Color (13.4)

By: Kayla Davis & Shynia Barksdale3rd period

Objectives❖ Recognize how additive colors affect

the color of light❖ Recognize how pigments affect the

color of reflected light❖ Explain how polarized light is formed

and detected

IntroductionIn this lesson we will learn how adding certain colors affects the color of light, how pigments affect the color of reflected light, and how polarized light is created and detected.

Additive Color SynthesisA method of creating color by mixing various portions of 2 or 3 distinctive stimulus colors of light.

Primary Colors are Blue, Green, & Red.

1 Red + 1 Blue = Magenta

1 Blue + 1 Green = Cyan

1 Green + 1 Red = Yellow

❖ Two Equal Primary colors create a Secondary color :

1 Red + 1 Blue + 1 Green = White

❖ Equal Stimulus Proportions of all three Primary colors create White :

2 Red + 1 Green = Orange

2 Green + 1 Red = Lime

1 Blue + 1 Green + 4 Red = Brown

❖ Unequal Proportions of Two or Three Primaries create other colors :

Pigments and Reflected Light❖ Pigments are molecules that Reflect

one specific wavelength of light and Absorb all others.

❖ So, the color we see is a net effect of all the light reflecting back at us.➢ Ex) We see an Apple being RED because it

has absorbed every other color, and is reflecting the red we see.

The Color of Light and Pigments Combine to create Colors

HOW?❖ The sun emits a

radiation which we see as the “Rainbow”

❖ The colors seen is the Visible Spectrum

❖ (ROYGBIV)➢ Red➢ Orange➢ Yellow➢ Green➢ Blue➢ Indigo ➢ Violet

Reflection & Absorption ❖ To be either reflected or absorbed

depends on what the wave hits to give it’s color.

❖ Solids easily reflect light

❖ For an object to be black, all light is absorbed, no light is reflected

Reflection and Absorption

Reflection

❖ Solids easily reflect light.

❖ Reflected light is the color you see

Absorption ❖ Black objects absorb

all light, reflecting no light.

❖ Absorbed Light is the colors you can't see

To be either reflected or absorbed depends on what to wave hits to give its color.

How Can We See Light?❖ Special rods in our eyes that are

receptive to light❖ Special cones in our eyes that are

sensitive to color❖ Not everyone can see the exact same

color or shade

Absorption Filters ❖ Commonly manufactured from dyed

glass or pigmented gelatin resin.❖ Operate by decreasing light through

absorption of specific wavelengths.❖ The result depends on the physical

thickness of filter and amount of dye present.

http://micro.magnet.fsu.edu/primer/java/filters/absorption/

William Perkin❖ In 1856, accidentally discovered

natural substance “Aniline Purple” or “Mauveine” at the age of 18

❖ Learned the chemical produced beautiful deep purple colored when dissolved in alcohol to make dye products

Polarization Definition ❖ Light waves or any other radiation are

restricted in one direction of vibration.

Characteristics of Polarization Waves

❖ They are basically a light wave that’s vibrating in more than one plane.

❖ Also are transverse waves that can be vertical or horizontal.

❖ They move in a linear line.

How is Polarized Light Formed? Polarized light is created by a single vibration electron emitting an electromagnetic wave that is polarized on a single plane.

Simply, it’s single light wave reflecting in a straight line. The way we might see this in nature would be like a type of glare.

How Can We See Polarized Light?The human eye lacks the ability to determine the difference between randomly oriented light and polarized light. It shows up as a glare in our eyes. This is why we use polarized sunglasses to reduce that glare.

How Polarized Sunglasses WorkPolarized sunglasses reduces the glare that is seen on many surfaces. They use a special filter that limits how much light can pass through. The filters has to be aligned certain way to allow light to pass and reduce the bright glare from our eyes.

References ★ Additive Color Synthesis. (n.d.). COLOR THEORY. Retrieved October 29, 2013, from

http://home.bway.net/jscruggs/add.html

★ Davidson, M. W. (n.d.). Polarization of Light. Molecular Expressions . Retrieved October 29, 2013, from

http://micro.magnet.fsu.edu/primer/lightandcolor/polarizedlighthome.html

★ Davidson, M. W. (n.d.). Molecular Expressions. Absorption Filters. Retrieved October 29, 2013, from

http://micro.magnet.fsu.edu/primer/java/filters/absorption/

★ Hewitt, P. G. (2009). Light. Conceptual Physics (pp. 532-573). Upper Saddle River : Prentice Hall .

★ Light and Color . (n.d.). Resources for Science Learning. Retrieved October 29, 2013, from

http://www.fi.edu/color/

Questions???