Conceptual

Everyday Coffee-Cup Physics Demonstrations Across Optics Acoustics and Fluids

A single coffee cup can demonstrate a surprising range of physics: optical caustics from curved reflecting surfaces, lifting of degenerate acoustic modes in a cavity, the temperature-dependent hot-chocolate pitch effect, the tea-leaf paradox driven by secondary flow, double-diffusive convection, and the evaporation-driven coffee-ring stain. Each phenomenon is paired with a low-cost experiment and a minimal quantitative model, making it a unified teaching resource that connects optics, acoustics, and fluid mechanics.