Color

What can the human eye NOT see? A. Infrared radiation B. Ultraviolet radiation C. Both A and B. D. Neither A nor B.

Both A & B

A white sky is evidence that the atmosphere contains: A. predominantly small particles. B. predominantly large particles. C. a mixture of particle sizes. D. pollutants.

C. A mixture of particle sizes

A variety of sunset colors is evidence for a variety of: A. elements in the Sun. B. apparent atmosphere thickness. C. atmospheric particles. D. primary colors.

C. atmospheric particles.

Why are clouds white?

Clouds -- clusters of various sizes of water droplets Size of clusters determines scattered cloud color - Tiny clusters produce bluish clouds. - Slightly large clusters produce greenish clouds. - Larger clusters produce reddish clouds. - Overall result is white clouds. - Slightly larger clusters produce a deep gray. - Still larger clusters produce raindrops.

Why are sunsets red?

Light that is least scattered is light of low frequencies, which best travel through air. Red Orange Yellow

Mixed colored lights Additive primary colors

Red, green and blue Produce any color in the spectrum

The color we see depends on what?

The frequency of light Lowest frequency—perceived (seen) as red In between lowest and highest frequency—perceived as colors of the rainbow (red, orange, yellow, green, blue, indigo, violet) Highest frequency—perceived as violet Beyond violet, invisible ultraviolet (UV)

Color of lakes in the Canadian Rockies

The intriguingly vivid blue of lakes in the Canadian Rockies is due to scattering. The lakes are fed by runoff from melting glaciers that contain fine particles of silt, called rock flour, which remain suspended in the water. Light scatters from these tiny particles and gives the water its eerily vivid color.

Why is the sky blue?

The sky is blue because of selective scattering (selective scattering of smaller particles than the wavelength of incident light and resonances at frequencies higher than scattered light) Blue scattered light predominates (is the strongest element) in our vision. The tinier the particle, the higher the frequency of light it will re-emit. Varies in different locations under various conditions: Clear dry day—much deeper blue sky Clear, humid day—beautiful blue sky Lots of dust particles and larger molecules than nitrogen and oxygen in the atmosphere—less blue sky with whitish appearance After heavy rainstorm (washing away of airborne particles)—deeper blue sky

True or False?: Objects reflect light of some frequencies and absorb the rest.

True. Rose petals absorb most of the light and reflect red. Objects that absorb light and reflect none appear black. Objects can reflect only those frequencies present in the illuminating light.

Subtractive primary colors - Combination of two of the three additive primary colors:

red + blue = magenta red + green = yellow blue + green = cyan

Color is in the eye of...

the beholder (the one who is looking; observing)

Only three colors of ink (plus black) are used to print color photographs. What are they? What does the addition of black do?

—(a) magenta, (b) yellow, © cyan - the addition of black produces the finished result

Color of transparent object depends on...

Color of transparent object depends on color of light it transmits. Colored glass is warmed due to the energy of absorbed light illuminating the glass.

If molecules in the sky scattered orange light instead of blue light, sunsets would be: A. orange. B. yellow. C. green. D. blue.

D. Blue Explanation: Of the colors listed, blue is closest to being the complementary color of orange.

When the color yellow is seen on your TV screen, the phosphors being activated on the screen are: A. mainly yellow. B. blue and red. C. green and yellow. D. red and green.

D. Red & Green

Red, green and blue light overlap to form what? A. red light B. green light C. blue light D. white light

D. White light

Mixed colored lights Mixed distribution of solar frequencies is even or uneven?

Uneven Most intense in yellow-green portion (where our eyes are most sensitive) Radiation curve divides into three regions that match the color receptors in our eyes.

Why is water greenish blue?

Water molecules resonate somewhat in the visible red, which causes red light to be a little more strongly absorbed in water than blue light. Red light is reduced to one-quarter of its initial brightness by 15 meters of water. There is very little red light in the sunlight that penetrates below 30 meters of water. When red is removed from white light, the complementary color of red remains: cyan—a bluish-green color.

Selective Reflection

We see the color of a rose by the light it reflects