The visible Light Spectrum Colors and Wavelengths
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What does all this have to do with the colors of bubbles?
Light waves, like water waves, can interfere with each other. A bubble film is a sort of sandwich: a layer of soap molecules, a filling of water molecules, and then another layer of soap molecules. When light waves reflecting from one layer of soap molecules meet up with light waves reflecting from the second layer of soap molecules, the two sets of waves interfere. Some waves add together, making certain frequencies or colors of light brighter. Other waves cancel each other, removing a frequency or color from the mixture. The colors that you see are what's left after the light waves interfere. They're called interference colors.
The interference colors depend on how far the light waves have to travel before they meet up again--and that depends on the distance between the layers or the thickness of the soap film. Each color corresponds to a certain thickness of the soap film. By causing the liquid bubble film to flow and change in thickness, a puff of wind makes the bubble colors swirl and change.
The very thinnest film—one that's only a few millionths of an inch thick—looks black because all the reflecting wavelengths of light cancel. When the soap film looks black, it's just about to pop.
Light waves, like water waves, can interfere with each other. A bubble film is a sort of sandwich: a layer of soap molecules, a filling of water molecules, and then another layer of soap molecules. When light waves reflecting from one layer of soap molecules meet up with light waves reflecting from the second layer of soap molecules, the two sets of waves interfere. Some waves add together, making certain frequencies or colors of light brighter. Other waves cancel each other, removing a frequency or color from the mixture. The colors that you see are what's left after the light waves interfere. They're called interference colors.
The interference colors depend on how far the light waves have to travel before they meet up again--and that depends on the distance between the layers or the thickness of the soap film. Each color corresponds to a certain thickness of the soap film. By causing the liquid bubble film to flow and change in thickness, a puff of wind makes the bubble colors swirl and change.
The very thinnest film—one that's only a few millionths of an inch thick—looks black because all the reflecting wavelengths of light cancel. When the soap film looks black, it's just about to pop.
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CONSTRUCTIVE INTERFERENCE: if two waves combine, the waves can meet each other crest-to-crest, adding up and reinforcing the effect of each other,
DESTRUCTIVE INTERFERENCE: If two waves meet crest-to-trough, cancelling each other out, then they have no effect. When they meet crest-to-trough, for every "up" vibration in one wave, there is a corresponding "down" vibration in the other wave. This combination of equal ups and downs causes complete cancellation or interference.
SCIENCE OF ART IN OBJECTS AND LIVING THINGS IN THE NATURE...
WHAT CAUSES the pearly luster of an abalone shell, the beautiful colors in some bird feathers and insect wings, and the flowing patches of color in an oil slick on the street after a rain shower - and for the color of bubbles?
INTERFERENCE: where science and art meets
WHAT CAUSES the pearly luster of an abalone shell, the beautiful colors in some bird feathers and insect wings, and the flowing patches of color in an oil slick on the street after a rain shower - and for the color of bubbles?
INTERFERENCE: where science and art meets
![Picture](/uploads/4/8/1/2/4812666/4521010_orig.gif)
If the crests of two or more waves are in step (yellow and magenta waves top), or almost in step, they can combine into a larger or more intense effect (red wave top.) by means of "constructive interference."
If the crest of one wave meets the valley of another (yellow and magenta waves bottom), they cancel each other out (red wave bottom.) When two light waves cancel each other, the result is darkness by means of "destructive interference."
If the crest of one wave meets the valley of another (yellow and magenta waves bottom), they cancel each other out (red wave bottom.) When two light waves cancel each other, the result is darkness by means of "destructive interference."
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If we were to look at a highly magnified portion of a soap bubble membrane, we would notice that light reflects off both the front (outside) and rear (inside) surfaces of the bubble, but the ray of light that reflects off the inside surface travels a longer distance than the ray which reflects from the outside surface.
When the rays recombine they can get "out of step" with each other and interfere. Given a certain thickness of the bubble wall, a certain wavelength will be cancelled and its complementary color will be seen.
Long wavelengths (red) need a thicker bubble wall to get out of step than short wavelengths (violet). When red is cancelled, it leaves a blue-green reflection.
As the bubble thins, yellow is cancelled out, leaving blue; then green is cancelled, leaving magenta; and finally blue is cancelled, leaving yellow.
Eventually the bubble becomes so thin that cancellation occurs for all wavelengths and the bubble appears black against a black background.
When the rays recombine they can get "out of step" with each other and interfere. Given a certain thickness of the bubble wall, a certain wavelength will be cancelled and its complementary color will be seen.
Long wavelengths (red) need a thicker bubble wall to get out of step than short wavelengths (violet). When red is cancelled, it leaves a blue-green reflection.
As the bubble thins, yellow is cancelled out, leaving blue; then green is cancelled, leaving magenta; and finally blue is cancelled, leaving yellow.
Eventually the bubble becomes so thin that cancellation occurs for all wavelengths and the bubble appears black against a black background.
Spectra Produced by Interference
Have you ever noticed the rainbow of colors that is produced by a few drops of oil or gasoline on the surface of a puddle or on the surface of a soap bubble?These rainbows are a result of light being reflected back to your eye from the inside and outside surfaces of the oil film (or soap film). The light beam to your eye is experiencing interference. One colour's intensity is amplified, all other colors are suppressed.
You observe different colours because the thickness of the film is not uniform. Strong constructive interference occurs at only one "favoured" wavelength and this "favoured" wavelength gradually changes as the thickness of the film changes. All other wavelengths are suppressed by destructive wave interference.
As a result we see a rainbow of colors across the surface of the oil film. The same effect is seen in soap bubbles.
Have you ever noticed the rainbow of colors that is produced by a few drops of oil or gasoline on the surface of a puddle or on the surface of a soap bubble?These rainbows are a result of light being reflected back to your eye from the inside and outside surfaces of the oil film (or soap film). The light beam to your eye is experiencing interference. One colour's intensity is amplified, all other colors are suppressed.
You observe different colours because the thickness of the film is not uniform. Strong constructive interference occurs at only one "favoured" wavelength and this "favoured" wavelength gradually changes as the thickness of the film changes. All other wavelengths are suppressed by destructive wave interference.
As a result we see a rainbow of colors across the surface of the oil film. The same effect is seen in soap bubbles.
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TRANSITION INTO ART: the complementary colors
White light is made up of all colors, wavelengths between about 400 to 700 nanometers.
If one of these colors is subtracted from white light (by interference, for instance) we see the complementary color. For example, if blue light is subtracted from white light, we see yellow. The skin of a bubble glistens with the complementary colors produced by interference.