3. White objects appear white because they reflect all the colors of the visible spectrum.

Even though the visible spectrum consists of seven different colors, all of the color seen by the human eye is a mixture of the three primary colors: red, green, and blue.

Red, green, and blue are the primary additive colors. When mixed together in different proportions, you can make just about any color. When mixed in equal proportions (added together), the three primary colors yield white light.

http://www.micro.magnet.fsu.edu/primer/java/scienceopticsu/light/additive.html

A pigment is a colored material that absorbs some colors and reflects others. The primary pigments are:

1. magenta2. yellow3. cyan

Cyan, Magenta, and Yellow are the primary subtractive colors. These colors are combined to produce print media and photographic film. When the subtractive primary colors magenta, cyan, and yellow are added together, they form the color black.

http://www.micro.magnet.fsu.edu/primer/java/scienceopticsu/light/subtractive.html

Color blindness occurs because one or more sets of cones do not function correctly.

Try these tests.http://colorvisiontesting.com/ishihara.htm#plate with 10

Eye correctly focusing on the retina

Eyeball is too long or the cornea bulges

Image is focuses before it reaches the retina

Corrected with concave lenses

Nearsightedness

Incorrect Focal point Correct Focal point

Eyeball is too short

Image is focuses behind the retina

Corrected with convex lenses

Farsightedness

focused incorrectly focused correctly

Farsightedness

Farsightedness

Prisms & Rainbows

• Prisms: Separates white light into its component colors. The longer the wavelength, the less it will be bent by the prism.

• Rainbows- light shining thru tiny droplets of water, each droplet acts as a prism

Interactions of Waves

• Refraction – The bending of a wave due to the wave moving from one type of medium into another. 1. As light rays enter a new

• medium the cause light to bend• 2. The denser the medium –• the slower the light travels

Interactions of Waves

Reflection – Bounce back wave• –Angle of Incidence is the angle of the wave

coming into the object reflecting the wave.• –Angle of Reflection is the angle bouncing off

and going away from the object

Interactions of Waves

•Diffraction – Wave passing a barrier or going through a hole in a barrier bends and causes the wave to wrap around the

Surface of the cornea is curved unevenly

Image is not focused in the right place

Corrected with a combination of lenses