What it is
Sound is a pressure wave; music is sound organised in time. Pitch is frequency, loudness is amplitude and timbre is the mix of overtones that makes a violin sound unlike a voice.
Harmony has a mathematical core. An octave doubles the frequency, a perfect fifth multiplies it by 3/2, and the ancient Pythagoreans built a philosophy on such simple ratios.
Why some notes agree
Compares waves in simple frequency ratios (2:1, 3:2, 4:3) with a dissonant one.
Source: Stanford Encyclopedia of Philosophy
A model to explain the idea; not drawn to scale.
Ideas to carry
- 1
Ratios make harmony
Notes whose frequencies form simple ratios tend to sound consonant together.
- 2
Rhythm moves bodies
People sync movement to a beat almost without trying.
- 3
Silence is structure
The rests shape music as much as the notes.
Established What we know
Interpretation The older lens · Hinduism and Renaissance cosmology
Om is chanted as the first sound in Hindu tradition; Kepler’s Harmonices Mundi heard the planets as a choir.
Reading
- 6th century BCEThe monochord and harmonic ratiosPythagorean tradition
- 1619Harmonices MundiJohannes Kepler
- 1863On the Sensations of ToneHermann von Helmholtz
Physics: it is just vibrating air
My favourite song: makes me cry anyway
Connected subjects, projects and writing
- MathematicsSubject · Cosmos
Established Consonant intervals correspond to simple frequency ratios.
- DesignSubject · Creation
Architecture, image and interface: shaping things so people understand and enjoy them.
Sources
- Pythagoreanism Stanford Encyclopedia of Philosophy. Checked 5 Nov 2026.
- Noise-Induced Hearing Loss NIDCD (US National Institutes of Health). Checked 5 Nov 2026.