Singing Wine Glass Simulator (2D)

This cross-section view shows the physics behind a "singing" wine glass: a finger dragged around the rim excites a stick-slip friction cycle that pumps energy into the glass's natural hoop-mode resonance. Tune the rubbing speed to match the resonant pitch and watch the standing wave — an ellipse with four nodes — grow on the rim. The resonant frequency itself depends on the glass's size, wall thickness and how much water sits inside it: a thicker wall rings higher, a bigger bowl rings lower, and topping up the water always drops the pitch further by adding vibrating mass, exactly like the real trick used to "play" a set of glasses as an instrument. Its companion 3D model is the 3D Singing Wine Glass.