1. Refraction

2. What’s this called again?
Explain what we are seeing.

3. (c) McGraw Hill Ryerson 2007
Light Can Be Refracted
When light travels from one transparent medium to another of a different density, it changes speed, and refracts
The bending of light, due to a change in speed, is called refraction.
See page 174
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4. (c) McGraw Hill Ryerson 2007
Light Can Be Refracted
Eg. Light rays entering this glass block will bend (refract) because the glass is more dense, causing the rays to slow down.
Once inside the glass the light rays move in a straight line.
What will happen when the light rays
leave the glass and move back into
air, which is less dense?
See page 174
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5. (c) McGraw Hill Ryerson 2007
Light Can Be Refracted
They will travel faster and change direction again (refract)
See page 174
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6. (c) McGraw Hill Ryerson 2007
Angle of Refraction
The angle of refraction is measured from the refracted ray to the normal.
See page 174
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7. Refraction of Light in Water
Objects in water appear in a different location than they actually are.
This is due to the refraction of the light.
See page 175
Take the Section 5.1 Quiz
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8. How do we know which way the light will bend?

9. (c) McGraw Hill Ryerson 2007
When light moves from a LESS dense medium to MORE dense, the light rays bend TOWARD the normal:
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10. (c) McGraw Hill Ryerson 2007
When light moves from MORE dense LESS dense,
rays bend AWAY from the normal:
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11. Is it the same for different gases?

12. Is it the same for different gases?
Yes

13. (c) McGraw Hill Ryerson 2007
What’s happening here?
See page 175
Take the Section 5.1 Quiz
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14. Refraction of Light in Air
Warm air is less dense than cold air.
Mirage: An illusion (misleading appearance), like the appearance of water on the road ahead on a hot day.
Reason: Air closer to the ground is warmer and therefore less dense.
Light from the sky is refracted upward as it enters the less dense air.
The “pools of water” are actually images of the sky refracted by warm air near the ground.
See page 175
Take the Section 5.1 Quiz
(c) McGraw Hill Ryerson 2007

15. Refraction of Light in Air
The “pools of water” you see on the highway on a hot day is due to the air closer to the ground is hotter and less dense than air higher up.
Light from the sky directed at the ground is bent upward as it enters the less dense air.
The “pools of water” are actually images of the sky refracted by warm air near the ground.
See page 175
Take the Section 5.1 Quiz
(c) McGraw Hill Ryerson 2007

16. Homework: Practice WS: BLM 2-17, Go over in class Remaining time:
Read pages ,
Answer Reading Check Questions #6, 7 page 175
Answer Check your Understanding p181 #6,7, 11