Chapter 16-2 Light and Matter

Color: the dispersion of white light into the color spectrum ROYGBIV

Newton did the first experiments demonstrating that white light contained all the colors in the spectrum

Light Transmission Terminology Transparent materials that transmit light waves without distorting images, e.g., glass Translucent materials that transmit light but do not permit objects to be seen clearly, e.g., tissue paper Opaque materials which transmit no light, e.g., brick

Color by Addition Primary Light Colors: Red, Blue, Green Secondary Light Colors: Magenta = red + blue Yellow = red + green Cyan = blue + green

Color by Addition

Color Addition

Color Addition

Color Addition

Color Addition

Color by Subtraction Primary pigments: absorb one primary color from white light: (yellow, cyan, magenta) and reflect two primary colors Secondary pigment: absorb two primary colors from white light: red, green blue Difference between dye and pigment: Dye-- a (molecule) that absorbs certain wavelengths of light, Pigment-- (particle)—colored material that absorbs certain wavelengths

Color by Subtraction

Thin Film Interference any film thickness equal to an odd multiple of quarter wavelengths will reinforce a given color. The spectrum of colors produced by an oil film on water is due to interference.

Polarization of Light Unpolarized light vibrates in all planes polarized light all vibrates in a particular plane

In a: only vertically polarized light is transmitted In b: only horizontally polarized light is transmitted

Polarization by Reflection Light reflecting off horizontal surfaces is horizontally polarized Vertically polarized sunglasses will cut down glare (filter out the horizontally polarized light)

End 16-2