Imagine you are walking down an isolated road out in the country. Far down the road you can see, and also hear, a vehicle fast approaching as the driver is using his horn without interruption. As the car gets closer, the frequency or pitch of the sound gets louder, but as it passes you and speeds farther away, the frequency or pitch immediately gets lower. You have just experienced a ______.
sonic shift
binary audition
frequency split
Doppler shift
