"Natural Science 4" is an interactive encyclopedia that includes scientific information in the understanding of fourth grade students, wonderfully illustrated and animated.
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* Chapter 5 Lesson 27 *
* The rainbow. The colors *
Sometimes, after rain, we can see a multicolored arc in the sky, the ends of which seem to touch the Earth. This is called a rainbow and is considered one of the most beautiful natural phenomena. All over the world, the rainbow is associated with tranquility, peace and understanding between people.
From a physical point of view, the rainbow is an optical and meteorological phenomenon. It is manifested by the appearance of a spectrum in the form of a colored arc in the sky when sunlight passes through water droplets in the atmosphere. Most often the rainbow is observed after rain, when the sun is close to the horizon. This is what happens when a ray of light enters a glass prism! (to be illustrated) The same happens when white sunlight enters a drop of water. When the light comes out, the color separation is amplified.
The rainbow appears in the opposite part of the sky from the sun. To see it, you have to stand with your back to the sun. When it is far above the horizon, the rainbow cannot be seen.
Also, we can only see it if we are between the Sun and the water droplets. In fact, if the position of the Sun is low enough in the sky, and we are in a high place, such as the top of a mountain or in an airplane, we can see a circular rainbow.
From outside to inside, the colors of the rainbow are: red, orange, yellow, green, blue, indigo and violet.
Light waves have different lengths, some being longer than others. Different colors are determined by the wavelength of light. Humans can only see a small fraction of the colors of light. They make up the visible spectrum. Basically, less than 1% of light is visible to the human eye. Ultraviolet or infrared light, for example, is not perceived by human eyes.
You can also break down the light beam into the colors of the rainbow through a very simple experiment. This should take place in a completely dark room. Place a mirror in a glass of water, then illuminate the mirror with a flashlight. Hold a sheet of white paper over the glass at some distance from it. You will be able to observe a rainbow, with its seven colors, right in your room.
The brightest and most common of the rainbows is called the main rainbow. Sometimes a second, less bright rainbow forms outside of it, doubling it. This is a secondary rainbow.
Rainbows can also occur near waterfalls or artesian fountains, and the effect can be created artificially by dispersing water droplets in the air on a bright day.
How else can you create a rainbow?