  An experiment is described that enables students to understand the properties
of atmospheric extinction due to Rayleigh scattering. The experiment requires
the use of red, green and blue lasers attached to a travelling microscope or
similar device. The laser beams are passed through an artificial atmosphere,
made from milky water, at varying depths, before impinging on either a light
meter or a photodiode integral to a Picotech Dr. DAQ ADC. A plot of measured
spectral intensity verses depth reveals the contribution Rayleigh scattering
has to the extinction coefficient. For the experiment with the light meter, the
extinction coefficients for red, green and blue light in the milky sample of
water were 0.27, 0.36 and 0.47 cm^-1 respectively and 0.032, 0.037 and 0.092
cm^-1 for the Picotech Dr. DAQ ADC.
