Teacher sheet · Ages 10–11 · about 45–50 minutes
Ears: from a vibration to a signal in the brain
Lesson page: echoesof.science/school/ears/ages-10-11/ · Pupil worksheet: echoesof.science/school/ears/ages-10-11/print/
Learning aims
- Describe the path of sound through the outer, middle and inner ear.
- Explain that hair cells turn vibrations into electrical signals.
- Explain how two ears help locate a sound.
- Carry out a fair test and compare results.
- Know simple ways to protect hearing.
Lesson plan
| Time | Activity |
|---|---|
| 5 min | Starter: close your eyes; the teacher taps somewhere in the room. Point to it! |
| 10 min | Read the text with a diagram of the ear. |
| 20 min | Where is that sound? in groups of three (listener, tester, recorder). |
| 5 min | Compare class results: both ears versus one ear. |
| 5 min | Quiz or the Outer, middle or inner ear? game. |
Materials for the experiment
- Two pencils (to tap together)
- A chair in an open space
- A record sheet and a pencil
Safety: Tap softly and never close to anyone's ear. Cover the ear with a flat hand only: never put anything inside the ear. The listener stays seated.
Common misconceptions
| Pupils may think… | Actually… |
|---|---|
| The eardrum is what sends the signal to the brain. | The eardrum only vibrates; hair cells in the cochlea make the electrical signal. |
| Ears are only for hearing. | The inner ear also senses head turning, tilting and gravity. |
| If noise doesn't hurt, it can't damage hearing. | Long exposure to noise above about 85 dB can damage hair cells without pain. |
Worksheet answers
- Sound goes down the ear canal and makes the eardrum vibrate; the three bones amplify the vibrations; the fluid in the cochlea ripples; hair cells bend and make an electrical signal; the auditory nerve carries it to the brain.
- Class results; usually fewer correct with one ear covered.
- The brain compares the timing and loudness at both ears; with one ear covered that comparison is mostly lost.
- Any two of: move away from loud noise, wear ear protection, give ears a rest, keep headphones well below maximum volume.
Quiz answers
- What are the three small bones of the middle ear called? Malleus, incus and stapes. These three bones amplify the vibrations.[1]
- What is inside the cochlea? Fluid. The cochlea is filled with fluid that ripples.[1]
- Hair cells near the wide end of the cochlea detect… high-pitched sounds. Those near the centre detect low-pitched sounds.[1]
- How do two ears help you tell where a sound comes from? The brain compares when and how loudly it reaches each ear. Timing and loudness differences between the ears give the direction.[3]
- What do the semicircular canals do? Sense when your head turns. They are part of the balance system in the inner ear.[2]
- You have to raise your voice to be heard at arm's length. The noise is probably… above 85 dB. CDC uses this as a warning sign of possibly harmful noise.[5]
Going further
Repeat the test with sounds from directly in front and directly behind only. Is front versus behind harder than left versus right? Why might that be?
Sources used in this lesson
- [1] How Do We Hear? (National Institute on Deafness and Other Communication Disorders (NIDCD, NIH)): reliability High
- [2] Biology 2e, 36.4 Hearing and Vestibular Sensation (OpenStax, Rice University): reliability High
- [3] Psychology 2e, 5.4 Hearing (OpenStax, Rice University): reliability High
- [4] Sensation and Perception: Interaural Time Difference (University of Minnesota (open course text, PSY 3031)): reliability Medium-high
- [5] What Noises Cause Hearing Loss? (Centers for Disease Control and Prevention (CDC)): reliability High
- [6] Hearing and Hair Cells (Stanford Medicine, Ear Institute): reliability High
Full list with links and a note on each source's reliability: echoesof.science/school/ears/sources/
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