The Ray Model of Light

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The Ray Model of Light
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Part 1 Properties of Light

• Light travels in straight lines

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• Light travels VERY FAST around 300,000
  kilometres per second.

At this speed it can go around the world 8 times
in one second.
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• A luminous object like a candle radiates light
  in all directions
• We can use a light ray, which is a line and
  arrow showing the direction light is travelling,
  to show this.

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• Using Light rays to show the path of light
  striking an object is called Geometric Optics
• When light emitted from a source (the Sun)
  strikes an object (Earth), it is called Incident
  Light

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3 Classifications of Matter

• Recall
• A transparent object lets light pass through it
  easily

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3 Classifications of Matter

• Recall
• A translucent object allows some light to pass
  through

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3 Classifications of Matter

• Recall
• An opaque material does not let any light pass
  through it

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• An image is a reproduction of an original object
  that is produced through the use of light
• A mirror is any polished
• surface that exhibits
• reflection
• Reflection is simply the
• bouncing back of light
• from any surface

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Part 2 - Reflection

• Reflection from a mirror

Normal
Reflected ray
Incident ray
Angle of reflection
Angle of incidence
Mirror
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Activity

• In your lab groups, try Activity 11.5 on Page 482
  and 483

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• The Law of Reflection

Angle of incidence Angle of reflection
In other words, light gets reflected from a
surface at ____ _____ angle it hits it.
The same !!!
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Clear vs. Diffuse Reflection

• Smooth, shiny surfaces have a clear reflection

Rough, dull surfaces have a diffuse
reflection. Diffuse reflection is when light is
scattered in different directions
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Specular Reflection

• Specular reflection is the reflection of light
  off a smooth surface

Disco rules!
The water acts like a plane mirror
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Using mirrors

• Two examples

2) A car headlight
1) A periscope