Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

Why does a soap bubble reflect virtually no light just before it bursts? Light d

ID: 3163545 • Letter: W

Question

Why does a soap bubble reflect virtually no light just before it bursts?

Light does not interact with a soap film.

We have total internal reflection. The light keeps on reflecting inside the bubble until the bubble bursts.

It absorbs all the light energy, so that it has enough energy to burst.

This is an example of polarization by reflection. The light becomes p-polarized, but only s-polarized light is reflected.

The reflected light from the front and back surface destructively interfere, because the path difference is nearly zero, but the phase shift upon reflection differs by 180o for the two surfaces.

a.

Light does not interact with a soap film.

b.

We have total internal reflection. The light keeps on reflecting inside the bubble until the bubble bursts.

c.

It absorbs all the light energy, so that it has enough energy to burst.

d.

This is an example of polarization by reflection. The light becomes p-polarized, but only s-polarized light is reflected.

e.

The reflected light from the front and back surface destructively interfere, because the path difference is nearly zero, but the phase shift upon reflection differs by 180o for the two surfaces.

Explanation / Answer

The colours in a soap bubble are a combination of the colours that do not undergo destructive interference and their degrees of constructive interference. Thick walls of the bubble cancel out longer wavelengths and as the walls get thinner even shorter wavelengths are cancelled. After a certain point, the bubble is too thin to create interference of visible light as all wavelengths are cancelled out and hence it appears black.

Hire Me For All Your Tutoring Needs
Integrity-first tutoring: clear explanations, guidance, and feedback.
Drop an Email at
drjack9650@gmail.com
Chat Now And Get Quote