The Miracle of Color
While soap
bubbles are miniature marvels of physics, their colors
are equally fascinating due to an iridescent quality
that results in a change of color over their limited
lifetime. This is due to how light is reflected from
both the inside and outside surfaces of the bubble.
The surface of a bubble is constantly changing
thickness due to drainage or evaporation, resulting in
change of light reflection. As the light hits surfaces
of the bubble, some of it is reflected off of the
outer surface of the bubble, resulting in changes in
color. A fraction of the light passes through the
outer layer, reflecting off the water layer or the
inner layer of soap. The visible color is dependent on
the interference between the two rays of light.
Constructive interference creates brighter
colors while destructive interference results in
dimmer colors. As the bubble get thinner and thinner,
more and more destructive interference is exhibited
which is why, the precise moment before the bubble
pops, it appears to be black.
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