WAVES AND COLOR

Most materials absorb light of some frequencies and reflect or transmit the rest.

FREQUENCY RANGE for VISIBLE LIGHT RED has the lowest frequency on the visible light spectrum. VIOLET has the highest frequency on the visible light spectrum.

How can I remember the order of colors in the visible spectrum? Roy G. Biv (in order from longest to shortest wavelength): Red Orange Yellow Green Blue Indigo Violet

If a material absorbs a certain frequency of light, that frequency will not be reflected, so its color will not be perceived by the observer. Example: If you are wearing a yellow shirt – your shirt only appears yellow because it is able to absorb R.O.G.B.I.V. and therefore reflects yellow at your eye.

If the material does not absorb a certain frequency of light, that frequency will be reflected, so its color will be perceived by the observer. CFU #1: Which colors are absorbed by the leaf? CFU #2: Which color is not being absorbed?

If all colors of light are reflected by a material, it will appear white. If all colors of light are absorbed by a material, it will appear black. Can you think of… POP QUIZ #3: A mineral that reflects all colors? POP QUIZ #4: A mineral that absorbs all colors?

So, the color we see depends on two things. What are they? 1.) The color of light shined on the object. 2.) The color of the light reflected by an object.

CFU #5: If an object reflects red wavelengths and absorbs all others, what color will the object appear? Color Filters allow only certain colors of light to pass/ transmit through them; they absorb all other colors.

CFU #6: What colors did the red color filter (at the beginning) transmit? What colors did it absorb?

What if we change the light source?

HOW DO WE SEE LIGHT?

Light comes through the pupil and splashes inside your eye on the retina. Hole in the front of your eye is called the pupil.

Your retina is filled with two kinds of special cells, rods and cones Your retina is filled with two kinds of special cells, rods and cones. Rods let you see black and white only. Cones let you see color.

You don't have any rods or cones where the optic nerve connects to your retina this causes you to have a blind spot. 1. Close your right eye. 2. With your left eye, look at the +. 3. You should see the red dot in your peripheral vision. 4. Keep looking at the + with your left eye.

Color Fatigue Effect Fatigue in cone cells due to staring at a certain color for a prolonged period of time.

Nearsighted vs. Farsightedness

The lens further focuses the light on the retina The lens further focuses the light on the retina. The image is flipped over and spread across the back of the retina. The retina then carries the light signals to the brain via the optic nerve.