Suppose you have two stopped watches and both are set to noon. At noon you start your first
watch, and then you start your second watch 1 hour later. The second watch is 1 hour behind
the first watch. As time goes by, your second watch will continue to be 1 hour behind. Both
watches will maintain a 24-hour day, but they are out of synch with each other. Waves that are
out of phase behave similarly. Two waves that are out of phase are essentially two waves that
have been started at two different times. Both waves will complete full 360-degree cycles, but
they will do it out of phase, or out of synch with each other.