Understanding the Human Ear's Sensitivity to 3500Hz Sounds

[rizardon]

Homework Statement

The auditory canal of the human ear extends about 2.5 cm from the outside ear to the eardrum
(a)Explain why the human ear is especially sensitive to sounds at frequencies around 3500Hz.

Homework Equations

Speed of sound v=344m/s

The Attempt at a Solution

I know the human can hear sound with frequency between 500Hz-3500Hz,but , I don't how to explain how and why we hear what we hear. It would be great if anyone could give me some clues.

 

[Tusike]

I'm not exactly sure about this, but it gives the right solution, so I'll tell it anyway:)
The ear can be thought of as a pipe with one end open, the other closed. This means that resonance of the sound waves can happen every s=(2k+1)*lambda / 4 distances, where s is the length of the pipe. Now, substitute s = 0.025m and k=0, we get that lambda = 0.1m, and since f=c/lambda, f = 3440Hz. So because of the resonance, we would be especially sensitive to frequencies near that. (For k>0, we get frequencies so high that the human can't sense. Btw, I think we're ranged from 100Hz to 4000Hz, although I'm not sure of the lower boundry).

 

[rl.bhat]

Ear is sensitive for the frequency which forms anti node at the opening of the ear and node at the ear drum. Length of the auditory canal is 2.5 cm. So the wavelength of the frequency is 4*2.5 cm.
Now velocity v = f*lambda.
Find f.

 

[Bartek]

I know the human can hear sound with frequency between 500Hz-3500Hz,but , I don't how to explain how and why we hear what we hear. It would be great if anyone could give me some clues.

We can hear sound with frequency between 16Hz and 20000Hz!

Sound is a traveling wave which is an oscillation of pressure transmitted through an air. When that wave reaches eardrum, the eardrum begins to vibrate. We interpret this vibrations as a sound. No matter how - it is biology.

Imagine auditory canal as a pipe with eardrum at the one end and open at the second. You should calculate which is frequency of standing (stationary) sound wave in that pipe. Wave with that frequency will be strengthened.

 

[rwisz]

I can provide a few possible explanations for why the human ear is particularly sensitive to sounds at frequencies around 3500Hz.

1. Resonance: The human ear is a complex and delicate organ that is designed to detect and process sound waves. It has a natural resonance frequency, which is the frequency at which it vibrates most easily. The ear's resonance frequency is around 3500Hz, which means that it is able to detect and amplify sounds at this frequency more efficiently than others.

2. Anatomy: The anatomy of the human ear, specifically the shape and size of the auditory canal, also contributes to its sensitivity to sounds at 3500Hz. The auditory canal is a narrow, curved tube that leads to the eardrum. This shape and length are optimal for amplifying sounds at frequencies around 3500Hz, making them easier to detect by the ear.

3. Evolution: The human ear has evolved over millions of years to be sensitive to sounds that are most relevant to our survival. Frequencies around 3500Hz are common in nature, such as the sounds of human speech, animal vocalizations, and environmental sounds like rustling leaves. Therefore, our ears have become particularly attuned to these frequencies in order to help us communicate and be aware of potential threats.

Ultimately, the sensitivity of the human ear to sounds at 3500Hz is likely a combination of all these factors and possibly others that we have yet to fully understand. Our ears are complex and amazing organs that have evolved to help us navigate and interact with our environment through sound.