three physical characteristics of light help determined our sensory experiences:
- wavelength, the distance from one wave push to the next that determines its hue (the color we experience such as pink and green
- intensity, the amount of energy in light waves (determined by a wave’s amplitude or height) which influence brightness
- saturation, refers to the purity or richness of color; the fewer the number of wavelengths mixed together, the more saturated, or ‘pure’ a color appears
light rays first pass through a transparent protective structure called the cornea
pupil
a round opening in which size varies with lightning conditions
- the less light present, the wider the pupil opening
iris
the colored part of the eye, which is the circular muscle that contracts or expands to let in varying amounts of light
lens
a clear structure in which shape adjusts to permit us to focus on objects at varying distances and are projected on the retina at the back of the eyeball
retina
a postage stamp sized structure that contains two types of light sensitive receptor cells: about 6.5 within cones and about 100 million rods
center of the retina called fovea, which is the area of clearest vision and plays a key role in color vision
