THE+EAR+AND+HEARING

Back to IB PHYSICS > MEDICAL PHYSICS =THE EAR AND HEARING=

Describe the basic structure of the human ear. The structure should be limited to those features affecting the physical operation of the ear.

[|SIMULATION OF EAR]

State and explain how sound pressure variations in air are changed into larger pressure variations in the cochlear fluid. This can be dealt with in terms of the different areas of the eardrum and oval window, together with the lever action of the ossicles. Although the concept of impedance matching is not formally required, students should appreciate that, without a mechanism for pressure transformation between media of different densities (air and fluid), most sound would be reflected, rather than transmitted into the cochlear fluid. State the range of audible frequencies experienced by a person with normal hearing.

State and explain that a change in observed loudness is the response of the ear to a change in intensity.

State and explain that there is a logarithmic response of the ear to intensity.

Define //intensity// and also //intensity level// (//IL//).

State the approximate magnitude of the intensity level at which discomfort is experienced by a person with normal hearing.

Solve problems involving intensity levels.

Describe the effects on hearing of short-term and long-term exposure to noise.

Analyse and give a simple interpretation of graphs where IL is plotted against the logarithm of frequency for normal and for defective hearing.

Students should be aware of temporary and permanent deafness, tinnitus and selective frequency losses. They should show an appreciation of the social implications of hearing loss on an individual. **Aim 8:** Legislation and the moral responsibility of employers could be considered.