NCERT Solutions for Class 7th Science Chapter 12 Earth, Moon, and the Sun
Updated on 2026-09-19
About this chapter
The Earth rotates on its own axis — an imaginary line through the geographic North Pole and South Pole — once in about 24 hours . Seen from above the North Pole, this rotation is anti-clockwise, that is, from West to East . Because we watch the sky from a rotating Earth, the Sun, the Moon and the stars only appear to move. They seem to rise in the East and set in the West . This is exactly like the trees appearing to turn the other way when you ride a merry-go-round. The Earth's rotation causes the day–night cycle : the half facing the Sun has day, the other half has night. The Earth's axis points very close to the Pole Star (Dhruva Tara) , so that star appears almost fixed while all other stars, such as the Big Dipper (Saptarishi) , appear to swing around it. The Earth also revolves aroun
- Chapter opener
- .1 Rotation of the Earth
- and 17212.1 Rotation of the Earth
- .2 Revolution of the Earth
- .2.2 Seasons on the Earth
- .3 Eclipses
- .3.1 Solar eclipse
- Dive Deeper boxes of the chapter
- .3.2 Lunar eclipse
- Know a Scientist: M.K. Vainu Bappu
Quick revision
| Term | What it means | Example / detail from the chapter | Point to remember |
|---|---|---|---|
| Rotation | The motion of an object in which all its parts move in circles around an imaginary line passing through it | A spinning top, a ceiling fan, a ball spun on a finger — and the Earth, once in about 24 hours | The imaginary line is called the axis of rotation |
| Earth's axis of rotation | The line through the geographic North Pole and the South Pole about which the Earth spins | Viewed from above the North Pole the Earth turns anti-clockwise, West to East | It is tilted with respect to the orbit, and it points very close to the Pole Star |
| Revolution | The motion of an object around another object | The Earth around the Sun in about 365 days and 6 hours; the Moon around the Earth | Rotation is spinning on its own axis; revolution is going around something else |
| Orbit | The path an object takes while revolving around another object | Seen from the top, the Earth's orbit around the Sun is nearly circular | It looks elongated in books only because that picture is a side view |
| Day and night | The lit half of the Earth has day, the dark half has night | Sunrise as your place turns into the light, sunset as it turns into the dark (Fig. 12.5) | Caused by rotation — not by revolution |
| Pole Star (Dhruva Tara) | The star lying almost exactly along the Earth's axis in the Northern Hemisphere | The Big Dipper (Saptarishi) appears to circle around it through the night (Fig. 12.7) | It appears nearly stationary because the axis points at it |
| Seasons | The yearly cycle of summer, winter and the rest | June: Northern Hemisphere tilted towards the Sun — summer; December — winter | Caused by the tilt of the axis plus the spherical shape of the Earth |
| Solstice | The day with the longest or the shortest daytime | About 21 June (summer solstice) and 22 December (winter solstice) in the Northern Hemisphere | On 21 June the North Pole gets sunlight for all 24 hours |
| Equinox | A day on which daytime lasts about 12 hours everywhere | Around 21 March (spring) and 23 September (autumn) in the Northern Hemisphere | The equator has nearly 12 hours of daylight on every day of the year |
| Apparent size | The size of an object as seen by the eye | A thumb can cover a friend's head 5 m away (Activity 12.4) | It depends on the actual size and the distance from the observer |
| Solar eclipse | The Moon comes between the Sun and the Earth and blocks sunlight from reaching us | Total in the small dark region, partial around it (Fig. 12.13) | Never view it directly — use only a projected image or approved eclipse goggles |
| Lunar eclipse | The Earth comes between the Sun and the Moon so the Earth's shadow falls on the Moon | Total lunar eclipse — the Moon turns dark red (Fig. 12.16) | Perfectly safe to watch with the naked eye |
Exercises
- Chapter opener — In-text Question Page 169
- .1 Rotation of the Earth — In-text Questions Page 17012
- .1 Rotation of the Earth — Activity 12.1: Let us explore Page 17012
- .1 Rotation of the Earth — In-text Question Page 17112
- and 17212.1 Rotation of the Earth — Activity 12.2: Let us explore Page 171
- .1 Rotation of the Earth — In-text Question Page 17312
- .1 Rotation of the Earth — In-text Question Page 17412
- .1 Rotation of the Earth — Activity 12.3: Let us explore Page 17412
- .2 Revolution of the Earth — In-text Question Page 17512
- .2.2 Seasons on the Earth — In-text Question Page 17712
- .3 Eclipses — In-text Question Page 17912
- .3.1 Solar eclipse — Activity 12.4: Let us explore Page 18012
- Dive Deeper boxes of the chapter — Dive Deeper Page 171 to 186
- .3.2 Lunar eclipse — Science and Society Page 18312
- Know a Scientist: M.K. Vainu Bappu — Know a Scientist Page 184
- Chapter exercises — Let Us Enhance Our Learning Page 184 to 186
- Interdisciplinary projects — Exploratory Projects Page 186