The Rattlesnake Venom Study Lab puts students in the role of investigators to evaluate the action of venom from 6 Crotaline (rattlesnake) species on human blood clotting times. They can also choose to test the effects of a fast acting anticoagulant. The lab includes a short background, purpose, list of materials and setup instructions. The supplies are cheap and allow students to retest several times if needed. This lab is part of the "How Venom Affects Humans" NGSS lesson plan.