Imagine a moving boat making waves in the middle of a pool of water. Also, imagine two observers, one behind the boat and one in front of the boat. Describe how each observer will see the waves generated by the boat and explain their observations.

The person who is behind the boat will see much powerful and bigger waves than the person who is in front of the boat. This phenomenon is caused by the Doppler effect which describes the changes in the observed frequency of a wave whenever there is relative motion between the wave source and the observer.