NATS 1870 Lecture Notes - Lecture 17: Soot, Reflection Nebula, Titanium Dioxide
20 Jun 2016
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Document Summary
Colour that results from the physical nature of the material that a light beam interacts with. Usually the material has a size similar to the wavelength of visible lights. Scattering anything that is white, is white because of scattering. A process where the direction of light is changed by small particles. > colour determined by relationship between specific wavelength and size of the particle. Rayleigh scattering: smallest particle size particle size < wavelength. Easier to scatter/re-direct short wavelengths than the long wavelengths. > rayleigh scattering: white light arrives from sun at top of our atmosphere, blue wavelengths are scattered in different directions by molecules made of 2 atoms (n 2 , o2 , Oh: we see the re-directed blue wavelengths as the diffuse blue sky. When we look at the sun (but don"t actually look at the sun) about 4 % of the blue light has been removed by these interactions in the atmosphere.
