Page 36 - Science and Technology Std 3

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Light rays from the torch pass through a hole, a glass and water.
Then, the rays pass through glass to the paper. Therefore, light
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can pass through water, glass and paper. Light cannot pass
through objects such as a book. The dark area behind the book

is called a shadow. The shadow is found behind the object that
does not allow light to pass through.

Reflection of light

Light rays can strike on a shining surface and go in a different

direction. This action is called reflection of light. A mirror is a
better light reflector than a shining plate. When you look at

yourself in the mirror, you see your image. This is because the
light rays from your face are reflected.

Any smooth and shining surface reflects light and forms an

image. When you look into water, your image will appear. This
is because the water surface is smooth and can reflect light.
Objects which are neither smooth nor shiny do not reflect light.

Examples of these are pieces of paper, board and soil.

Therefore, the general characteristics of light are as follows.

1. Light travels in a straight line.

2. Light is reflected when it strikes on a smooth or shiny

surface.

3. Light bends when it passes from one medium to another.

This bending of light is called refraction. For example, when

you take a ruler and hold it in the air, it looks straight. But
when you put it in water it looks bent.

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PROPERTY OF UNITED REPUBLIC OF TANZANIA GOVERNMENT
Ministry of Education, Science and Technology
Science and Technology 3.indd 29 03/08/2019 11:02