why do soap and petrol give out the seven colours when they are exposed in sunlight

Question

why do soap and petrol  give out the seven colours when they are exposed in sunlight

anonymous · Answer

due to refraction

anonymous · Answer

chromatic dispersion takes place

anonymous · Answer

but does it depend on the materialistic properties

anonymous · Answer

yes

anonymous · Answer

its due to dispersion of light.. white light has 7 colours say VIBGYOR.. when white light passes through petrol or soap, different colours get dispersed.. since each colour has its own wavelength n phase velocity, it gets disperse at different angles.. so we can see different colours

anonymous · Answer

This wikipedia article [ http://en.wikipedia.org/wiki/Soap_bubble#Interference_and_reflection ] says that it is due to interference - not refraction and dispersion.