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.
Johnny Galecki played the goofy David Healy, the boyfriend and, later, husband of Roseanneâs daughter Darlene. Now, Galecki is widely known for his role on The Big Bang Theory, on which he plays a dorky scientist Leonard Hofstadter. The actor is earning more than $US1 million per episode.