light and colors. light vs pigments if light passes through a substance, the substance is said to be

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Light and Colors

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Page 1: Light and Colors. Light vs Pigments If light passes through a substance, the substance is said to be

Light and Colors

Page 14: Light and Colors. Light vs Pigments If light passes through a substance, the substance is said to be

Two colors of light are complementary if they produce white when added together. The

complementary pairs are: • Green and magenta

• Red and cyan

• Blue and yellow

Page 15: Light and Colors. Light vs Pigments If light passes through a substance, the substance is said to be

Pigments are chemicals that are used to produce different colors of paint or dyes.

The primary pigments absorb ONE primary color and reflect the other two primary colors back to our eyes.

The primary pigments are the same as the secondary colors.

• CyanCyan pigment absorbs pigment absorbs red and reflects back red and reflects back blue and green.blue and green.

• MagentaMagenta pigment pigment absorbs green and absorbs green and reflects blue and red.reflects blue and red.

• YellowYellow pigment absorbs pigment absorbs blue and reflects red and blue and reflects red and green.green.

Page 17: Light and Colors. Light vs Pigments If light passes through a substance, the substance is said to be

The sky is blue because the atmospheric molecules are in resonance with blue light.

The sky is blue because the atmospheric molecules are in resonance with blue light. When white light comes from the sun, the blue waves are absorbed and reemitted in all directions by the air molecules.

When white light comes from the sun, the blue waves are absorbed and reemitted in all directions by the air molecules.

So the sky will look blue and the sun will have “lost” a little of its blue waves so that it will look slightly yellow (red and green).

So the sky will look blue and the sun will have “lost” a little of its blue waves so that it will look slightly yellow (red and green).

This is called “Rayleigh scattering”.This is called “Rayleigh scattering”.

Page 18: Light and Colors. Light vs Pigments If light passes through a substance, the substance is said to be

The sunrises and sunsets look yellow and orange and red because the white light from the sun has to pass through so much more of the atmosphere to reach our eyes as we look towards the sun at the horizon. Because of that, virtually all of the blue light will have been scattered by the air molecules, leaving only red and green for us to see.

Page 19: Light and Colors. Light vs Pigments If light passes through a substance, the substance is said to be

The oceans look blue-green because the ocean waters (with algae and other microorganisms and impurities) absorb red light and only reflect back to our eyes the blue and green of the spectrum.