Two liquids both look clear. Which measurement would put them in order? Read an approximate pH, rank three solutions and distinguish an estimate from an exact measurement.

Pupils try “Rank coded solutions by pH”. Includes the editable PowerPoint, a 50-minute lesson plan and a printable pupil sheet with equipment, instructions, example evidence and worked teacher answers.

KS3 chemistry for ages 11–14. Part of the acids and alkalis sequence.