CBSE Class 7 Science Chapter 12 Earth, Moon, and the Sun Notes 2025-26

The relationship between the Earth, Moon, and Sun shapes many of the natural phenomena we observe daily—such as day and night, changing seasons, and eclipses. Understanding these interactions helps explain why the Sun appears to rise in the east and set in the west, and how the night sky changes through the year. This chapter revises core concepts about the Earth's rotation and revolution, and how these movements affect life on our planet.

Earth’s Rotation Earth spins on its own axis, an invisible line passing through the North and South Poles. One complete rotation takes about 24 hours. As the Earth rotates from west to east, different parts of its surface move into and out of sunlight, causing day and night alternately. This rotation gives us the regular pattern of sunrise and sunset and also makes the Sun, Moon, and stars appear to move across the sky from east to west.

Objects on the surface (like trees or buildings) appear to move in the opposite direction to the rotation because we are moving with the Earth. Practical activities using a merry-go-round or a spinning globe help visualize how the rotation works and why shadows change length during the day.

Day and Night Cycle When the Sun illuminates half of the Earth's sphere, it is daytime on that half and nighttime on the other. As the Earth rotates, locations move from the dark side into sunlight, resulting in sunrise. As they continue rotating, they move back into darkness, causing sunset. This west-to-east rotation is why the Sun first rises in the eastern part of any country.

At the Equator, people observe the Sun appearing in the east in the morning, directly overhead at noon, and setting in the west by evening. The apparent motion of the Sun is caused by the Earth's spin, not by the Sun actually moving around us. The same effect explains why stars and the Moon seem to rise and set each day.

Apparent Motion of Stars The axis of Earth’s rotation points almost exactly at the Pole Star (Dhruva Tara), so the Pole Star seems fixed in the sky while other stars appear to revolve around it. This is visible as curved star trails in long-exposure night sky photos. Ancient astronomers like Aryabhata also described this apparent movement, comparing it to how trees on a riverbank ‘move backward’ when seen from a moving boat.

Throughout the year, the stars we see at sunset change gradually. This happens because the Earth not only rotates but also revolves around the Sun, shifting our viewpoint in space.

Earth’s Revolution The Earth moves in a nearly circular orbit around the Sun, completing one revolution in about 365 days and 6 hours (one year). Revolution is different from rotation: in revolution, the Earth is moving around another object (the Sun), while in rotation, it turns on its own axis.

Because of Earth’s revolution, the night sky changes gradually over a year. We see different sets of constellations and stars at different times as our position in space changes. For instance, some star groups serve as indicators of seasonal changes in many indigenous cultures.

Seasons and Tilt of the Axis The axis of Earth is tilted at about 23.5 degrees relative to the plane of its orbit. This tilt, along with its spherical shape, causes the seasons. When the northern half of the Earth (Northern Hemisphere) tilts towards the Sun—in June—it receives more direct sunlight and experiences summer, while the Southern Hemisphere experiences winter. In December, the tilt is reversed, giving the Southern Hemisphere summer and the Northern Hemisphere winter. Around March 21 and September 23 (equinoxes), both hemispheres receive roughly equal sunlight, resulting in almost equal day and night lengths worldwide.

Equatorial regions get approximately 12 hours of daylight and 12 hours of night throughout the year, so the difference between seasons is minimal near the Equator. Poles experience extreme variations—long continuous daylight or darkness during their respective summers and winters.

Common Misconceptions about Seasons Seasons do not occur because the Earth is closer to the Sun in summer and farther away in winter. Actually, the Earth is closest to the Sun in January but experiences winter in India during this time. The tilt of the axis and not the distance causes seasonal temperature and sunlight differences.

Eclipses Sometimes, the Sun or Moon gets temporarily hidden because of the relative positions of the Earth, Moon, and Sun.

• Solar eclipse: Occurs when the Moon comes directly between the Sun and the Earth, casting a shadow on the Earth. For a brief time and in a small area, the Sun is completely or partially blocked.
• Lunar eclipse: Happens when Earth comes between the Sun and the Moon, blocking sunlight from reaching the Moon. This may cause the full Moon to appear dark red.

Solar eclipses are rare at any single location, and precautions are necessary because looking directly at the Sun is dangerous for the eyes. Special glasses or indirect viewing are needed. Lunar eclipses are safe to observe with the naked eye and can be seen from more places on Earth at one time.

Key Points Summary

• Earth rotates on its axis in about 24 hours, giving us day and night.
• Earth’s revolution around the Sun takes nearly one year and shapes the gradual changing patterns in the night sky.
• The axis of Earth is tilted, leading to different seasons in the Northern and Southern Hemispheres.
• The Equator experiences almost equal days and nights all year; poles can have months of day or night.
• Solar eclipses happen when the Moon blocks the Sun’s light to Earth; lunar eclipses occur when the Earth blocks sunlight from reaching the Moon.

Famous Indian astronomers, such as Aryabhata, and institutions like the Kodaikanal Solar Observatory have contributed to our understanding of these phenomena. Safe observation practices during solar eclipses and recognizing how the Earth’s movements affect our daily life are important aspects of this chapter.

Class 7 Science Chapter 12 Notes – Earth, Moon, and the Sun: Key Points for Quick Revision

These Class 7 Science Chapter 12 notes simplify important facts about the Earth, Moon, and Sun, guiding you through rotation, revolution, and eclipses in easy language. With clearly listed key points and real-life examples, revision becomes more effective and focused. Reviewing these notes helps you quickly remember concepts for tests and assignments.

Prepared using the latest NCERT guidelines, these revision notes offer a structured summary and clear explanations for CBSE Class 7 Science Chapter 12. Strengthen your understanding of earth’s movements, seasons, and eclipses through concise summaries and exam-oriented information, ideal for last-minute preparation and classroom discussions.