Trace around the opening of a coffee can on black construction paper. Cut out the circle and cut out an elongated oval in the center of the circle. Use a glue gun to glue a round mirror to the inside bottom of an empty coffee can. Tape the paper circle over the opening of the coffee can. Go into a dark room with a flashlight. Look for the coffee can. Turn on the flashlight and hold it away from you at eye level. Light will reflect from the mirror in the back of the can.
The pupils of a cat’s eyes open wider in the dark to allow more light to come in. You can experiment with your own eyes to see how this works. Stand in front of a mirror in a brightly lit location. Close one eye for two minutes. Look into the mirror as you open the other eye. Note the size of the pupil in the eye that was closed. When the eye was closed, the pupil opened large to try to let in more light. When you opened that eye in the bright light, the pupil became smaller, just like a cat’s eye.
Trace around the opening of a coffee can on black construction paper. Cut out the circle and use it as a pattern to make several other circles. Cut a different width of elongated oval out of each circle. Use a glue gun to glue a round mirror in the inside bottom of the coffee can. Tape a circle on the opening of the can. Go into a dark room with a flashlight. Hold the flashlight away from you at eye level and shine it toward the slit in the paper. Try the other sizes and determine the order of the “glow” from least to greatest.
Take a flashlight with you into a room with a cat with dark fur, either your cat, or the cat of a friend. Look at the cat’s eyes with the light on. Turn out the light and look for the cat. To find the cat, turn on the flashlight and search for the reflection of the flashlight when it hits the back of the cat’s eyes. The cat’s eyes don’t “glow” before you shine the flashlight into them.