We have all seen it before. The beautiful shifting color of iridescent objects. To those who haven't seen it, do the dishes for once and look at the soap bubbles. I feel sorry for your mother. In any case, what causes it? Is it magical? Like unicorns, which actually aren't magical, they just evolved into narwhals. It is in fact a quite complicated process that even after reading several peer reviewed Wikipedia articles, I am still a bit confused. However, the basics of iridescence is quite simple.
For those of you who are in a hurry, I will explain the gist of iridescence quickly. Two thin films, very thinly separated on the iridescent surface reflect the light back, but slightly differently than each other, due to their difference in distance and reflection qualities, thereby making different colors depending on which angle you look at them. This is seen better in the fly above than the peacock feathers below.
If you didn't quite follow that, or just want more details, or are simply bored and don't think that you have anything better to do with your life, then read on. Anyone who has taken physics learns that color is made by light interacting with something that changes it. By absorbing some light and reflecting others, pigments like the melanin in your skin create a brownish look, or change the angle/wavelength of the light, such as in a rainbow. These two types of color are known as pigment and structural coloration. Interestingly enough, both these qualities are seen in peacock feathers; as melanin gives the brownish color and structural coloration does the rest. Structural coloration is what causes iridescence. The light comes into the first film, some is reflected back, while other light continues on through to the second layer (by the way there can be more than two layers) and then is reflected back differently than the first. The two ways that this happens is by phase shift and interference. These are the two things that I have trouble understanding and do not feel like I should be tainting minds with poor understanding. If you can comprehend those things, feel free to fill the rest in. Also, if I have something wrong in this article, please also tell me. I am trying to learn by doing this too, while pointing to the glory of God.
If you didn't quite follow that, or just want more details, or are simply bored and don't think that you have anything better to do with your life, then read on. Anyone who has taken physics learns that color is made by light interacting with something that changes it. By absorbing some light and reflecting others, pigments like the melanin in your skin create a brownish look, or change the angle/wavelength of the light, such as in a rainbow. These two types of color are known as pigment and structural coloration. Interestingly enough, both these qualities are seen in peacock feathers; as melanin gives the brownish color and structural coloration does the rest. Structural coloration is what causes iridescence. The light comes into the first film, some is reflected back, while other light continues on through to the second layer (by the way there can be more than two layers) and then is reflected back differently than the first. The two ways that this happens is by phase shift and interference. These are the two things that I have trouble understanding and do not feel like I should be tainting minds with poor understanding. If you can comprehend those things, feel free to fill the rest in. Also, if I have something wrong in this article, please also tell me. I am trying to learn by doing this too, while pointing to the glory of God.
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