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.