Welcome to You Ask Andy

  Paul Paulin Trm age 14, of St  Catharine:

Is it true that light is colored?

It is true that the colors we seep say, in a garden are caused by certain factors in light  Changes occur when the dazzling white light of the sun strikes the petals of a rose, the soil or the foliage, Our eyes register these changes as colors  A sunbeam is a small fraction of the vast electromagnetic energy which pours out in every direction from the sun  Traveling across the 92 million miles of space which separate us from the sun it reaches us in about eight minutes 

Its speed through space is about 186,284 miles a second and it travels in tiny pulses of energy called wave lengths  A wave length has a crest and a trough which can be measured  The unit for measuring the wave length is the angstrom, which is 100 millionth part of a centimeter, which means that there are roughly 250 million angstroms in one inch  The electromagnetic energy in a beam of sunlight pulses along in many different wave lengths, some longer and some shorter than others 

When a beam of white light passes through a glass prima, its different wave lengths are bent at different angles  They are separated and our eyes see the results as a rainbow, the band of radiant colors which the scientist calls the spectrum of visible light  The band of colors occurs in a certain order because of the gradual variation in the wave lengths 

The rainbow colors, as we know, run through red, orange, yellow, green, blue, indigo and violet  Each color is the result of the bending and reflecting of a certain wave length  The red rays have the longest wave lengths, up to 7,000 angstroms  The shortest are about 4,000 angstroms and they show us the deep violets  The thickness of a sheet of note paper is equal to about 130 of the red wave lengths and 260 of the blue wave lengths 

A certain percentage of this light energy is absorbed when it strikes a surface and the rest is reflected back for our eyes to see  The petals of a red rose absorb the orange,, yellows green and all the blue rays and the red is reflected back  A marigold absorbs all but the orange and yellow rays, A white lily absorbs but a small percentage of the light and reflects back all the rainbow colors, or white light for us to see, The coat of a black cat absorbs almost all of the light and we see no rainbow colors at all 

The visible spectrum by which we see colors is but a small percentage of the whole spectrum of sunlight.  Some of this electromagnetic energy pulses along in wave lengths too short and some 3n wave lengths too long for our eyes to see, The shortest of the blue wave lengths is 1,000 to 10,000 times longer than ultraviolet rays, Though invisible to our eyes, ultraviolet rays may give us a sunburn, even on a cloudy day,

Infrared rays have wave lengths longer than the red rays of the visible spectrum  They can pass through misty clouds  Though we cannot see them, we feel them as heat, They can be recorded on certain film and we can get a clear picture of the scenery through a thick fog,

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