When we look at a rainbow, it strikes us that it is not a flat two-dimensional image in the dome of the sky, but rather like a mosaic, made up of many separate pieces in three dimensions.
What phenomenon is behind all this?
First of all we need certain conditions to be met. Rainbows are quite rare , since we need to have a sunny and rainy day at the same time . Why is the rainbow formed? In the right conditions, the water droplets act like a prism, in such a way that when a ray of sunlight hits it, the light will simply pass or, it will bounce off the surface and then end up dispersing the white light into the seven visible colors that make up Every arc of the rainbow And the light is also reflected, so those colors are recovered. In short , refraction is the reason why all the colors of the sunlight end up separating when the water drop hits, and then we can see all the colors of the rainbow.
Rainbows are more than the half circle we usually see; seeing them as a half circle is an illusion caused by the lack of distance signals. Actually, they are really complete circles. Did you know? Mind you, you will never see a circular rainbow from the Earth’s surface because the horizon gets in our way. Basically, the horizon cuts the lower half of it. The geometry of the reflection is such that all the drops that reflect the light of the rainbow towards us are in a cone with the eyes at the tip. But, in the heights, as for example on board an airplane, it is possible to observe it. If we fly high enough, without any disturbance, we could see the entire rainbow in all its glory.
For each person, the view of the rainbow will be different, that is, in each position, we will see a different rainbow, because if you move a little to one side, the light will no longer come from the same drops of water, but from the that are next to it, resulting in a different rainbow. Each color has a different wavelength. For example, violet light has a much shorter wavelength than red light. The shorter the wavelength of the color, the more it changes direction. Therefore, violet light changes direction more than green light. And the yellow light changes direction more than the red light.
The circle (or semicircle) is due to a collection of droplets suspended in the atmosphere that are capable of concentrating scattered light at deviation angles of 40-42 degrees from the original path of sunlight. Thus, the range of angles at which raindrops are reflected is the real reason that rainbows are curved. These droplets actually form a circular arc, and each droplet within the arc scatters the light and reflects it back to the viewer.
Once it is clear to us that rainbows are circles, we can understand that raindrops flash the rays of the rainbow at an angle of 42 degrees from the point directly opposite the sun. Thus, all the drops that produce rainbow sparkles are on the surface of a cone with the tip in your eye.
Ready to take a different look at this phenomenon of nature?
