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Iodine Clock Reaction

Interactive 3D iodine clock reaction: tune reactant concentrations and temperature, watch a well-mixed solution stay colorless for a precisely predictable induction time, then flip to blue-black in an instant — a live demonstration of rate laws, reaction order, and the Arrhenius equation.

Chemistry & Materials3DModerate60 FPS📱 Mobile-adapted⇄ 2D version

The iodine clock reaction is a textbook demonstration of chemical kinetics: two reactions run simultaneously in the same flask, one slow (the iodide–persulfate redox step) and one fast (a thiosulfate scavenger that mops up the product as fast as it forms). While the scavenger lasts, the solution looks completely unchanged — then, the instant it is used up, the whole flask flips to deep blue-black at once as iodine finally builds up and binds starch indicator. This simulator renders that flask in 3D with thousands of instanced particles, integrates the real rate law and Arrhenius temperature dependence live, and lets you tune iodide, persulfate and scavenger concentrations plus temperature to see exactly how each one controls the induction time before the colour change.

⚙ Under the hood

Watch the classic persulfate–iodide clock reaction in 3D: tune reactant concentrations and temperature and see a colorless solution flip to blue-black at a precisely predictable induction time governed by the real rate law and the Arrhenius equation.

chemical kineticsrate lawArrhenius equationreaction orderactivation energy

3D · Three.js / WebGL renderer · 60 FPS target · runs fully client-side, no install