1. Get out your notes sheet from yesterday.
If you are in band: please place your instrument case beside your desk. We will be using them today. If you forgot it is okay and no, you may not get it.
Think- Pair-Share on this famous question with your neighbor: "If a tree falls in a forest and no one is around to hear it, does it make a sound?“ Explain your reasoning.

2. Definition: the organ humans use to detect sound.
The Human Ear
Definition: the organ humans use to detect sound.

3. The human ear is divided into three sections.

4. Each part of the ear serves a specific purpose in the task of detecting and interpreting sound.

5. The Outer Ear Picture a satellite dish that collects radio waves.
The outer ear is similar!
The curved formation on the outside ( the pinna) helps funnel sound down the ear canal to the eardrum.

6. How Sound Travels in the Middle Ear
When sound waves reach the middle ear, they cause the eardrum to vibrate.
This vibration then causes the three bones to vibrate.
These vibrations are transformed into longitudinal/pressure waves in the middle ear.

7. Bones of the Middle Ear These are the smallest bones in your body!
Together, they’re about the size of an orange seed.
Hammer
Anvil
Eardrum
Stirrup

8. The Stirrup (or stapes)

9. The Inner Ear
Two main parts:
Cochlea
Auditory Nerve

10. The Cochlea Coiled like a snail shell
Contains approximately 300,000 hair cells
Is filled with fluid, through which sound can travel easily.

11. Cochlear Hair Cells
These tiny hairs bend because of the vibrations caused by the sound waves.

12. Cochlear Hair Cells in Action

13. The Auditory Nerve
The tiny hair cells of the cochlea are set in motion by vibrations
The vibrations stimulate tiny nerve cells.
The nerve cells then send signals along the auditory nerve to the brain.

14. A sound is not actually heard until the brain receives and processes these signals.

15. How does the ear work? Sound waves are sent.
The outer ear “catches the sound waves”.
The middle ear takes the sound waves and “vibrates” the eardrum.
The inner ear sends the messages to the brain and helps with balance
Middle Ear
Outer Ear
Inner Ear
Sound Waves
The brain puts it together and hooray! You hear your favorite song on the radio.

16. D H E B A G C F Put the following steps in order:
The stirrup moves back and forth, creating pressure waves in the cochlea.
The bones of the middle ear (hammer, anvil, & stirrup) vibrate.
Hair cells send an electrical impulse through the auditory nerve.
The outer part of the ear (the pinna) "catches" the sound waves.
Sound waves vibrate the eardrum
The brain receives an electrical impulse and interprets it as sound.
Tiny hair cells in the cochlea move as the waves pass.
The sound waves travel into the ear canal. D H E B A G C F

17. Let’s start at the very beginning…
The Human Ear

18. https://wonderville.org/asset/how-we-hear

19. Band Instrument Wave Activity
Which instrument had the highest frequency?
Which had the lowest frequency?
Draw a high frequency wave. What is the pitch?
Draw a low frequency wave. What is the pitch?
Label a crest and a trough on a series of waves.
Label a wavelength on a series of waves.
Show a high amplitude wave. What is the volume?
Show a low amplitude wave. What is the volume?