Build vibrating strings and air columns, tune resonances and connect the physical motion to oscilloscope measurements. Start with a prepared investigation or assemble your own apparatus.
What you can investigate
- Editable strings, drivers, supports and air columns
- Resonance, damping, plucked strings and harmonic spectra
- Pressure and displacement in open and closed tubes
- Microphone scans, oscilloscope cursors and measured frequency
- Pulse reflection at fixed, free and absorbing ends
- Captured measurements, fitted graphs and saved experiments
How does string length affect its resonant frequency?
- Find the first harmonic of a 1.00 m string at fixed tension and mass per unit length. Use Steady response to compare settled traces and capture a reading.
- Shorten the string to 0.80 m and then 0.50 m. Retune the driver to the first harmonic each time and capture the measured frequencies.
- In the notebook, plot measured frequency against 1 / length. Explain why this relationship follows from wave speed and the fixed-end boundary conditions.
A fixed string fits half a wavelength in its first harmonic. With unchanged tension and mass per unit length, wave speed is constant, so resonant frequency is inversely proportional to length.
Interpreting the model
The lab uses 16 damped modes with ideal supports and ideal open or closed tube ends. End correction is omitted. Particle motion is enlarged and slowed, while scope time remains in physical milliseconds. The virtual microphone measures pressure and the string pickup measures displacement. Listen is a sonification, not a calibrated acoustic radiation model.
Revision and practice