Question

Harbor seals, like many animals, determine the direction from which a sound is coming by sensing the difference in arrival times at their two ears. A small difference in arrival times means that the object is in front of the seal; a larger difference means it is to the left or right. There is a minimum time difference that a seal can sense, and this leads to a limitation on a seal's direction sense. Seals can distinguish between two sounds that come from directions 3∘ apart in air, but this increases to 9∘ in water.Explain why you would expect a seal's directional discrimination to be worse in water than in air.

Answer 1

Answer:

that the angle must be increased to maintain the minimum time of discrimination due to the increase in the speed of sound in material

Explanation:

The direction of sound is detected by the difference in time of reception of each ear, the speed of the wave is

             v = d / t

             t = d / v

In air the velocity is v = 330 m / s, let's use trigonometry

           Cos 3 = d / L

           L = d / cos 3

The difference in distance is

            Δd = d - d / cos 3 = d (1- 1 / cos3)

             t = Δd / 330

When the animal is in the water the speed of sound is

              v = 1540 m / s

So time is

             t' = Δd ’/ 1540

            t ’= Dd’ / 4.67  330

So if  t = t’  is the minimum response time, the distance must be increased

            Δd ’= 4.6 Δd

            1-1 / cos θ = 4.6 (1- 1 / cos 3) = -4.6 0.00137 = -0.00631

           1 + 0.0063 = 1 / cos θ

           1.00631 = 1 / cos θ

           Cos θ = 1 / 1.00631

           Tea = 6.5

We see that the angle must be increased to maintain the minimum time of discrimination due to the increase in the speed of sound in material