making rainbows
By zteve t evans
Everyone is familiar with rainbows. That multicolored band of light arching over the sky on a rainy day is one of the most amazing spectacles in nature bringing cheer and wonder to the admiring beholder.
Making rainbows
Rainbows are created by light reflecting in water droplets in the air which causes a spectrum of light to appear as a multicolored arch in the sky. The water droplets are usually falling as rain but a rainbow can be formed in a fountain, a waterfall and sometimes in fog. A rainbow appears to the observer when the sun is behind them and shining onto rain or water droplets in front of them. The sun must be behind the observer and the water drops in front.
Although sunlight appears white when it is broken it appears in a spectrum of colors. When light hits the water droplets it is reflected back at different angles and white light is broken into the many colors of the rainbow which spread out forming the multicolored arch we are familiar with.
Rainbows are circular in shape and the center point is called the anti-solar point. The anti-solar point is at the end of a line that comes from the sun and passes through the head of the observer. The reason we see a rainbow as an arch instead of a full circle is because the part of the circle we do not see is below the horizon. The part of the circle we see depends upon how high the sun is positioned in the sky. The higher the sun then less of the rainbow is visible and the the arch may only just show over the horizon.
But if the observer is standing on a mountain top or in an aircraft then the full circle may be visible.
Rainbows are created by light reflecting in water droplets in the air which causes a spectrum of light to appear as a multicolored arch in the sky. The water droplets are usually falling as rain but a rainbow can be formed in a fountain, a waterfall and sometimes in fog. A rainbow appears to the observer when the sun is behind them and shining onto rain or water droplets in front of them. The sun must be behind the observer and the water drops in front.
Although sunlight appears white when it is broken it appears in a spectrum of colors. When light hits the water droplets it is reflected back at different angles and white light is broken into the many colors of the rainbow which spread out forming the multicolored arch we are familiar with.
Rainbows are circular in shape and the center point is called the anti-solar point. The anti-solar point is at the end of a line that comes from the sun and passes through the head of the observer. The reason we see a rainbow as an arch instead of a full circle is because the part of the circle we do not see is below the horizon. The part of the circle we see depends upon how high the sun is positioned in the sky. The higher the sun then less of the rainbow is visible and the the arch may only just show over the horizon.
But if the observer is standing on a mountain top or in an aircraft then the full circle may be visible.
Making double rainbows
There are times when it is possible to see a second rainbow arching over the top of the primary rainbow. This phenomenon occurs when sun rays are reflected inside the rain drops twice. This is called a secondary rainbow. The careful observer will see that the color bands in the secondary rainbow are in the opposite order to those in the primary rainbow. Because light spreads over a greater area of the sky the secondary rainbow is fainter than the primary. The area of sky between the two rainbows is called Alexander's Band and was named after Alexander of Aphrodisias who was the first known person to describe the phenomena in 200 AD.
Making moonbows
Rainbows can on rare occasions be seen at night and are known as moonbows. As the name suggests moonbows occur when light from the moon is reflected in water droplets. For this to happen the moon has to be shining strongly but even then because moonlight is not as strong as sunlight they are much fainter than day time rainbows. It can be difficult to make out the colors with the human eye but they can be captured by taking a photograph using a long exposure.
Upside down rainbows
An upside down rainbows, despite their name, are not really rainbows but halos created by ice crystals high up in the sky. Sometimes they appear as a halo around the sun.
Finding treasure
On rainy days they remind us that while nature can at times be grim and forbidding it can also be be spectacular and beautiful. They bring hope for better weather and that something better is on its way and just perhaps we will find the treasure at the end of the rainbow.
© 23/08/2015 zteve t evans
There are times when it is possible to see a second rainbow arching over the top of the primary rainbow. This phenomenon occurs when sun rays are reflected inside the rain drops twice. This is called a secondary rainbow. The careful observer will see that the color bands in the secondary rainbow are in the opposite order to those in the primary rainbow. Because light spreads over a greater area of the sky the secondary rainbow is fainter than the primary. The area of sky between the two rainbows is called Alexander's Band and was named after Alexander of Aphrodisias who was the first known person to describe the phenomena in 200 AD.
Making moonbows
Rainbows can on rare occasions be seen at night and are known as moonbows. As the name suggests moonbows occur when light from the moon is reflected in water droplets. For this to happen the moon has to be shining strongly but even then because moonlight is not as strong as sunlight they are much fainter than day time rainbows. It can be difficult to make out the colors with the human eye but they can be captured by taking a photograph using a long exposure.
Upside down rainbows
An upside down rainbows, despite their name, are not really rainbows but halos created by ice crystals high up in the sky. Sometimes they appear as a halo around the sun.
Finding treasure
On rainy days they remind us that while nature can at times be grim and forbidding it can also be be spectacular and beautiful. They bring hope for better weather and that something better is on its way and just perhaps we will find the treasure at the end of the rainbow.
© 23/08/2015 zteve t evans
References and Attributions
Copyright August 23rd, 2015 zteve t evans
Copyright August 23rd, 2015 zteve t evans