Every movement, however free it looks, has a pulse. A step, a swing of the arm, a beat of a wing — each repeats, and each repetition takes time.This session gives you the ...
A period (T) is the time it takes for one complete cycle of a repeating motion — one full step, one full wingbeat, one full swing.Frequency (f) is simply how many of those...
The simplest periodic body in physics is the pendulum: a weight swinging from a fixed point.Its period depends only on its length and on gravity — not on how wide it swing...
The most intimate periodic motion you own is your own heart: roughly one beat per second at rest — about 60-80 beats per minute, close to 1 Hz.Under exertion — danci...
Walking is periodic too: dancers and gait researchers alike call its frequency cadence — steps per minute. A relaxed walk sits around 100-120 steps/min, roughly 1.7-2 Hz.B...
Speed is frequency multiplied by how far each cycle carries you — its amplitude, or in gait terms, the stride length.Sprinters increase both: a faster leg-cycle frequency ...
Remember the pendulum: a longer pendulum swings more slowly. The same logic applies to limbs and wings, which behave like pendulums built out of muscle and bone.A short limb (or...
A hummingbird's wings beat around 50 times per second (50 Hz) — fast enough to hover motionless in the air.A housefly's wings beat even faster, well above 150-200 Hz &mdas...
A piano string is, again, a pendulum in disguise — just a vibrating one instead of a swinging one.Short, thin, tightly-strung strings (the piano's high notes) vibrate at a...
Music names the same quantity differently: tempo, measured in beats per minute (BPM).A tempo of 120 BPM means one beat every 0.5 seconds — a period of half a second, a fre...
Entrainment is what happens when an independent periodic body — a footstep, a heartbeat, a swinging arm — locks its own frequency onto an external one, such as a mus...
Measuring a heartbeat or a pendulum is easy. Measuring a dancer's full-body period, in real time, on stage, is not — which is exactly the technical problem this course is ...
Once a movement's frequency is captured as a number, it can be mapped — frequency to pitch, amplitude to volume, period to rhythm — onto a piano, real or sampled.Thi...
Today's vocabulary — period, frequency, amplitude, speed, entrainment — is the physical foundation for everything that follows in this course.Next sessions will get ...
