Waves & Sound
Rich timbre (harmonics)
Press Play — compare a pure tone vs harmonic partials on the oscilloscope.
Rich timbre (harmonics) — interactive Waves & Sound simulation. Press Play — compare a pure tone vs harmonic partials on the oscilloscope. Free browser-based virtual physics lab with live SI measurements and a guided tutorial.
Timbre and harmonics
Real instruments produce a fundamental plus overtones. The mix of harmonics sets the timbre.
A Fourier series of sine waves at integer multiples of the fundamental builds complex wave shapes. Different harmonic weights change the sound character.
- Fundamental + overtones
- Timbre = harmonic mix
Investigation brief
Plan the question before you open the lab
The brief mirrors the prerendered page: driving question, competing predictions, variable roles, governing laws, setup, analysis and extension prompts remain visible and in this order.
Driving question
A musical tone at 220 Hz sounds different from a pure sine wave at 220 Hz — it has 'color' or timbre. What's actually different about its sound wave?
Predictions to weigh
- The tone is just a louder version of the same pure 220 Hz wave.
- The tone has a different fundamental pitch than 220 Hz.
- The tone is a mix of the fundamental plus higher harmonics at different strengths.
Variable roles
What you set:
- Harmonic number n
What you measure:
- Frequency n·220 Hz
- Amplitude ratio (vs. fundamental)
How the investigation runs
- Open the rich-timbre preset and press Reset. The source emits a 220 Hz fundamental blended with specific higher harmonics.
- Enable the harmonic spectrum display at the observer.
- For each row, read off the amplitude of the listed harmonic relative to the fundamental's amplitude.
What the printable worksheet asks students to work out
- List the frequency of each harmonic in your table as n × 220 Hz, and compare your recorded amplitude ratios to the spectrum display.
- The 2nd and 4th harmonics have zero amplitude in this tone, while the 1st, 3rd, and 5th (all odd) are present. What does a spectrum with only odd harmonics tell you about the shape of the wave?
Where this shows up beyond the lab
- A clarinet's tone is dominated by odd harmonics, similar to this one, while a violin's tone includes strong even harmonics too. Explain why two instruments playing the identical fundamental pitch (220 Hz) still sound completely different.
- A tuning fork produces a nearly pure tone (only the fundamental, no higher harmonics). How would its spectrum bar chart look different from this experiment's?
- AP Physics 2 — Unit 14: Waves, Sound, and Physical Optics
- IB Physics — C.3 Wave phenomena
- General High School Physics — Waves & sound
- NGSS High School Physics — Wave properties
- Welcome to Rich Timbre
- Select the source
- Press Play
- Harmonic recipe
- Open the Properties panel
- You did it!
Open the interactive simulation to build the scene, press Play, and explore with live measurements and a guided tutorial.