Day 1: And There Was Sound, Part 1
Anatomy and Physiology of the Auditory System
Objective: Know the anatomy and physiology of the auditory system.
- As an attention step, show a video clip of sound traveling through the auditory system with the sound turned down. Ask the students what the video was about. Do they know the different parts? OR simply ask rhetorical questions regarding how the ear works. I.e., what’s the middle, outer, inner ear? How do they work?
- Explain the model of the ear. Then, line 5 students up in front of the classroom close enough together that they touch when swaying. Explain that each student will pretend to be a part of the auditory system: outer ear, middle ear, cochlea or inner ear, hearing nerve, and brain. Have remainder of students make noise. Touch the first student in line to get the sound started on it’s way through the “ear”. Next, demonstrate conductive, sensorineural, and central hearing losses by removing a “part” of the ear from the demonstration. Continue having the class make noise for each demonstration. Students can be seated at the end of the demonstration. To demonstrate how the inner ear works, that student may hold and wiggle spaghetti noodles (see attached lesson plan) or “animal making” balloons.
- Next, focus on noise-induced hearing loss and the hair cells inside the cochlea using spaghetti placed in a lump of Play-doh. The spaghetti will demonstrate the flexibility and function of the hair cells. Also, it will show how hair cells can be destroyed from repeated exposure to noise. Generate a soft noise slightly bend the spaghetti. Increase the loudness of the sound and gradually put more pressure on the spaghetti. When the sound gets extremely loud, the spaghetti should break. [see attached lesson plan]
- Use balloons to represent hair cells. Have students generate noise. When it gets too loud, pop some balloons to show hair cells being destroyed by too much hazardous noise.
- Transition to next topic or summarize and close as appropriate.
- Model of ear
- 5 students
- Noise source
- A&P Video
Spaghetti and Clay/Playdough Demonstration
The purpose of this exercise is to visually demonstrate how the anatomical structures of the ear become permanently damaged by excessive noise exposure. Within the inner ear lies the cochlea and within the cochlea is the Organ of Corti. The Organ of Corti contains the tiny hair cells that become permanently damaged by noise. The uncooked spaghetti represents the hair cells within the organ of Corti. The clay or Playdough represents the tectoral membrane on which the hair cells reside.
- In the palm of your hand, place a flattened piece of clay/Playdough approximately 2 x 3 inches square and approximately 1/2 inch thick.
- Insert a small handful (approximately 10 full-length pieces) of uncooked spaghetti into the clay/Playdough so that the spaghetti stands upright without assistance. Be sure the top ends of the spaghetti are even in length.
- Begin talking at a soft volume level.
- With your free hand, gently press the top ends of the spaghetti into your palm.
- With a gently swaying motion, make the spaghetti bow from side to side in rhythm with your soft voice.
- Say to the children,”When the sound is soft, little hairs way inside your ear sway back and forth like this. It is these little hairs that allow you to hear. If you do not have these little hairs, you cannot hear”.
- Start talking louder.
- Make the spaghetti bow with slightly greater vigor but without breaking the spaghetti. Tell the children, “When the sound gets louder, the little hairs move more”.
- Start talking very loud.
- Make the spaghetti bow and then break. Tell the children, “what happened to my little hairs inside my ear?” Allow the children to tell you what they think happened to the hairs. Then say, “When the sound gets so loud, the little hairs break. But that’s okay, the little hair will grow back, right?” Allow the children to give their responses and then tell them, “Once those little hairs are broken, they don’t grow back and your hearing is damaged forever.”
- Allow for some dialogue to follow as the children have questions about the demonstration.