Many different types of energy can be converted into heat energy. Light, electrical, mechanical, chemical, nuclear, sound and thermal energy itself can each cause a substance to heat up by increasing the speed of its molecules. So, put energy into a system and it heats up, take energy away and it cools.
Alexander Alex Robert Hirsch (born June 18, 1985) is the creator and former executive producer of the American animated television series, Gravity Falls. He voiced two of the main characters, Grunkle Stan and Soos. He also voiced supporting and recurring characters such as: Old Man McGucket, Bill Cipher, the gnomes and many others.
Played by: Zach Galligan. The Hero of the films, a young cartoonist who works in Kingston Falls' bank. Receiving Gizmo as a pet from his dad, Billy quickly learns to appreciate the Schmuck Bait for caring for him.