Biology 11–12 · Year 12

Air and bone conduction: Rinne and Weber tests with a simulated conductive loss

Module 8: Non-infectious Disease and Disorders (Technologies and Disorders: hearing loss)

PracticalLow risk

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The idea

Sound reaches the inner ear through the air of the ear canal and middle ear or directly through the skull, and closing off the air route shows why a bone conduction implant helps conductive hearing loss while a cochlear implant is needed when the inner ear itself fails.

What you need

Tuning fork of 512 Hz, the frequency normally used for the Rinne test, one per group
Rubber striking pad or the heel of the hand; stop clock
Soft foam earplugs, one per participant (new, never shared), to simulate a plugged ear canal

How to do it

Weber test: strike the fork gently and place its base on the midline of the forehead; the participant says whether the sound is central or louder on one side.
Rinne test: place the base of the vibrating fork on the bone behind one ear until the participant can no longer hear it, then hold the prongs 1 to 2 cm from the ear canal and ask whether it can be heard again; time both stages.
Insert an earplug in one ear to simulate a conductive loss and repeat both tests.
Tabulate results for each ear with and without the earplug.
Explain why the plugged ear hears the Weber tone louder, and which technology (hearing aid, bone conduction implant, cochlear implant) suits a conductive and a sensorineural loss.

What you should see

With both ears open, the Weber tone is heard centrally and the Rinne test is positive: the fork is heard again beside the ear after bone conduction fades, because air conduction is more sensitive. With one ear plugged, the Weber tone lateralises to the plugged ear and the Rinne test on that side usually reverses, bone conduction lasting at least as long as air conduction: the pattern of a conductive loss (the StatPearls Weber chapter states that sound lateralises to the affected side in conductive loss). The learner knows it worked when the lateralisation moves to whichever ear is plugged.

What changes

What you change: ear canal open or plugged
What you measure: side where the Weber tone is heard; Rinne result and times
What you keep the same: same fork and striking force
placement points
quiet room

Common misconceptions

Each of these ideas is wrong, and the activity is a chance to test it.

All hearing loss is the same and a louder sound fixes it; a conductive loss and a sensorineural loss need different technologies.
Sound only reaches the inner ear through the ear canal; the skull carries it too, which is how bone conduction implants work.
A cochlear implant amplifies sound; it stimulates the auditory nerve electrically when hair cells no longer work.

Safety card

Low riskLearners carry it out

Hazards

Striking the fork too hard close to the ear
Shared earplugs

Controls

Strike gently on the rubber pad away from the head
New earplugs for each person, inserted only as far as the packet directs

Note

Learners are participants: participation is voluntary, anyone may opt out or withdraw their data, and results are recorded without names, following the briefing and consent approach in the practicalbiology.org human-subject protocols. This is a demonstration, not a hearing test; anyone with concerns about their hearing is referred to a doctor or audiologist.

Curriculum references

The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.

Biology Stage 6 Syllabus (2017), current: Year 11 taught to the end of 2026 and Year 12 to Term 3 2027BIO12-15 BIO11/12-7
Australian Curriculum v9No Australian Curriculum v9 code is listed.

Sources

The pages the author read to write this activity.

All Concept Studio activities