1. Helmholtz Resonators

2. Bottle Band

3. More examples: Whistling Jar
Pre-Columbian Whistling Jar
Basic Principle of Operation
(brief description of construction and cultural usage)
(1 min demo of natural sounds)
Image from:
Image from:

4. Yet more examples: The Ocarina
Ocarinas
Basic Principle of Operation

5. Spring Mass System in Disguise
Air plug in neck “bobs” in a big sea of air molecules

6. Resonant Frequency vsound velocity of sound waves in air
L length of plug of air in neck
S neck cross-section
V chamber volume of air

7. Assumptions…you know what they say
Which variable(s) is changing among these Coke bottles?
How do these Coke bottles compare to the simple physics model?
How would you determine S, L, and V?

8. Lab Experiment Tune bottles Compare actual frequency to theory
Do better than these guys!

9. Resources Univ of New South Wales Acoustical Physics group:
Eric Heller’s “Why you hear what you hear” chapter 13:
Mountain Ocarinas:
The Bottle Boys website: