Handboilers, perfect for teaching about thermal energy, are sold individually and in cases of 12 for your entire class. Heat-Sensitive Pencils will tell you that "you're getting warmer" as you make your point. These thermochromic pencils will actually change color with the heat from your hand! Place your hand on a Touch and See Square and create a beautiful thermal hand print. Each color represents a different temperature. Our Heat-Sensitive Paper changes color within the temperature range of 31oC (88oF) to 37oC (98oF). Add hot water to the Climate Change Mug and watch Florida and California disappear, as Central America becomes just a chain of islands! Click a metal disk in the Chemical Heat Pack and watch the liquid crystallize. Learn more about thermal energy in our Thermal Energy Newsletter.