, Earth and Moon line up closely. The Moon’s orbit is slightly tilted, so usually the Moon passes a little above or below this line, and its shadow (or the Earth’s shadow) misses. Eclipses happen only on the occasions when they line up well enough.

Are these Class 7 Science Curiosity Chapter 12 solutions free?

Yes. All solutions are free and follow the official NCERT Curiosity textbook for 2026–27.

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