How Ears Detect Sound

Name:

Date:

📚 Part 1: Multiple Choice

1. Which part of the ear collects sound waves from the environment?

Eardrum

Outer ear

Cochlea

Inner ear

2. What happens when sound waves hit the eardrum?

It sends signals directly to the brain

It vibrates back and forth

It amplifies the sound waves

It filters out unwanted noise

3. Which tiny bones are found in the middle ear? (Check all that apply)

Hammer (malleus)

Anvil (incus)

Stirrup (stapes)

Cochlea

4. The cochlea is filled with:

Air

Fluid

Tiny bones

Nerve tissue

5. Hair cells in the cochlea convert sound vibrations into:

Louder sounds

Electrical signals

Heat energy

Light waves

✏️ Part 2: Short Answer Questions

6. Describe the path that sound takes from entering your ear to being interpreted by your brain. Use the following terms: outer ear, eardrum, middle ear bones, cochlea, auditory nerve, brain.

7. Explain why the three tiny bones in the middle ear are important for hearing.

8. What would happen to your hearing if the hair cells in your cochlea were damaged? Explain your reasoning.

🎨 Part 3: Diagram Labeling

9. In the space below, draw and label a simple diagram of the human ear. Include these parts: outer ear, ear canal, eardrum, hammer, anvil, stirrup, cochlea, and auditory nerve.

10. Fill in the blanks to complete the sequence of hearing:

Sound waves → _____________ → Eardrum vibrates → _____________ amplify vibrations → Cochlea converts vibrations to _____________ → _____________ carries signals to brain → Brain interprets sound

🔑 Answer Key

Part 1: Multiple Choice Answers

1. Outer ear - The outer ear (pinna) collects and funnels sound waves into the ear canal.

2. It vibrates back and forth - The eardrum vibrates when sound waves strike it, transferring the energy to the middle ear bones.

3. Hammer (malleus), Anvil (incus), Stirrup (stapes) - These are the three tiny bones in the middle ear. The cochlea is part of the inner ear.

4. Fluid - The cochlea is filled with fluid that helps transmit vibrations to the hair cells.

5. Electrical signals - Hair cells convert mechanical vibrations into electrical signals that the brain can interpret.

Part 2: Short Answer Sample Answers

6. Sound waves enter the outer ear and travel through the ear canal to the eardrum. The eardrum vibrates and moves the middle ear bones (hammer, anvil, stirrup), which amplify the vibrations. These vibrations enter the fluid-filled cochlea, where hair cells convert them into electrical signals. The auditory nerve carries these signals to the brain, where they are interpreted as sound.

7. The three tiny bones (hammer, anvil, stirrup) amplify sound vibrations from the eardrum and transfer them efficiently to the inner ear. They act like a lever system that increases the force of vibrations, making quiet sounds loud enough for the inner ear to detect.

8. If hair cells in the cochlea were damaged, hearing would be impaired or lost. Hair cells are responsible for converting sound vibrations into electrical signals. Damaged hair cells cannot regenerate in humans, so this would result in permanent hearing loss for the frequencies those particular hair cells were responsible for detecting.

Part 3: Diagram and Fill-in-the-Blank Answers

9. Diagram should include: outer ear (pinna), ear canal, eardrum, hammer, anvil, stirrup, cochlea, and auditory nerve, with proper positioning showing the path from outer to inner ear.

10. Sound waves → Outer ear/ear canal → Eardrum vibrates → Middle ear bones amplify vibrations → Cochlea converts vibrations to electrical signals → Auditory nerve carries signals to brain → Brain interprets sound