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NCERT Solutions for Class 5th The World Around Us Chapter 9 Changes Around Us in a Day (Day and Night) — In-text Questions

Book page 149 Updated on2026-09-19

Q1.
What causes day and night?
Answer

Day and night happen because the Earth turns round on itself. The Earth is a huge ball. The Sun can light up only the half of it that is facing the Sun. That lit half has day. The other half is in shadow, and it has night. The Earth keeps turning, so every place moves from the lit half into the dark half and back again.

Follow one full turn, step by step:

  1. The Earth turns round on an imaginary line through its middle. That line is called its axis. This turning is called rotation.
  2. One full turn takes about 24 hours — that is one day and one night together.
  3. When your town is just coming into the light, you see the Sun at the edge of the sky. We call it sunrise.
  4. As the Earth turns further, your town comes fully into the light. It is midday.
  5. Then your town starts moving out of the light. The Sun looks lower and lower. That is sunset.
  6. Now your town is on the dark side. It is night. The Earth keeps turning, and in a few hours the Sun rises again.
Sun (or torch) stays in oneplace DAY NIGHT The Earth rotates axis One full turn = about 24 hours
Only half the Earth can face the Sun at a time. That half has day; the other half has night.
Why the Sun cannot light the whole Earth: Light travels in straight lines. It cannot bend round a ball. So the far side of the Earth is always in the Earth's own shadow. Since the Earth never stops turning, that shadow keeps moving across the world — and that moving shadow is what we call night.
Did you know? Dong village in Arunachal Pradesh is called India's ‘First Village of the Sunrise’. Because it lies furthest east in our country, it turns into the sunlight before anywhere else in India does.
Q2.
The Sun seems to be rising in the east moving across the sky and setting in the west. So, is the Sun moving?
Answer

No. The Sun is not going round the Earth. The Sun stays where it is. It is the Earth that is turning, and that turning makes the Sun look as if it is travelling across the sky.

You have felt this trick before:

  1. Sit in a moving bus or train and look out of the window.
  2. The trees and poles seem to run backwards, past you.
  3. But the trees are not moving at all. You are.
  4. In exactly the same way, the Earth turns towards the east, so the Sun appears to slide across the sky towards the west.
The bus really moves this way The trees only seem tomove this way
The trees stand still; the bus moves. The Sun stands still; the Earth moves.
What we seeWhat is really happening
The Sun rises in the eastOur part of the Earth turns into the sunlight from the east side
The Sun crosses the skyThe Earth keeps turning under the sunlight
The Sun sets in the westOur part of the Earth turns out of the sunlight on the west side
The Sun is gone all nightWe are on the shadow side of the Earth
Why it must be the Earth and not the Sun: The Sun is enormously bigger than the Earth and it is very, very far away. It is the small thing that spins, not the huge one that carries it. In Activity 1 on page 150 you can see this for yourself: the torch never moves, only the globe turns — and still, to a tiny person standing on that globe, the torch would appear to rise and set.
Words to keep: The Sun does not rise and set; it only appears to. We still use the old words sunrise and sunset because they are short and everyone understands them.
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