6A10.20: Diffuse vs Specular Reflection

Description: This demonstration illustrates the difference between Diffuse and Specular reflection.

Equipment: Setup Procedure:
  1. Clean the piece of glass.
  2. Place the black cloth on the table.
  3. Place the frosted sheet on one side of the light bulb, and the clear sheet of glass on the other side (see picture).
  4. Connect the light bulb to the variac and make sure it works. Leave the variac at about 100V.
Demonstration Procedure:
  1. Note the two different sheets you have in front of the light bulb.
  2. Turn on the light bulb, and dim the lights in the room.
  3. Notice that the clear sheet of glass reflects the light from the light bulb. This is an example of Specular reflection.
  4. Note that the frosted plastic does not reflect the light form the light bulb. This is an example of Diffuse reflection.
  5. When finished, turn off the variac.