Why does a rainbow appear?

Posted on Jan 19, 2021      144


In ancient times, because of a lack of knowledge, people explained the wonders and beauties of nature through myths and fairy tales. Back then, people had no opportunity to explore the scientific basis for why it rained, hailed, or thundered. Similarly, people described everything unknown and distant, the appearance of the rainbow in the sky is no exception. In ancient India the rainbow was the bow of the thunder god Indra. In ancient Greece there was the virgin goddess Iris with a rainbow robe. To properly answer a child how a rainbow arises, you should first understand the question yourself.

Scientific explanation of the rainbow

Most often, the phenomenon occurs during a small fine rainfall or immediately after it ends. After it, tiny clots of fog remain in the sky. It is when the clouds disperse and the sun comes out, everyone can observe with their own eyes a rainbow. If it occurs when it rains, then the colored arc is composed of tiny water droplets of different sizes. Under the influence of the refraction of light, many small water particles form this phenomenon. If you observe the rainbow from a bird's-eye view, it is not the arc that is colored, but the whole circle.

In physics, there is such a thing as the “dispersion of light”, the name given to it by Newton. The dispersion of light is a phenomenon in which there is a decomposition of light into a spectrum. Thanks to him, the usual white stream of light is decomposed into several colors perceived by the human eye:

  • red;
  • orange;
  • yellow;
  • green;
  • blue;
  • blue;
  • purple.

In the understanding of human vision, the colors of the rainbow always have seven colors and they arrange each of them in a certain sequence. However, the colors of the rainbow are continuous, they are smoothly connected to each other, so it has many more shades than we can see.

The conditions for a rainbow

To see a rainbow outdoors, they must meet two fundamental conditions:

  • The rainbow appears more often if the sun is low above the horizon (sunset or sunrise);
  • One must stand with one’s back to the sun and face the passing rain.

The multicolored arc appears not only after or during rain but also:

  • watering the vegetable garden with a hose;
  • while bathing in water;
  • in the mountains at a waterfall;
  • in a city fountain in a park.

If they reflect the rays of light from a drop of several times, a person can see a double rainbow. It is noticeable much less common, the second rainbow is much worse than the first and its color goes in a mirror reflection, tie, ends in purple.

How to make a rainbow by yourself

To make a rainbow yourself a person will need:

  • A bowl of water;
  • a white sheet of cardboard;
  • a small mirror.

They conduct the experiment in sunny weather. To do this, they lower a mirror into an ordinary bowl of water. The bowl is placed so that the sunlight falling on the mirror is reflected on the sheet of cardboard. For this purpose it is necessary to change the angle of inclination of the objects for some time. After catching the tilt, you can enjoy the rainbow.

The fastest way to make a rainbow yourself is to use an old CD. Change the angle of the disk in direct sunlight and you will get a clear bright rainbow.