Would you see the same thin film interference pattern in a film of soap surrounded by air and a film of soap on glass? Why or why not?
Yes, you would see a similar thin film interference pattern in both a film of soap surrounded by air and a film of soap on glass. However, the specific interference pattern might have slight differences due to the refractive indices of the substances involved.
To understand why, let's first discuss thin film interference. Thin film interference occurs when light waves reflect off the upper and lower surfaces of a thin film. When the thickness of the film is on the order of the wavelength of light, interference occurs and creates a visible pattern of bright and dark fringes.
In the case of a film of soap surrounded by air, the soap film acts as a thin layer of varying thickness. As light waves strike the upper surface of the film, some of the light is transmitted through, while the rest is reflected. The reflected wave then interacts with the transmitted wave upon reaching the lower surface of the film. This interaction gives rise to interference, resulting in the observed pattern.
Similarly, in the case of a film of soap on glass, the glass acts as a substrate, and the soap film forms on its surface. The light waves strike the upper surface of the film, and some are transmitted through while others undergo reflection. The interface between the soap film and glass might have a different refractive index compared to the soap-air interface. These differences in refractive index can slightly alter the interference pattern, but the general concept and appearance of the pattern should still be present.
In summary, both a film of soap surrounded by air and a film of soap on glass will exhibit a thin film interference pattern. While there might be slight variations due to differences in refractive indices, the underlying principles and overall appearance of the pattern should be similar in both cases.