Page 111 - Viva ICSE Science 5 : E-book

is near the horizon, a long shadow of an object is formed. The shadow becomes shorter
during the middle of the day when the sun is overhead.

ACTIVITY TIME

To study the characteristics of shadow

You Need:
A torch, a dark room, a partner (any of your friends)

What to Do:
• Take a torch and go to a dark room with your partner.
• Ask her to stand at a distance in front of you.
• Switch on the torch and focus on her. A shadow falls
behind her.

• Notice the colour and size of the shadow.
• Ask your partner to move step-by-step towards you.
• Notice the size and colour of the shadow with each step.

You will observe that the colour of the shadow remains the same, i.e., black, but its size increases as
the distance between you and your partner decreases.
• Now ask your partner to stay at one place and change the position of the torch with respect
to her. Keep the focus of the torch on your partner.

You will observe that the position of the shadow changes as the position of the torch is changed.

Rotation and Revolution of Earth

There are two types of movements of the earth—rotation and revolution.

An imaginary line running through the centre of the earth is called its axis. The circular
movement of the earth on its axis is called rotation. It takes 24 hours to complete one
rotation. The rotation of the earth on its axis causes day and axis

night. The half that faces the sun during the rotation at a
north
particular moment has day, while the other half that is away pole

from the sun has night.

The earth moves around the sun in a fi xed path called orbit.
This movement is called revolution. The earth completes one
revolution around the sun in 365¼ days. This time period
south
makes one year on the earth. The revolution of the earth is pole
responsible for the change in seasons. Earth’s rotation

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