A soap bubble usually pops because some part of it becomes too thin due to evaporation or drainage of fluid. The change in thickness also changes the color of light the bubble reflects. Why?

To understand why the change in thickness also changes the color of light the bubble reflects, we definitely know that

mλ = dsinθ

when d sin θ = mλ, we expect constructive interference

d = distance between the slits

θ = the angle relative to the incident direction

m = order of the interference

Hence, a change in the thickness will also cause a change in the wavelength, and as wavelength changes, various colors are generated.

The light's path difference is therefore generated as a result of the thickness variation of the soap bubble.

Explanation:

To understand why the change in thickness also changes the color of light the bubble reflects, we definitely know that

mλ = dsinθ

when d sin θ = mλ, we expect constructive interference

d = distance between the slits

θ = the angle relative to the incident direction

m = order of the interference

Hence, a change in the thickness will also cause a change in the wavelength, and as wavelength changes, various colors are generated.

The light's path difference is therefore generated as a result of the thickness variation of the soap bubble.