Answer:
sound pulse travels from a ship to the seafloor and back
Explanation:
An echo sounder employees techniques used in measuring the depth of the water body. Sound waves are usually passed from the ship into the sea and the time required for the waves to travel from the ship to the sea floor and back is usually recorded.
It is used in the calculation of the speed of sound in water at that point in time which varies according to the depth and physical characteristics of the water body involved.
