Page 109 - Viva ICSE Science 5 : E-book

Objects that do not allow light to pass through them are called
opaque objects. Such objects refl ect the light and so we cannot see
through them. For example, wood, brick wall and book are opaque
objects.
Book (opaque)

There are some other objects that allow only some light to
pass through them. A blurred picture is seen when we look
through these objects. Such objects that allow only partial

light to pass through them are called translucent objects.
Butter paper, smoked glass and coloured glass are some
examples of translucent objects. Coloured glass (translucent)

TIME TO REVISE

Fill in the blanks.
1. To view things, you need a source of __________.
2. Objects which emit light of their own are called __________ objects.

3. Glass, air and water are __________ objects.
4. Smoked glass and coloured glass are some examples of __________ objects.

ACTIVITY TIME

To classify objects as transparent, translucent and opaque
You Need:
Objects like chalk, eraser, pencil box, paper, handkerchief, school bag, glass tumbler, plastic
scale, a glass slide and a candle
What to Do:
• One by one pick each of the objects and hold it in between your view and the candle.
• Observe whether or not you are able to see the fl ame through diff erent objects.
In this way, you can categorise objects into transparent, translucent and opaque.

Discuss your results in class.

Shadow

We know that when light falls on an opaque object it gets
refl ected. This creates a dark image on the surface at the other

side of the object. This dark image is called the shadow of
the object. Similarly, when sunlight falls on our body it gets
refl ected and our shadow is formed on the opposite side of
the light. The formation of a shadow is a natural phenomenon.
Shadow of a boy

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