Is it scattering or reflection that accounts for the

Color in Our World Which has the higher frequency: red light or blue light?

Selective Reflection What occurs when the outer electrons that buzz about the atomic nucleus encounter electromagnetic waves?

Selective Reflection What happens to light when it falls on a material that has a natural frequency equal to the frequency of the light?

What happens to light when it falls on a material that has a natural frequency above or below the frequency of the light?

What color light is transmitted through a piece of red glass?

How does a pigment affect light?

What is the evidence for the statement that white light is a composite of all the colors of the spectrum?

Which warms more quickly in sunlight: a colorless or a colored piece of glass? Why?

What is the color of the peak frequency of solar radiation?

To what color of light are our eyes most sensitive?

What is a radiation curve?

What frequency ranges of the radiation curve do red, green, and blue light occupy?

Why are red, green, and blue called the additive primary colors?

What is the resulting color of equal intensities of red light and cyan light combined?

Why are red and cyan called complementary colors?

When something is painted red, what color is most absorbed?

What are the subtractive primary colors?

If you look with a magnifying glass at pictures in a book or magazine that are printed in full color, you’ll notice three colors of ink plus black. What are these colors?

Which interact more with high-pitched sounds: small bells or large bells?

Which interact more with high-frequency light: small particles or large particles?

Why does the sky normally appear blue?

Why does the sky sometimes appear whitish?

Why does the Sun look reddish at sunrise and sunset but not at noon?

Why does the color of sunsets vary from day to day?

Is it scattering or reflection that accounts for the whiteness of a cloud?

What is the effect on the color of a cloud when it contains an abundance of large droplets?

What part of the electromagnetic spectrum is most absorbed by water?

What part of the visible electromagnetic spectrum is most absorbed by water?

What color results when red is subtracted from white light?

Why does water appear cyan?

Send a message to Grandma and tell her what details you’ve learned that explain why the sky is blue, sunsets are red, and clouds are white. Discuss whether or not this information adds to or decreases your perception of the beauty of nature.

What color of visible light has the longest wavelength? The shortest wavelength?

Why don’t color scientists list black and white as colors?

Why are the interiors of optical instruments intentionally black?

Fire engines used to be red. Yellow-green is now the preferred color. Why the change?

Tennis balls used to be white. What is their color today, and why?

Why does a white piece of paper appear white in white light, red in red light, blue in blue light, and so on for every color?

What color does red cloth appear to be when illuminated by sunlight? By light from a red neon sign? By cyan light?

A spotlight is coated so that it won’t transmit yellow light from its white-hot filament. What color is the emerging beam of light?

How could you use the spotlights at a play to change the performers’ clothes suddenly from yellow to black?

Does color television operate by color addition or by color subtraction? Defend your answer.

On a TV screen, red, green, and blue spots of fluorescent materials are illuminated at a variety of relative intensities to produce a full spectrum of colors. What dots are activated to produce yellow? Magenta? White?

What colors of ink do color ink-jet printers use to produce a full range of colors? Do the colors form by color addition or by color subtraction?

Streetlights that use high-pressure sodium vapor produce light that is mainly yellow with some red. Why aren’t dark blue police cars advisable in a community that uses these streetlights?

In which of these cases will a ripe banana appear black: when illuminated with red, yellow, green, or blue light?

What color of light will be transmitted through overlapping cyan and magenta filters?

Look at your red, sunburned feet when they are under water. Why don’t they look as red as when they are above water?

Why does the blood of injured deep-sea divers look greenish-black in underwater photographs taken with natural light, but red when flash is used?

By reference to Figure 27.9, complete the following equations: Yellow light + blue light = _______ light Green light + _______ light = white light Magenta + yellow + cyan = _______ light

Your friend says that red and cyan light produce white light because cyan is green + blue, and so red + green + blue = white. Do you agree or disagree, and why?

Check Figure 27.9 to see whether the first three statements are accurate. Then complete the last statement. (All colors are combined by the addition of light.) Red + green + blue = white Red + green = yellow = white - blue Red + blue = magenta = white - green Green + blue = cyan = white - _______

At the beach, you can get a sunburn while under the shade of an umbrella. What is your explanation?

When white light is shone on red ink dried on a glass plate, the color that is transmitted is red. But the color that is reflected is not red. What is it?

Pilots sometimes wear glasses that transmit yellow light and absorb light of most other colors. Why does this help them see more clearly?

Does light travel faster through the lower atmosphere or through the upper atmosphere?

Your friend says that the reason the distant dark mountains appear blue is because you’re looking at the sky between you and the mountains. Do you agree or disagree?

Comment on this statement: “Oh, that beautiful red sunset is just the leftover colors that weren’t scattered on their way through the atmosphere.”

Why does smoke from a campfire look blue against trees near the ground but yellow against the sky?

If the sky on a certain planet in the solar system were normally orange, what color would sunsets be?

Volcanic emissions spew fine ashes in the air that scatter red light. What color does a full Moon appear to be through these ashes?

What accounts for some clouds being white and others dark?

Why is the foam of root beer white, while the beverage is dark brown?

Very big particles, like droplets of water, absorb more radiation than they scatter. How does this relate to the darkness of rain clouds?

How would the whiteness of snow appear if Earth’s atmosphere were several times denser?

The atmosphere of Jupiter is more than 1000 km thick. From the surface of Jupiter, would you expect to see a white Sun?

Red sunrises occur for the same reason as red sunsets. But sunsets are usually more colorful than sunrises— especially near cities. What is your explanation?

You’re explaining to a youngster at the seashore why the water is cyan colored. The youngster points to the whitecaps of overturning waves and asks why they are white. What is your answer?

In a boutique store with only fluorescent lighting, a customer insists on taking dresses into the daylight at the doorway to check their color. Discuss whether she is being reasonable

Why is red paint red?

If the sunlight were somehow green instead of white, what color clothing would be most advisable on an uncomfortably hot day? On a very cold day?

Why will the leaves of a red rose be warmed more than the petals when illuminated with red light? Discuss how this relates to people in the hot desert wearing white clothes.

The radiation curve of the Sun (see Figures 27.7 and 27.8) shows that the brightest light from the Sun is yellow-green. Why, then, don’t we see the Sun as yellow-green?

Suppose that two flashlight beams are shone on a white screen, one through a pane of blue glass and the other through a pane of yellow glass. What color appears on the screen where the two beams overlap? Suppose, instead, that the two panes of glass are placed in the beam of a single flashlight. Discuss what colors then appear.

Your friend reasons that magenta and yellow paint mixed together will produce red because magenta is a combination of red and blue and yellow is a combination of red and green—and that the color in common is red. Do you agree or disagree, and why?

Science author Suzanne Lyons is shown with son Tristan wearing red and daughter Simone wearing green in one of the opening photos for this chapter. Note that the negative of the photo shows these colors differently. Discuss and explain.

Stare intently at an American flag. Then turn your view to a white area on a wall. What colors do you see in the image of the flag that appears on the wall?

Why can’t we see stars in the daytime?

Why is the sky a darker blue when you are at high altitudes? (Hint: What color is the “sky” on the Moon?)

There is no atmosphere on the Moon to produce scattering of light. Discuss how the daytime sky of the Moon would appear when viewed from the Moon’s surface.

Can stars be seen from the Moon’s surface in the “daytime” when the Sun is shining?

Discuss the color of the setting Sun as seen from the Moon.