Creating a model of the human eye and its structure help students understand the complexity of the human eye. Provide your child with complex images with human eyes from anatomy books and sketch the elements that make up the eye. If possible, take your child to an ophthalmologist and have him see the inside of an eye using an ophthalmoscope. Your child can build an eye model using paper mache or polystyrene foam.
Have your child test the pupillary light reflex -- the way the pupil dilates and contracts as the eye adapts to different intensities of light. Your child must know that the pupil is the dark point located at the center of the iris, and its size changes to adjust the amount of light that enters the eye. Your child will observe and measure the diameter of the pupil of up to 10 subjects in lights with different intensities. Have your child photograph the eyes (without camera flash) and measure the size of the pupils compared to the iris using the pictures. Based on the results, the student prepares three -- or more -- models of eyes with pupils of different sizes.
Arrange for a meeting with a cat and its owner and have your child look at the cat's eyes. Point out the third eyelid or the nictitating membrane, which is visible when the cat blinks and the size and shape of pupils -- in a cat's eye there is a narrow, elliptical-shaped opening during the day that becomes a sphere in low-light conditions. Have your child observe a human eye. Help him note a few differences between the human and cat eye anatomy. The child prepares a human eye model and a cat eye model for display.
This project involves building a box and placing three cards -- red, blue and green -- on the inside on one of the walls and a narrow opening on the wall opposing the colored cards. There should be a dim light inside the box. The student has 30 people with different eye colors look through 4 to 10 different filters and report what they see. The filters are neutral, so they don't change the colors, but only the intensity of the light. The student has to establish if eye color influences the way people see in low-light conditions. For display, the student can use brown, green and blue eye models.