Grown-Ups
Help your camper fill a bag with small objects from their CKJR Toolkit—markers, figurines, etc. Then help them observe their eye in a mirror, noting the pupil. Turn out the lights and enjoy experimenting with night vision: Can they guess what objects they're pulling from the bag? Use the flashlight to continue experimenting with how they see in the light and dark. Help them observe how their pupil changes when the light comes back on. (Note: The link suggests experimenting with both red and white lights, but most of us don't have a red flashlight lying around. Use what you've got!)
Kids
Put some of your figurines and markers in a bag. Then turn out the lights or go outside with your grownup. Pull an object out of the bag. Can you guess what it is, even in the dark? Using your flashlight, experiment with what you can see in the dark and light. What happens to your eyes when you turn on a light?