AQA A-Level Physics: Simple Structure of the Ear and Transmission Processes — mark scheme explained

The question

Label the parts of the ear in the diagram below: [Diagram with unlabelled parts] [Paraphrased for study — not reproduced from any exam paper.]

Mark scheme, decoded

What each mark is really for — in plain English — and the wording trap that loses it.

• S1

  Identify the visible part of the ear (pinna).

• S2

  Locate the external auditory canal, which leads to the eardrum.

• S3

  Find the three small bones in the middle ear (malleus, incus, and stapes).

• S4

  Label the oval window where vibrations are transmitted to the cochlea.

• S5

  Identify the cochlea in the inner ear, containing fluid and hair cells.

Model answer

Worked through, with each step tagged to the mark it earns.

1. S1

   Identify the visible part of the ear (pinna).

2. S2

   Locate the external auditory canal, which leads to the eardrum.

3. S3

   Find the three small bones in the middle ear (malleus, incus, and stapes).

4. S4

   Label the oval window where vibrations are transmitted to the cochlea.

5. S5

   Identify the cochlea in the inner ear, containing fluid and hair cells.

6. Final answer: [Diagram with correctly labelled parts]

Common mistakes

• Confusing the pinna with the eardrum — Remember that the pinna is the external part you can see, and it collects sound waves. The eardrum is inside the ear canal and vibrates in response to sound waves.
• Forgetting the amplification role of the ossicles — Always mention that the ossicles amplify the vibrations from the eardrum, making them strong enough to move the fluid in the cochlea.
• Misidentifying the parts of the middle ear — Practice identifying each ossicle by name and function. The malleus is attached to the eardrum, the incus connects the malleus to the stapes, and the stapes transmits vibrations to the oval window.
• Not understanding the role of hair cells — Focus on how hair cells bend in response to fluid movement, generating action potentials that are sent to the brain via the auditory nerve.
• Confusing the basilar membrane with the oval window — Remember that the oval window is where vibrations from the stapes are transmitted to the cochlea, while the basilar membrane supports hair cells and moves in response to fluid waves.
• Forgetting the role of the auditory nerve — Always mention that electrical signals generated by hair cells are sent to the brain via the auditory nerve for interpretation as sound.

Where the marks go

• Full worked solution (all marking points)5 marks

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