Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Dumb light question.

  1. Oct 8, 2007 #1
    If white reflects all wavelengths, why can you not see your reflection on a peice of notebook paper?

    Is it because the light is scattered or "broken up" before being reflected?
  2. jcsd
  3. Oct 8, 2007 #2


    Staff: Mentor

    That is correct, it is a diffuse rather than a specular reflection. A mirror needs to have a specular reflection more than it needs to be colorless.
  4. Oct 8, 2007 #3
    If the reflected light is diffused due to the uneven surface of the paper, I should be seeing some random image made from some random points from the surrounding ojects, right? But, instead of that, why am I seeing the paper itself?
  5. Oct 9, 2007 #4
    Like when you look at a shattered mirror, right? Except what if you kept smashing it down further (until the individual shards were the size of, say, a paper fibre) wouldn't you expect it to just look like a white powder (unless you used a microscope)?
  6. Oct 9, 2007 #5
    Magnify a paper fiber and you may see a distorted and diffracted image of someone with a microscope. Longer wavelengths (e. g, infrared) - those greater than the size of the fibers, but considerably shorter than the scale of the paper itself - may reflect a more coherent image.

    Take a sheet of paper and speak firmly toward it (not to scold!) While you are talking, bend the edges of the paper toward you until your voice is reinforced. The true sound wave "image" of you voice, analogous to light but of vastly different frequency, is being projected back at you by the paper.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook