Translations:Adventist Youth Honors Answer Book/Health and Science/Optics/28/en

2. Explain how light behaves when it strikes or traverses water, oil, feldspar, and a mirror.

Water

When light travels though air and strikes water it is bent or refracted. This is caused by the difference between the speed of light through air and the speed of light through water.

Oil

When light strikes oil (or a soap bubble) it gets reflected twice. The first reflection occurs when light strikes the top surface of the oil, but not all of the light is reflected here. Some of the light penetrates the surface of the oil and is reflected from the bottom surface. This causes the light to undergo a phase shift. When the light emerges from the oil and is recombined with light reflected from the surface, some of the light frequencies are canceled because of the phase shift, and others are reinforced. Which frequencies are canceled and which are reinforced depends on the angle at which they are viewed, and the viewing angle changes continuously over the surface of the oil. The effect is that one band of oil will appear yellow, another green, another yellow, etc. This is why you see a rainbow in a puddle of oil or on a soap bubble.