Refraction and Internal Reflection A scuba diver is floating beneath the ice in Antarctica. Amy Moran, UH Professor, diving in Antarctica (Photo credit: Steve Rupp) She shines a light to get around and notices that the beam sometimes does not pass into the air above the ice. What is this threshold angle (respect to the normal)? What would it be if she dove in Hawai'i (without the ice)? The indices of refraction of water and ice are 1.33 and 1.31 respectively