This weekend, we'll lose an hour of sleep but gain an hour of sunlight as Daylight Savings kicks in, all on the assumption that energy will be saved. Benjamin Franklin, America's practical founding father, thought daylight savings time would save energy. That was the rationale used in World Wars I and II, and the reason we'll be changing the clocks at 2 am this coming Sunday. Was Franklin right? Ryan Kellogg, Professor of Economics at University of Michigan, has a surprising answer.