Physical Principles

Entries

• EntropyEntropy is often introduced as “disorder,” but that metaphor fails surprisingly quickly. The more useful statistical idea is multiplicity: how many microscopic arrangements correspond to the same macroscopic state.
• Why Ice Is SlipperyIce is slippery because the contact between a solid slider and ice is not simply dry solidonsolid friction. Near the melting point, the surface has enhanced molecular mobility, and sliding can create or thicken a thin lubricating layer through frictional heating and interfacial disorder.
• Galileo Thermometer: Temperature Read Through BuoyancyA Galileo thermometer looks like a sealed glass column containing several floating glass bulbs, each carrying a temperature tag.
• Double Pendulum: Two Simple Joints, Nonlinear MotionA simple pendulum already has nonlinear dynamics at large angles.
• Chaos: Sensitive Dependence Without RandomnessIn ordinary speech, "chaos" means disorder.