Waves, Light & Sound

Light & ColorRecap, Wrap-Up & movin’ on

How do we see?

• Light passes – through the cornea– Through the aqueous humor– Through the pupil– Through the lens– Through the vitreous humor

• And then is detected by the rods & cones of the retina

How light is focused depends on…

–the shape of the • cornea• lens (which changes)•eyeball

Light images are

• Upside down on the retina• Transmitted to the brain by the optic

nerve• Flipped by the brain so we see them

right side up

If images aren’t focused correctly…

• Vision problems occur– Myopia (nearsighted)• Only see things close to you

– Hyperopia (farsighted)• Only see things far away from you

– Presbyopia• Farsightedness in old people

– Astigmatism• Blurred vision

Colors

• White is ALL colors of light reflected back at you

• Black is all colors of light absorbed and NONE reflected back at you

• When an object has color, you see that color reflected the most– Eg: a red apple appears red because only red light

is reflected back at you

Primary Colors of Light

• Red • Blue• Green

Colors that Cones can sense:

• Red• Blue• Green

(Are you SEEING a pattern here?)

Primary Colors of Pigments

• Dyes added to make colors–Cyan (blue)–Magenta (pink)–Yellow

What is the difference between dyes and pigments?

• Dyes are dissolved in whatever solvent is used. Pigments are insoluble.

• A pigment is a coloring matter, usually in the form of an insoluble powder that is mixed with oil, water, etc. to make paint. The pigment lays on the surface and becomes part of the dry film.

• A dye is soluble in water and is used to color cloth, basket reed and other porous materials.