Seeing Light Chapter 2 Section 4

Vocabulary Cornea – the clear tissue that covers the front of the eye Cornea – the clear tissue that covers the front of the eye Pupil – the opening through which light enters Pupil – the opening through which light enters Iris – a ring of muscle that contracts and expands to change the size of the pupil Iris – a ring of muscle that contracts and expands to change the size of the pupil Retina – a layer of cells that lines the inside of the eyeball Retina – a layer of cells that lines the inside of the eyeball

Rods – cells that respond to light Rods – cells that respond to light Cones – cells that respond to color Cones – cells that respond to color Nearsighted – vision where a person can see nearby things clearly but objects at a distance are blurred Nearsighted – vision where a person can see nearby things clearly but objects at a distance are blurred Farsighted – vision where a person can see distant objects clearly, but nearby objects appear blurry Farsighted – vision where a person can see distant objects clearly, but nearby objects appear blurry

Gold Keys When light from an object hits your eye, your eye sends a message to your brain to see the object When light from an object hits your eye, your eye sends a message to your brain to see the object Concave lenses are used to correct nearsightedness. Convex lenses are used to correct farsightedness Concave lenses are used to correct nearsightedness. Convex lenses are used to correct farsightedness

General Notes Cornea – protects the eye, acts as a lens to help focus light rays Cornea – protects the eye, acts as a lens to help focus light rays Iris gives eye its color Iris gives eye its color Light enters pupil, goes through the lens which bends it and forms an upside-down image on the retina Light enters pupil, goes through the lens which bends it and forms an upside-down image on the retina Retina is made up of rods and cones Retina is made up of rods and cones Rods and cones help change images on the retina into signals that travel to the brain along the optic nerve Rods and cones help change images on the retina into signals that travel to the brain along the optic nerve Nearsightedness – eyeball is too long, lens focuses the image in front of the retina Nearsightedness – eyeball is too long, lens focuses the image in front of the retina Farsightedness – eyeball is too short, image that falls on the retina is out of focus Farsightedness – eyeball is too short, image that falls on the retina is out of focus