Our Sky — Class 4 EVS (CBSE)
From the current NCERT Our Wondrous World Grade 4 book, Unit 5: Our Environment, Chapter 10. Look up at the sky — by day and by night — and discover its wonders.
1. Why this chapter matters
The sky is full of wonders — the Sun, Moon, and stars. Learning about them, about day and night, and about the changing Moon builds curiosity and a love for nature and space.
2. Key ideas
- By day we see the Sun; by night we see the Moon and stars.
- The Sun gives us light and heat and makes the day bright and warm.
- Day and night happen because the Earth spins (rotates) — the side facing the Sun has day, the other side has night.
- The Moon seems to change shape through the month — full moon, half moon, crescent, and new moon (these are its phases).
- Stars are very far away; they look tiny but are huge, like distant suns. People send rockets and satellites to explore space.
3. Let's understand
Look up by day and you see the bright Sun, which gives light and heat. Look up at night and you see the Moon and twinkling stars.
Why do we have day and night? The Earth spins like a top. The part of the Earth facing the Sun has day; the part turned away has night. As the Earth keeps spinning, day turns into night and back again.
Watch the Moon for a few weeks and you will see it change shape — sometimes a full round Moon, sometimes a half, sometimes a thin crescent, and sometimes not seen at all (new moon). These shapes are the Moon's phases.
The stars look tiny because they are very, very far away — they are really enormous, like our Sun. People are curious about the sky, so they build telescopes, rockets, and satellites to learn more about space.
4. New words
| Word | Meaning |
|---|---|
| rotate | to spin around (the Earth rotates) |
| phase | the shape of the Moon we see at a time |
| crescent | a thin curved shape of the Moon |
| satellite | an object that moves around a planet (the Moon is Earth's natural satellite) |
| space | the huge area beyond the Earth's sky |
5. Activity corner
Watch the sky for a week (with an elder). Write or draw:
- One thing you see in the day sky and two in the night sky
- The shape of the Moon on two different nights
- One question you have about space
6. Common mistakes
- Mistake: Thinking the Sun moves around the Earth to make day and night. Fix: Day and night happen because the Earth spins (rotates).
- Mistake: Thinking stars are small. Fix: Stars look tiny only because they are very far away; they are huge.
- Mistake: Thinking the Moon makes its own light. Fix: The Moon shines because it reflects the Sun's light.
7. Let Us Think
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What do we see in the sky by day and by night? By day, the Sun; by night, the Moon and stars.
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Why do we have day and night? Because the Earth spins (rotates); the side facing the Sun has day, the other side has night.
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What does the Sun give us? Light and heat.
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What are the changing shapes of the Moon called? The phases of the Moon.
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Why do stars look so small? Because they are very, very far away (they are really huge).
8. Answer key
- Sun by day; Moon and stars by night.
- Because the Earth spins — one side has day, the other night.
- Light and heat.
- The phases of the Moon.
- Because they are very far away.
9. Quick revision
- By day we see the Sun; by night, the Moon and stars.
- The Sun gives light and heat.
- Day and night happen because the Earth rotates.
- The Moon changes shape through phases (full, half, crescent, new).
- Stars look small because they are very far away.
Unit 5: Our Environment
This chapter is part of Unit 5: Our Environment. The two chapters in this unit are:
- Chapter 9: Different Lands, Different Lives
- Chapter 10: Our Sky
