The simplest way of showing dispersion is to refract a narrow beam of sunlight through a prism of glass or prismatic vessel containing water or other clear liquid.
He argued that the different humours of the human eye so refract rays of light as to produce an image on the retina which is free from colour, and he reasonably argued that it might be possible to produce a like result by combining lenses composed of different refracting media.'
refract the light to give the halo effect.
The clouds contain ice crystals which refract the light to give the halo effect.
refract upwards into Jupiter's stratosphere where they might be imaged by infrared detectors on Earth.