Larry Jefferson, age 12, of Dallas,; Texas., for his question:

What exactly are the colors of the rainbow?

Now is the time to meet Mr. Roy G. Biv, for the letters in his name give us the banded colors of the rainbow. They are red, orange, yellow, green, blue indigo and violet, the first letters of which spell Roy G. Biv. Wizen we look at a rainbowo however, it is not always easy to identify these colors. The glimmering arch seems to glow with fuzzy reds on the inside and then fade away to nothing at all at the outer rim of the bow.

This is because the seven rainbow colors merge and blend with one another. Between red and orange bands, for example, there are countless shades and tints of reddish orange and orangy red. There is no telling how many different colors are displayed in a rainbow. Certainly there are all the colors we ever see in the world and perhaps more besides.

Actually, these rainbow colors are hidden in every sunbeam. We call this white light, though actually it is colorless. Light, of course, travels at 186,000 miles a second and every sunbeam comes in a straight line from the sun. It covers the 93 million miles in about eight minutes.

Light travels in continuous pulses of energy called waves. Each wave has a peak and a trough and these little ups and downs occur many times in a second. We call them wave lengths. Each sunbeam is really a number of different wave lengths, some shorter, some longer.

When a sunbeam,, with its different wave lengths,, strikes the curved surface of a raindrop, it is forced to bend. The shorter wave lengths bend most, the longer wave lengths bend least. This bending fans out the different wave lengths of light and they show up as different colors. The red amys of light have the short wave lengths, the blue rays have the longer wave lengths. All the other wave lengths are fanned out tomake the skein of rainbow colors.

The rainbow is really a trick with mirrors. The sun provides the stage lighting and a dark rain cloud provides the back drop for the stage. The mirrors are a myriad of falling raindrops, each with a clear round surface.

We never see a rainbow directly overhead, though from an airplane we may see the two halves of a bow making a circle on a rain cloud below us. From the ground, the rainbow occurs in the morning or late afternoon sky. It is in the opposite side of the sky from the sun. The glimmering arch appears when there are patches of clear sky and ragged rain clouds.

You look at the rainbow With your back towards the sun. The white sunbeams, hiding their skein of colors, rush over your shoulder and strike the dark rain cloud low in the sky. There they hit countless falling raindrops. Each raindrop bends and reflects the sunbeams back to your eyes. In so doing, they split the rays of light, each according to its own wave length. The reflected sunbeam shows up in its rainbow colors.