How Does a Rainbow Form?

Introduction

      Rainbows are really cool and fascinating to learn about! Did you know that rainbows are often used in art to symbolize a bridge between Earth and the heavens above?  Rainbows have lots of pretty colors when you look at them! 

Colors of the Rainbow

     Did you know that a rainbow has seven colors? The colors of the rainbow are red, orange, yellow, green, blue, indigo, and violet. And did you know that small raindrops make light colors like red, orange, and  yellow, and the large raindrops make colors like green, blue, indigo, and violet?

Rain and Sunlight

     A rainbow can appear because raindrops mix with light waves that can make the different colors of the rainbow. A rainbow forms when the sun shines through water droplets (raindrops) while it is raining or was recently raining.  

    A rainbow is made by water droplets and sunlight, and in the sky it can look amazing. When viewed from an airplane with the sun behind it, a rainbow may look like a complete circle. The shadow of the plane will be in the middle. 

     On Earth, a rainbow won't look like a complete circle. It will look like a multicolored arc (a part circle) or curved line in the sky. Sometimes you can see the complete arc from one side to another, but often you may only see part of the rainbow if it is blocked by thicker clouds.

    Most rainbows form when the sun rays strike the raindrops falling from rain clouds. Rainbows appear in the part of the sky that is opposite of the sun, so that the light from the sun can shine through the water droplets.

Rainbow Shapes

     A rainbow is an arc and it’s curved like a colorful partial circle. It is pretty to look at and it is a wonderful sight! Nature creates rainbows in the sky. Rainbows can be found almost anywhere in the world where it is raining. You can also form a small rainbow on a sunny summer day with the sunlight shines through water droplets from a sprinkler or hose. 

Where Should the Sun Be?

     The sun should always be behind you so the rainbow can be seen. A rainbow needs water and light, so the most common way to see a rainbow in nature is on a day when the sun is out and yet it is raining. 

     Since the sun has to shine through the rain drops, the most likely times of day to form a rainbow is when the sun is bright but in a lower position in the sky, such as early in the morning or later in the afternoon. When the sun is directly overhead around noon, it doesn't go through as many drops. It is better when the sun is more to the side.

    Rainbows can only be seen when the sun is out. This is because rainbows are created by sunlight hitting water droplets, so if it is not sunny you won't be able to see a rainbow!

Glass and Prisms 

     A prism is a glass triangle. It is shaped so that when sunlight goes through a prism, the glass bends the light so you can see the colors of a rainbow. The glass prism bends the light like the raindrops bend the light in nature. Sunlight follows a straight line when it moves through the air. When it hits the curved raindrop or glass prism, it bends the light and breaks apart the wavelengths of light into its different colors.

Rainbows in Space 

     Believe it or not, Earth is NOT the only place that has rainbows! Scientists believe that Titan, one of the moons of planet Saturn, might have rainbows, too! Titan's air contains a type of gas that could create rainbows when the sun shines.