The scattering of light by a body with a particle diameter (D_p) to wavelength ratio less than 0. 03 is termed Rayleigh Scattering. The wavelength of light scattered is dependent on the D_p, and the amount of light scattered is dependent on the number of particles present per unit volume. Shorter visible wavelengths, such as blue, are scattered by smaller particles than are the longer wavelengths like red. This is the reason why, during daylight, the sky is blue when looking away from the sun. See also Visible Light.