How do you make a simple model showing how the eye works?
You will need a large cardboard box, about 2 foot square, a small piece of aluminum foil, wax paper, and masking tape. Plus scissors and a pencil. First, tape the box shut so it is sealed on all four sides. Then on one side, cut out a small square hole about 2x2". Put the piece of aluminum foil over the hole and seal it on all four edges with masking tape. Then poke a small hole in the middle of the foil with a pencil, but make the hole very small, maybe half the diameter of the pencil, or even a bit less. On the opposite side of the box from the pencil hole, cut a square out just slighlty smaller than the largest square you can cut out of the wax paper, maybe 12x12". Place the wax paper over the cut out square and seal all four edges with masking tape. Now take the box and go to a room that has all the lights off and all the windows covered except one. Point the pencil hole side of the box out the window on a sunny landscape and look at the back of the box. There should be an upside down image on the wax paper. That is very much like how your eyes work, making an upside down image on your retina. Good luck, have fun!