NOAA: “A favorite American pastime in fall is to pack a picnic basket and set off with loved ones on a Sunday drive along one of the nation’s many scenic byways. It’s a time of year when people enjoy crisp cool weather and marvel at the transforming landscape as tree leaves turn from lush green to gorgeous shades of yellow, orange, red, purple and brown. While we relish the opportunity to frolic in a big pile of freshly raked leaves, we don’t often think about the science behind why leaves change color and eventually fall from their branches. The answer may surprise you!“