Man there is physics everywhere you look even in boating. When you are on a boat you see the waves that are created by the motor of the boat. these waves are transverse because they are moving one way while the waves are traveling perpendicular to the direction of the boat. When the water is at its highest point it is called a crest and when the wave of the water is at its lowest point it is called a trough. The frequency is the amount of waves that pass through during a certain time. Also there is a Doppler effect too. if you were just floating in the water and I came by in my boat the frequency of the sound would increase as I got closer and decrease as I got farther.