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 axial tilt, as it revolves 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 tilted about 23.5° from the perpendicular to its orbital plane. As Earth revolves around the Sun, this tilt changes the angle and duration of sunlight in each hemisphere, producing 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 20–21 March and 22–23 September, day and night are approximately equal (equinoxes). Exact dates vary slightly by year.

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?

ANSWERIn Fig. 12.17, the North Pole lies on the dark side and the South Pole lies on the sunlit side. During one full rotation of Earth:North Pole: 0 hours of sunlight. It remains in polar night.South Pole: 24 hours of sunlight. It remains in continuous daylight.This is the December-solstice configuration, with the North Pole tilted away from the Sun. Do not swap it with the June configuration.
December configuration: North Pole in darkness for 24 hours and South Pole in sunlight for 24 hours; June reverses this.
Polar daylight: the left panel explains NCERT Fig. 12.17; the right panel shows the opposite season. Tap to view at full size.

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).

The expected fill-ins are East and West. Stars close enough to the celestial pole can remain above the horizon all night at a given location; these are called circumpolar stars.

(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.

ANSWERFalse. Looking at the bright Sun without proper solar protection can seriously injure the eyes. Use supervised projection or suitable solar viewers; ordinary sunglasses are not suitable. See the safety note under Question 7.

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

ANSWERTrue. As Earth revolves around the Sun with its axis tilted, the hemispheres receive sunlight at changing angles and for changing durations. This produces opposite seasons in the two hemispheres.

(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.

More precisely, Earth turns once relative to distant stars in about 23 hours 56 minutes. The average solar day is 24 hours, so a star returns to nearly the same position about 4 minutes earlier each night.

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?

ANSWEREarth rotates from West to East. The side facing the Sun has day while the side turned away has night.India and the USA are far apart in longitude, so their day-and-night cycles occur at different clock times. This explains Abhay’s observation. The USA spans several time zones; it is not night everywhere in the USA throughout every hour of India’s daytime.

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.

ANSWERAdithya (iii) was careless because he looked directly at the Sun without protection.The other methods are appropriate only when correctly arranged and supervised. Solar viewers must be suitable for Sun viewing, mirror projection must direct the image safely onto a screen, and a planetarium programme requires following its safety instructions.

Safe solar-eclipse observation

Whenever any bright part of the Sun is visible, use undamaged solar viewers meeting ISO 12312-2 from a reputable supplier, with adult supervision. Ordinary sunglasses are unsuitable. Never combine eclipse glasses with binoculars, a telescope or a camera; optical devices require correctly fitted front-mounted solar filters and expert guidance. For projection, look only at the image on a screen, never through the hole or into a reflected beam. Lunar eclipses are safe to watch without solar filters.

Further guidance: NASA eclipse eye-safety advice.

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
Solar eclipse order Sun, Moon, Earth; lunar eclipse order Sun, Earth, Moon.
For Question 8, identify the middle body: Moon for a solar eclipse, Earth for a lunar eclipse. Sizes and distances are not to scale. Tap to view at full size.

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?

ANSWERA lunar eclipse is visible from places where the Moon is above the horizon during the event, weather permitting. A large part of Earth can therefore see the same eclipsed Moon.A total solar eclipse is visible only within the narrow path of the Moon’s central dark shadow (umbra) on Earth. A much wider surrounding region can see a partial solar eclipse.

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

ANSWERWithout axial tilt, there would be no familiar tilt-driven summer and winter seasons. At any particular latitude, the Sun’s daily path and day length would change very little through the year.This does not mean every place would receive equal sunlight: the equator would still receive more direct rays than high latitudes. Away from the poles, day and night would each be roughly 12 hours; at the poles the Sun would stay near the horizon. The small variation in Earth–Sun distance would still remain.

Extra Practice Questions

These questions and MCQs are ClearStudy practice, separate from the NCERT exercise.

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 look at the Moon, whose reflected light is safe to view without solar filters. During a solar eclipse, any visible bright portion of the Sun can injure the eyes; use the supervised safe methods described above.

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 turning gives most places a daily cycle of day and night. Polar regions are an exception during parts of the year: axial tilt can keep them in continuous daylight or darkness for many days. 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 total solar eclipse is visible from only a small region.

ANSWERDuring a solar eclipse, the Moon lies between the Sun and Earth, and its shadow reaches Earth. Only the narrow umbral path sees totality; the surrounding penumbra sees a partial eclipse.During a lunar eclipse, Earth lies between the Sun and Moon and the Moon passes through Earth’s shadow. It may darken partly or fully; during totality it often looks reddish because some sunlight is bent and filtered through Earth’s atmosphere.A lunar eclipse can be seen wherever the Moon is above the horizon during the event, while total solar-eclipse visibility is restricted to the narrow moving shadow path.

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 — together with axial tilt, produces seasons and changes which stars are visible at night).
  • 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 write a clear answer

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 approximate Northern Hemisphere dates (around 21 June summer solstice, 21–22 December winter solstice, 20–21 March and 22–23 September equinoxes) 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 axial tilt, as it revolves 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 Earth turns, most places move between the lit and dark sides. Polar regions can have continuous daylight or darkness during parts of the year because of axial tilt.

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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