What is the relationship between the angle in and the angle out for light on a mirror?

Consensus:
The angle of incidence = the angle of reflection
New Terms:
Normal – the imaginary line perpendicular to the mirror.
Angle of incidence – angle between the light beam and the normal.
Angle of reflection – angle between the reflected beam and the normal.

Reflection
When waves bounce off a surface.
When light bounces off an opaque object.
Two types of reflection:
Regular Diffuse

Reflection
Regular reflection
Diffuse reflection

Reflection
Anatomy of a ray
Law of Reflection
The angle of incidence equals the angle of reflection

Law of Reflection
For plane mirrors: object distance = image distance

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ABE BEV CIS DON EVA FLO GUY HAN
Abe can see: Eva, Flo, Guy and Han

Law of Reflection
ABE BEV CIS DON EVA FLO GUY HAN
Bev can see: Don, Eva, Flo, Guy and Han

Law of Reflection
ABE BEV CIS DON EVA FLO GUY HAN
Cis can see: Himself, Don Eva, Flo, Guy and Han

Law of Reflection
ABE BEV CIS DON EVA FLO GUY HAN
Don can see: Bev, Cis, Himself, Eva, Flo, Guy and Han

Law of Reflection
ABE BEV CIS DON EVA FLO GUY HAN
Eva can see: Abe, Bev, Cis, Don and Herself

Law of Reflection
ABE BEV CIS DON EVA FLO GUY HAN
Flo can see Abe, Bev, Cis, Don and Eva

Law of Reflection
ABE BEV CIS DON EVA FLO GUY HAN
Guy can see: Abe, Bev, Cis and Don

Law of Reflection
ABE BEV CIS DON EVA FLO GUY HAN
Han can see: Abe, Bev, and Cis

Law of Reflection

Law of Reflection

What is the relationship between the angle in and the angle out of light through a transparent solid?

Consensus:
As light travels into an optically dense object, it bends toward the normal.
New Terms:
Refraction – the change of direction of light as it passes through a substance.

Refraction
When light passes through a transparent material.
In a vacuum, light travels at 3 X 10 8 m/s, but since it is a wave, it travels at different speeds through different media.
Unlike sound, the more dense an object, the slower light travels.

Refraction
Because light slows down it is bent in a different direction. This is refraction.

Refraction

Law of Refraction
As light travels from a less dense medium into a more dense medium, the angle gets closer to the normal
As light travels from a more dense medium into a less dense medium, the angle gets farther away from the normal.

Law of Refraction

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Atmospheric Refraction
On very hot days, the air near the ground is warmer than the air above it. Since particles in warmer air are farther apart, light travels faster, causing refraction.

Atmospheric Refraction
You can actually see the sun after it has dropped below the horizon for several minutes because the light is refracted by the earth’s atmosphere.
The same thing occurs at sunrise.

Atmospheric Refraction

Rainbows
Occur when light from the sun is dispersed by water droplets in clouds, or falling rain drops.

Rainbows
Rainbows are actually circles. You can clearly tell from above. We would see them as circles as well, except that the ground gets in the way!

Total Internal Reflection
Occurs when light rays are at such an angle to the boundary between two different media that it “can’t escape” and is instead reflected.

Total Internal Reflection

Total Internal Reflection

Total Internal Reflection
This is the science that led to fiber optics .

Law of Refraction

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