Which has more energy -- a laptop battery or a hand grenade? A pound of cookies or a pound of gasoline? A fastball or a bullet? How high could a Double-A battery lift you? How many solar panels would it take to run a toaster, or a cell phone, or a city? If a bird caught a mosquito made of antimatter outside your building, would you survive the explosion? If you blew up the Moon, what would happen to the Earth? This class will discuss what energy is, how to tell how much of it there is, and how to figure out what it can do. We'll discuss different power sources and how to compare them, from cell phone batteries to nuclear power plants. Throughout the discussion, we will focus on getting fast answers to real-world physics questions using basic math, a piece of scratch paper, and Google Calculator.