Bellwork (4/29)

• What is light scattering?

• The deflection of a light ray from a straight path

Light Scattering

• Why is the sky blue and sunset red?

Rayleigh Scattering

• Polarizes the sky!

Law of Reflection

4/29/14

Law of Reflection• Law of Reflection: The angle of incidence

equals the angle of reflection• Incident Ray: the light ray that hits the

surface• Reflected Ray – the light ray that bounces off

the surface• Angle of Incidence: the angle between the

incident ray and the line perpendicular• Angle of Reflection: the angle between the

reflected ray and the line perpendicular

Law of Reflection

Bellwork (4/30)

• What is the Law of Reflection?

• The angle of incidence equals the angle of reflection

Calendar

• Today (4/30): Law of Refection Assignment

• Tomorrow (5/1): Refraction notes

• Friday (5/2): Reflection Practicum

• Monday (5/5): Pre-Lab

• Tues. (5/6): Lab

• Sometime: Pop Quiz

Law of Reflection

4/30/14

Law of Reflection

Mathematically:

Where,

θ = Angle of Incidence

ϕ = Angle of Reflection

θ = ϕ

Law of Reflection• Law of reflection labels:

- “Mirror” [solid line with hash marks “⁄ ⁄ ⁄ ⁄ ⁄”]

- “Perpendicular (normal) line” [dashed]

- Angle of incidence in degrees “θ = x°”

- Angle of reflection in degrees “ϕ = y°”

- Incident ray and reflective ray indicated by a solid line with arrows (rays can cross)

• NOTE: Line perpendicular, incident ray and reflected ray have to form a point (vertex)

Assignment: (due Fri 5/2/14)Design a “mirror maze” that uses at least ten plane

mirrors. You can add a creative theme or design.

1) Draw the incident ray (rays can intersect)

2) Draw the mirror line with hashes

3) Draw the line perpendicular (90°)

4) Measure the angle of incidence (θ) and include on drawing

5) Measure the angle of reflection (ϕ) and include on drawing

6) Draw the reflective ray

7) Repeat until you have a least ten