This lab would be great for a lesson on stimulus response OR during a segmented worms unit. In the lab, students work with a live earthworm purchased from a local bait shop. They put the earthworm through a series of safe, animal-friendly tests to see how it responds to stimuli such as light, moisture, and vinegar. At the same time, students are assessed on their knowledge of earthworm anatomy, answering questions on structures such as the clitellum and prostomium. The lab lasts an entire period with a few conclusion questions for homework. Materials required are earthworms, vinegar, construction paper, rulers, water, and trays for the worms (I typically use dissection pans).