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Hearing Lab 2
Calculating the Area and Lever Benefits of the Middle Ear
To the Instructor: This gives your students an opportunity to use their newly found abilities to
work with the decibel and to verify how the information on the benefits was acquired. This is
best done in small groups. It’s a good idea to remind students to bring their calculators
(especially those who have calculators with logarithm functions).
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Name: _______________________________________ Course: _______________________
Hearing Lab 2
Calculating the Area and Lever Benefits of the Middle Ear
You already know the critical details of the lever and area benefits of the middle ear. Now all
you have to do is plug the numbers into the decibel equation to see what that real-world gain is.
1. Area benefit:
Given
Tympanic membrane = 55 mm2
Oval window = 3 mm2
Ratio = 55:3
Find benefit in dB:
2. Lever benefit:
Given
Malleus = 9 mm long
Incus = 7 mm long
Ratio = 9:7
Find benefit in dB:
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ANSWER KEY
To the Instructor:
1. Area benefit:
Given
Tympanic membrane = 55 mm2
Oval window = 3 mm2
Ratio = 55:3
2. Lever benefit:
Given
Malleus = 9 mm long
Incus = 7 mm long
Ratio = 9:7
Find benefit in dB: