Page 98 - Viva ICSE Science 4 : E-book

TIME TO REVISE

Write (T) for true and (F) for false statements.
1. Light travels in a curved line.
2. Butter paper is an opaque material.

3. Light travels in all directions from its source.

Formation of Shadows

We have already learnt in this chapter that light always
travels in a straight line. Whenever an object comes

in the path of light and blocks it, a dark shape called
shadow is formed on the surface at the other side of the

object. The object must be either opaque or translucent
to form a shadow. Opaque objects form dark shadows
on the surface while translucent objects form faint

shadows. Transparent objects do not form shadows as
they allow light to pass through them completely. Formation of shadow

A shadow always appears black or dark, as it does not depend on the colour of the
object. It is always formed on the surface opposite to the source of light and may be

bigger or smaller than the object.

The length of a shadow is diff erent at diff erent times of the day. It changes with change
in the position of the sun. Shadows are long in the morning and evening while they are
the shortest at midday when the sun shines overhead.

morning midday evening

Shadows at diff erent times of the day

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