Dark Adaptation

In this activity (6th on the page), learners investigate how photoreceptors in the eye (rods and cones) "adapt" to low light conditions. Learners sort similar bottle caps in a well-lit room and then attempt to resort them in the dark. Learners will observe that many make mistakes in sorting in the dark. The lights will remain dim while learners discuss dark adaptations and how animals can see in the dark. After about 7-10 minutes, learners will separate the caps again in the same dim conditions as before and find that learners make fewer errors because the photoreceptors adapted to the low light conditions.