You will have a human eye model setup that consists of an eye hold, two options for a human lens, and an adjustable retina screen that will displace your light source in fine detail when the setup is focused properly. your light source consists of a light bulb box that you can slide toward and away from the eyeball, with a ruler where you can measure the exact distances between all parts in the setup. you will also have weaker lenses that you can use to try to fix problems that arise when the eyeball not at the right size to complement the lens power provided by the eye muscles.

in activity 2, you will explore the human eye model when the human eye is the correct length and the muscles in the eye can squish and relax the eye such that the eye power ranges from +7 or +8 diopters to +20 diopters (meaning the lens is converging with focal length ranging from 1/7 or ⅛ to 1/20 meters). describe your experimental setup that will contrast where the light source must be located to focus with 7 or 8 diopter lens, vs. where the light source must be located to focus with the 20 diopter lens.