1. Light and shadows
My Pals are Here! Science © 2008 Marshall Cavendish (Singapore) Private Limited

2. Questions to think about…
How well can we see through different types of materials?
How are shadows formed?
What helps us to see?
My Pals are Here! Science © 2008 Marshall Cavendish (Singapore) Private Limited

3. What helps us to see?
Light is a form of energy that helps us see the things around us.
Things that give off light are known as sources of light.
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4. What helps us to see?
During the day, the Sun is our main source of light.
The Sun gives off its own light.
It brightens our surroundings and helps us to see the things around us.
My Pals are Here! Science © 2008 Marshall Cavendish (Singapore) Private Limited

5. What helps us to see?
At night, we use other sources of light to help us see.
My Pals are Here! Science © 2008 Marshall Cavendish (Singapore) Private Limited

6. How does light help us to see?
Although most of the things around us are not sources of light, we can still see them.
This is because these things reflect light into our eyes.
When light bounces off something, we say that light is reflected.
My Pals are Here! Science © 2008 Marshall Cavendish (Singapore) Private Limited

7. How does light help us to see?
When light bounces off from something, we say that light is reflected.
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8. How well can we see through different types of objects?
Look at the objects below.
They are made of materials such as wood, metal, some types of plastics, cardboard and clay.
Such materials do not allow light to pass through them.
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9. How well can we see through different types of objects?
Look at the objects below.
They are made of materials such as paper, some types of plastics and cloth.
Such materials only allow some light to pass through them.
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10. How well can we see through different types of objects?
Look at the objects below.
They are made of materials such as glass and some types of plastics.
These materials allow light to pass through them.
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11. How can we know how much light passes through an object or a place?
A light sensor can measure the amount of light passing through an object.
The measurements taken can be recorded in a datalogger connected to the light sensor.
The measurements can be transferred from the datalogger to a computer, and shown as a graph.
light sensor
datalogger
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12. How are shadows formed? A shadow is the dark area formed by an object.
Light travels in straight lines.
When light is completely or partially blocked by an object, a shadow of the object is formed.
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13. Shapes and sizes of shadows
The position of an object can affect the shape of its shadow.
When an object is placed at different positions, it can form shadows of different shapes.
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14. Shapes and sizes of shadows
The position of the light source can change the size of a shadow.
When the light source is closer to the object, the shadow of the object becomes bigger.
My Pals are Here! Science © 2008 Marshall Cavendish (Singapore) Private Limited

15. Shapes and sizes of shadows
The position of the light source can change the size of a shadow.
When the light source is further from the object, the shadow of the object becomes smaller.
My Pals are Here! Science © 2008 Marshall Cavendish (Singapore) Private Limited

16. My Pals are Here! Science © 2008 Marshall Cavendish (Singapore) Private Limited

17. The end
My Pals are Here! Science © 2008 Marshall Cavendish (Singapore) Private Limited