1. Reflection Objectives:
Describe how light reflects off rough and smooth surfaces.
Explain the law of reflection.

2. Reflection of Light
Light can be modeled as a _______ or as a stream of ____________.
A 3rd model of light is a light ray.
Light rays are lines drawn to trace the path of light.
The drawing of light rays is called a ray diagram.
Ray diagrams are especially useful in reflection and refraction of light.
What types of objects reflect light?
Wave; particles

3. Reflection of Light, cont.
Law of Reflection
“The angle of incidence equals the angle of reflection.”
Normal: a line perpendicular to the surface where light hits it

4. Reflection of Light, cont.
Why can you see your reflection in a store window, but not in a brick wall? What differences are there in these two surfaces?
Diffuse reflection
Reflection off rough surfaces (i.e., the wall)
Incoming parallel light waves are reflected in many directions.
Keep students brainstorming until they come up with smooth vs. rough surfaces.

5. Reflection of Light, cont.
Regular reflection
Reflection off smooth surfaces
Reflects parallel light waves in only one direction

6. Review What types of objects reflect light?
If you cannot see your reflection in an object, what type of reflection is occurring?
When you see your reflection, what type of surface are you looking into?
State the law of reflection.

7. Assignment!!  Directions to write on the back side of your worksheet:
Draw the 2 surfaces drawn on the board.
Draw a ray diagram for light rays reflecting off the 2 surfaces.
Teacher draws a rough surface and a smooth surface on the board, whit incoming light rays already drawn.