1. Sensation and Perception

2. Vision  Believe what we see first and other senses are 2 nd  Light starts from sun (or light bulb) as white light – color seen as waves of white light hit objects and bounce back to us at different speeds (diff. light wavelengths)

3. The Structure of the Eye

4.  Cornea: clear outer covering with fluid behind – the shiny part you see in mirror is a reflection of the fluid  Iris: colored circular muscle that opens and closes into larger and smaller circles in order to control the amount of light getting into the eye  Lens: helps you focus on the objects you see onto the back of the eye where there are receptors (think camera lens)  Pupil: an opening that changes size as the iris muscles move to cover and uncover the lens – looks black because it is dark inside eye – but flashing a light inside causes the colors to come out (dr. visit)  Get smaller when we see something unpleasant and larger when we see something we like – open all the way when one is afraid

5.  Retinas: made up of millions and millions of receptors  Rods: sensitive to the violet-purple range of wavelengths – used for night vision because they respond well to low levels of light; heavily packed into sides of retina – see better at night from the side  Cones: used in daylight for color – respond best to wavelengths in the red range  Retinal receptors are to the right or left of the optic nerve - area where there none called the blind spot – no light waves are picked up here, but eyes move so rapidly we usually don’t notice  Color vision – we see red, green and blue or a mix of the colors  Color blindness – inability to see colors – see yellow-blue; truly color blind people are rare  http://www.colour-blindness.com/colour-blindness-tests/ishihara-colour-test-plates/ http://www.colour-blindness.com/colour-blindness-tests/ishihara-colour-test-plates/  http://kidshealth.org/kid/talk/qa/color_blind.html http://kidshealth.org/kid/talk/qa/color_blind.html  Afterimages: results from remaining ‘unused’ cones firing so that all the cones can restore themselves to equal chemical levels