This weekend was pretty rainy in Manoa. At around 5 pm when I went into my living room to grab a snack I noticed that there was a rainbow across the valley. Manoa is so rainy that rainbows are, for the most part, a daily occurrence, although on most days I am not at home when the sun is up.
Anyways, rainbows are a fine example of light refraction. As everyone knows, in order for a rainbow to occur, water drops and a light source must be present. The light source must be at a lower angle in order for the rainbow to occur. The water drops refract the light, then the light is reflected off the back of the drop, and then the light is refracted yet again as it is leaving the drop. The different colors of the rainbow occur due to the different wavelengths. The raindrop acts as a prism and refracts the white light into the different colors. As this white light is refracted through the raindrop, the wavelength of each color comes into play. Red has the longest wavelength of the colors, and violet has the shortest wavelength.
Unfortunately, rainbows are incorporeal (vocab anyone?). There is no pot of gold at the end of a rainbow because rainbows are not solid. A rainbow is only visible if the viewer has their back to the light source and if there is some type of water droplets in front of the viewer.
In the picture above, the sun's light is the white light source. I am the viewer, the sun was behind me (and to my right), and it was raining on the other side of the valley.
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