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How rainbows are formed
Transcript of How rainbows are formed
What is a Rainbow?
A rainbow is an arc of light, separated into bands of colour, when the sun's light is refracted and reflected by water droplets.The colours of the rainbow are red,orange, yellow,green, blue, indigo, and violet
To Understand how rainbows are formed, we must first look at light.White visible light is made up of a continuous sequence of colours, known as the visible spectrum. The colours of the visible spectrum are red,orange,yellow,green,blue,indigo, and violet. These visible spectrum have different electromagnetic spectrum, which is the amount of energy an electromagnetic wave has. Red, being the least energetic in the visible spectrum, and violet, being the most energetic.
We don't see rainbows everywhere because in a vacuum, all these visible spectrum are traveling at the same speed(the speed of light). Sir Isaac Newton, a famous Mathematician, discovered that in a triangular prism, the speed of light slows down. Since red light is the least energetic, it is slowed down the least, while violet is the most energetic, so it is slowed down the most. This is called dispersion.
How Are Rainbows Formed?
For a rainbow to form, the three steps stated below must be completed:
1. The sun's light must hit the water droplets in the air.
2. Dispersion takes place, and
3. Total internal refraction takes place and the spectrum meets our eyes
Our brain extend these light rays backwards to form a virtual image: an arc of spectrum
Why Don't We See Rainbows Everywhere?
Other Places You May See Spectrum
Astronomers and Spectrum
Astronomers use the visible spectrum to gather information from stars. One way by doing this was by looking at the stars' shift in colours, and by seeing a shift to red light, it meant that the stars were moving away from us, and with the shift to blue, it meant the stars were coming closer to us. Another way of doing this is using the colour that the star emits and the wavelength of of the spectrum, to identify what chemicals are on other stars. To check this, they use a spectrometer, which is a tool used for reading the wavelengths of the spectrum by intensity of the colours.
What are the seven colours of the visible spectrum?
I hope you've been listening because its time for...
Red, Orange, Yellow, Green, Blue,Indigo,Violet
What are the three steps to forming a rainbow?
What is the angle normally between the red (top area of the rainbow) to the original incident ray?
Thanks for Listening!