Make your own rainbow.
As the weather warms up in time for spring and summer, chances are you'll be seeing more rainbows in the sky, especially when the sun comes out again after a rain shower.
A rainbow is the result of drops of water being illuminated by the sun--which is why you seldom see them on a dry day. But you don't need rain to fake a rainbow. Turn the page to find out how you can make one of your very own ... pot of gold not included!
build it What You'll Need: (a) A shallow glass dish (b) Water (c) A mirror (d) A white sheet of cardboard (e) A sunny day (f) An adult helper [ILLUSTRATIONS OMITTED] step by step (1) Put the shallow glass dish flat on the ground. (2) Place the mirror in the dish, leaning it up against one side. (3) Turn the dish so that the mirror faces the sun. (4) Fill the dish halfway with water. (5) Have your adult helper hold up the paper at the end of the dish opposite the mirror and move it around slowly. Watch for the sunlight bouncing off the mirror--your own rainbow! here's what happened The water in the dish bent the sunlight, breaking it up into the different colours that make up "white" light: red, orange, yellow, green, blue, indigo and violet. This process is called refraction, and it's the same way sunlight works to produce a rainbow in the sky!
There are two main kinds of rainbows:
A primary rainbow is the rainbow you see when you have your back to the sun. It is the result of sunlight being reflected once from the inner surface of a raindrop. A primary rainbow usually has a red band on the outer surface of the arc and blue or violet bands on the inner surface of the arc.
A secondary rainbow is the rainbow you sometimes see outside the primary rainbow. It is the result of sunlight being reflected twice from the water in the sky. This double-reflection reverses the colour sequence: a red band is usually on the inner surface of the arc, and blue or violet arcs on the outside. Because there is a loss of light with each reflection, the secondary rainbow is usually not as bright as the primary rainbow.
The legend that pot of gold lies at the end of a rainbow dates back to Old Europe. According to Irish folklore, the gold is placed there by fairies and guarded by leprechauns.
did you know ...
* The sun is always behind you when you see a rainbow, and the rain is always in the opposite direction: towards the rainbow's central arc.
* While a rainbow appears to be made up of red, orange, yellow, green, blue, indigo, and violet, it is actually made up of an entire continuum of colours, including ones that are invisible to the human eye.
* It's impossible to follow the arc of a rainbow below the horizon (which is why you'll never get that pot of gold!). Still, the higher you are above ground, the more of a rainbow you'll see. From an airplane, a rainbow appears as a complete circle, with the shadow of the plane in the centre.
* A rainbow's colour spectrum can best be seen with polarized sunglasses.
* You can never actually reach the end of a rainbow. As you move, the rainbow that your eyes see moves as well, because the raindrops are at different spots in the atmosphere. The rainbow appears to move away at the same rate that you approach it.
* The bands of colour in a rainbow are formed by the reflection and refraction of the sun's rays in the drops of rain in the sky. This process illuminates the red, yellow, green, blue and violet hues that are present in light that appears normally to be white.
1. In a primary rainbow, the colour red is usually found:
a. On the inner surface of the arc
b. In the middle of the arc
c. On the outer surface of the arc
d. There is no red in a primary rainbow
2. The most common seasons for rainbows are:
a. Winter and Autumn
b. Autumn and Spring
c. Summer and Autumn
d. Spring and Summer
3. In a secondary rainbow, light is reflected through raindrops:
c. Three times
d. Light is not reflected through raindrops
4. If you see a rainbow from an airplane, it will appear in what shape?
a. An arc
b. A circle
c. A diamond
d. You can't see rainbows from airplanes
5. What kind of glasses are best for seeing the spectrum of colours in a rainbow?
a. Coke-bottle glasses
b. Polarized sunglasses
c. Any kind of sunglasses
d. 3-D glasses
6. A rainbow illuminates colours in the sky that normally appear to be what colour?
7. According to legend, what do you normally find at the end of a rainbow?
a. A leprechaun
b. Another rainbow
C. A pot of chocolate coins
d. A pot of gold
8. Where is the sun when you see a rainbow?
a. In front of you
b. To your left
c. Behind you
d. Directly overhead
9. Which of the following colours do you normally not see in a rainbow?
10. Why is a secondary rainbow usually not as bring as a primary rainbow?
a. There is a loss of light with every reflection
b. It has fewer colours
c. It is smaller
d. It is not produced by light ###########
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|Date:||Jun 22, 2008|
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