How do I see color? Photochemical receptors receive the light (____ and _____) Rods-brightness cones-the color They release a ________ signal to the brain. Brain interprets the signal Primary colors of light: red, blue, green (mix together to make white.)

Optics and Reflection Optics-the study of how light behaves Deals with the collection and use of light to create images Includes: lenses, mirrors, and ______ Law of __________: determines the reflected ray Light rays bounce off a mirror at the same angle at which they arrive We always define angles relative to the normal (the line perpendicular to the mirror (or lens)

Mirrors & Prisms Mirrors reflect light – Flat mirrors show _______ – Curved mirrors cause light to come together or spread apart Prisms cause light to change directions – Traditionally used to ________ the colors of light and to show how light bends

Reflection & Mirrors A mirror reflects rays of light so that they change their path ___________– the ray that comes from the object and hits the mirror ___________– the ray that bounces off the mirror

Refraction and Lenses A ____ uses __________ to cause light to come together or spread apart Refraction – The bending of light that occurs when light crosses a boundary between two different substances – EX. Glass, Plastic, Water ____ – a shape of transparent material that is used to bend the light rays – Shape determines how much the light bends

Focal Point & Focal Length ___________– the point at which light rays meet after having entered a converging lens parallel to the principal axis. ____________- the distance from the center of the lens to the focal point Where is the focal point in this eye diagram? Where is the focal length?

Lens Types Converging lenses – bend parallel light rays passing through them inward ______ the focal point Diverging lenses – bend the parallel light rays passing through them outward ______ from the focal point

The Eye Lens, cornea, iris, retina optic nerve Two convex lenses, refraction

Lens The lens can change it’s shape to focus at different distances. A lens that focuses in front of the retina is a condition called myopia (near sightedness) A lens that focuses objects behind the retina is a condition called hyperopia (far sightedness) Long Focal Length Short Focal Length Use Diverging Lens Thicker on sides than in center Use Converging Lens Thick in center than on the sides