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.
List of Gravity Falls characters. The Disney Channel television series Gravity Falls made by Alex Hirsch features an extensive cast of characters. All of the characters listed have appeared in the [[List of Gravity Falls episodes|1st and 2nd seasons.