Class 4 EVS Chapter 10 Our Sky – Revision Notes

Class 4 EVS Chapter 10, Our Sky, introduces the sun, moon, stars, and basic day-night and seasonal changes, building early awareness of astronomy and the sky above us.

Last Updated: September 23, 2026

About Chapter 10: Our Sky

The sky changes constantly — day to night, clear to cloudy, and across seasons — and this chapter helps students observe and understand some of the simple, regular patterns behind those changes.

Key Concepts

1. The Sun

The sun is a star that provides light and heat to the Earth, appears to rise in the east and set in the west (due to Earth’s rotation), and is essential for life, weather, and the day-night cycle.

2. The Moon

The moon orbits the Earth and reflects sunlight rather than producing its own light, appearing to change shape over about a month — these different shapes are called phases of the moon (new moon, crescent, half, full moon, and back again).

3. Stars

Stars are distant, glowing balls of gas visible at night when the sky is dark and clear; they appear as tiny points of light because they are extremely far away, even though many are much larger than the sun.

4. Day and Night

Day and night occur because the Earth rotates on its axis — the side facing the sun experiences day, while the side facing away experiences night, completing a full cycle approximately every 24 hours.

5. Seasons

Seasons change through the year due to the Earth’s tilt and its orbit around the sun, affecting temperature, daylight hours, and weather patterns differently across the year.

6. Clouds and Weather

Clouds form from water vapour and can indicate upcoming weather — fluffy white clouds often mean fair weather, while dark, heavy clouds often signal rain.

Quick Recap

• The sun is a star that provides light, heat, and drives the day-night cycle.
• The moon reflects sunlight and appears to change shape (phases) over about a month.
• Stars are distant glowing balls of gas, visible mainly at night.
• Day and night result from the Earth’s rotation on its axis.
• Seasons change due to the Earth’s tilt and its orbit around the sun.

Common Mistakes to Avoid

A common misconception is thinking the moon produces its own light — it actually reflects sunlight. Another common error is confusing the cause of day-night (Earth’s rotation on its axis) with the cause of seasons (Earth’s tilt and its orbit around the sun) — these are two different, related but distinct, phenomena.

How to Practise This Chapter at Home

Observe the moon’s shape on several nights over a couple of weeks and note how it changes, connecting the observation to the idea of moon phases. Watch the sky at different times of day and discuss the position of the sun, and on a clear night, look for stars and talk about how far away they are.

Why This Chapter Matters

Early exposure to astronomy builds curiosity about space and science, and understanding the sun, moon, and basic sky patterns lays groundwork for more detailed study of the solar system and Earth’s movements in later classes.

Frequently Asked Questions

Does the moon produce its own light?
No — the moon reflects light from the sun; it does not generate its own light.

Why does the moon appear to change shape?
Because as the moon orbits the Earth, different amounts of its sunlit side become visible from Earth, creating the different phases we see over about a month.

What causes day and night?
The Earth’s rotation on its own axis — the side facing the sun experiences day, while the opposite side experiences night.

What causes the seasons to change?
The tilt of the Earth’s axis combined with its yearly orbit around the sun causes different parts of the Earth to receive varying amounts of sunlight at different times of the year.

Why can we usually only see stars at night?
Because the sun’s much brighter light during the day outshines the faint light of distant stars, making them invisible until the sky darkens.

See the Chapter 10 Solutions for the full textbook walkthrough.

Written by Satish

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