Question 23M.3.HL.TZ1.5
| Date | May 2023 | Marks available | [Maximum mark: 6] | Reference code | 23M.3.HL.TZ1.5 |
| Level | HL | Paper | 3 | Time zone | TZ1 |
| Command term | Explain, Identify, State | Question number | 5 | Adapted from | N/A |
The diagram shows a section through the ear.
Identify structures X and Y.
X: ...............................................................................................................................
Y: ...............................................................................................................................
[2]
X: ear drum/tympanic membrane;
Y: auditory nerve;
Y: Accept acoustic or cochlear nerve
This was an easy question and many were able to correctly identify one or both structures in the ear.
State how sound waves are changed by bones in the middle ear.
[1]
they are amplified / increase the force/strength of vibrations;
Many struggled to indicate what the bones in the middle ear did to sound waves, often simply rewording the question.
The graph shows the distance from the apex of the cochlea to the region where
different frequencies of sound wave are interpreted.
[Source: Bell, A., 2012. A Resonance Approach to Cochlear Mechanics. PLOS ONE [e-journal]. https://doi.org/10.1371/journal.
pone.0047918. Open Access.]
Explain how high frequency and low frequency sounds are distinguished.
[3]
- sound waves cause movement of the fluid in the inner ear/cochlea;
- this causes hair cells/sensory hairs in the cochlea to move;
- low frequency sounds would travel further into the cochlea/more towards apex than high frequency sounds;
- impulses are sent from different hair cells/sensory hairs according to their frequency;
- the brain interprets these as different sounds;
Accept vice versa.
This question was poorly done by the majority of candidates. Often, only one mark was awarded which came from the graph itself. The role of the cochlea did not seem to be understood.
