Required practical: Neutralisation (Titration)
What the simulation does
It is a 3D interactive titration bench for the AQA GCSE required practical on neutralisation (neutralization). Pupils pipette 25.0 cm³ of sodium hydroxide of unknown concentration into a conical flask, add phenolphthalein so the solution turns pink, and fill a burette with hydrochloric acid of known concentration (0.100 mol/dm³). Clicking the tap runs acid into the flask, which swirls to mix, and the tap closes itself the moment the pink permanently disappears at the end point. Pupils do a rough run first, then repeat accurate runs until they have two concordant titres within 0.10 cm³, and the simulation records each titre as final reading minus initial reading. It then works through the full calculation to find the concentration of the alkali. A full accessibility suite is built in, including a dark theme, colour overlays, text scaling, shape coded cues, and a buttons only mode.
Suggested class activity (about 40 minutes)
Frame it as a lab challenge. In pairs, pupils run one rough titration and then keep going until they reach two concordant results, recording every burette reading in their own results table on paper as they go rather than relying on the screen. Once concordant, they pause before pressing calculate and work out the concentration by hand, then reveal the simulation’s answer to check. To stretch them, ask each pair to explain why the rough titre is discarded, why swirling matters, and what would happen to the calculated concentration if a pupil consistently overshot the end point. Finish with a quick whole class comparison of results and a discussion of why concordant repeats make the final value more reliable.