1 “Wait a minute—didn’t the double-slit experiment prove that light is a wave?!?” This is one of the many times where the bizarreness of the atomic world emerges. Yes, light does behave like a wave. But light behaves like a particle also, as we see later in this chapter. It’s not that light is a wave some of the time and a particle the rest of the time; rather, light is simply light all the time, and some of its properties are wave-like and some are particle-like.