Circadian Rhythm 2D — Phase Clock & Entrainment Simulator

Light schedule

Light–dark cycle

Light onset (local time): 7:00 Light duration: 16 h

Simulation

Time speed: 4 h/s

Live state

Biological time—

Local (environment) time—

Phase difference—

Drift rate—

Simulated day—

—

Model
Internal phase free-runs at τ ≈ 24.3 h. When the light–dark cycle is on, light shifts the clock through a stylized phase-response curve (PRC): light after the internal temperature minimum (biological early morning) advances the clock; light before it (biological evening/night) delays it — a dead zone sits around biological midday. No light ⇒ free-running drift only.