Natural Resonance of Sound

Try this

Acquire a bottle with a small mouth that can easily resonate by blowing over it. Using the Tone Detector tool, record the resonating frequency produced by the bottle. Record the pitches produced in the bottle at various length (measured with a meter stick) modified by adding or removing water from the bottle. (It is also possible to study the physical properties of resonating rods, including their density/material, length, and Young’s Modulus value).

Challenge yourself

• Create a graph of Frequency vs. Length of the resonant column of air, and derive a mathematical expression for this relationship.
• If there are any constants in this mathematical expression, explain their significance.
• Try the experiment again, and do this instead with a resonating wine glass, using your wetted finger to make the glass resonate. (Note: In the case of wine glass resonance, it is the actual glass - not the column of air - that resonates). Consider how it might be appropriate to measure the variable in question. Try this with glasses of various shapes, sizes, and thicknesses.