14.4 color and polarization

1. Recognize how additive colors affect the color of light

2. Recognize how pigments affected the color of reflected light.

3. Explain how linearly polarized light is formed and detected.

Color • The interaction of sunlight with matter can result in one of three

wave behaviors: ____________________________________

• __________________________________________________.

• The color of the objects that we see are largely due to the way those objects reflect or transmit the light to our eyes. The color of an object is not actually within the object itself. Rather, the color is in the light that shines upon it and is ultimately reflected or transmitted to our eyes.

Additive and subtractive primary colors of light

Additive primary colors of light: ___________________

Additive primary colors produce _______________ when combined.

Subtractive primary colors of light: ___________________ Subtractive primary

colors _________ all light when combined.

Blue Skies• The two most common types of matter present in the

atmosphere are gaseous nitrogen and oxygen. These particles are most effective in _____________________________ portions of the visible light spectrum such as blue and violet light. This scattering process involves the absorption of a light wave by an atom followed by reemission of a light wave in a variety of directions.

• All high frequency light are scattered. However, our eyes are more sensitive to light with blue frequencies. Thus, we view the skies as being blue in color.

What Makes a Red Sunset? • There are two reasons:

1. As the Sun gets lower in the sky, its light is passing through more of the atmosphere to reach you. Even ________________________________, allowing the reds and yellows to pass straight through to your eyes.

2. The sky appears red because ________

______________________, pollution, and water vapor in the atmosphere reflect and scatter more of the reds and yellows.

Polarization of light waves• Light is a transverse wave that vibrate in

________________planes. A light wave which is vibrating in more than one plane is referred to as ______________________light.

• Polarized light waves are light waves in which the vibrations occur in __________________________.

• The most common method of polarization involves the use of a Polaroid filter. Polaroid filters are made of a special material which is capable of blocking one of the two planes of vibration of an electromagnetic wave. When unpolarized light is transmitted through a Polaroid filter, it emerges with one-half the intensity and with vibrations in a single plane; it emerges as polarized light.

Light can be polarized

Note: a longitudinal wave ____________ be polarized. ___________ wave is a longitudinal wave, sound wave _________________________________.

Applications of PolarizationUsed in ______________________________________. • Light reflected from surfaces such as a flat road or

smooth water is generally horizontally polarized. This creates an annoying and sometimes dangerous intensity of light that we experience as glare.

• Polarized lenses contain a special filter that blocks this type of intense reflected light, reducing glare.

• Polarization is also used in the entertainment industry to produce and show ___________________. Three-dimensional movies are actually two movies being shown at the same time through two projectors.

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Class work – today’s date1. Sunlight is composed of various intensities of all

frequencies of visible light. The graph represents the relationship between light intensity and frequency. Based on the graph, which color of visible light has the lowest intensity?

a. violet b. red c. blue d. yellow e. green f. orange

2. It has been suggested that fire trucks be painted yellow green instead of red. Based on the information from the graph, which is the best explanation of the advantage of using yellow-green paint instead of red?

a. Yellow green is brighter than red. b. Red has a higher frequency than yellow green. c. Yellow green has a lower intensity than red. d. The brightness of the colors is proportional to their

frequencies

3. As the color of light changes from red to yellow, the frequency of the light

a. decreases

b. increases

c. remains the same

4. The diagram shows a beam of light entering and leaving a "black box."  The box most likely contains a

a. prism

b. converging lens

c. double slit

d. polarizer

5. Which phenomenon does not occur when a sound wave reaches the boundary between air and a steel block?

a. reflection

b. refraction

c. polarization

d. absorption

6. The diagram shows sunglasses being used to eliminate glare. Which phenomenon is being represented in the diagram?

a. dispersion

b. diffraction

c. internal reflection

d. polarization

7. A house is painted with pigments that reflect red and blue light but absorb all other colors.

a. What color does the house appear to be when it is illuminated by white light?

b. What color does it appear to be under green light