Potential energy is converted to kinetic energy. Kinetic energy is converted to heat energy. Hand Boilers, perfect for teaching about thermal energy, are sold individually and in cases of 12 for your entire class. Perfect for teaching your students about Newton's laws of motion, Newton's Cradle makes a great addition to any classroom. When Smashing! Steel Spheres are smashed together, enough heat is generated at the point of contact to burn a hole in a piece of ordinary paper! Simply moisten the Drinking Bird's head with water, place it next to a full glass of water and watch as the bird periodically dunks its head into the glass for a "drink."