About This Lesson
where the time in the formula is how long it takes the sound to go to the sea bed and back.
There is a distinct difference between a sound pulse reflected from the sea bed and one reflected from a shoal of fish. The one reflected from the sea bed is distinct and not spread out in time while the one from the fish is more diffuse (woolly) and spread out as it reflects from fish at slightly different depths.
Moving objects like submarines and fish make the pitch of the reflected sound alter — this is called the Doppler Shift:
