Aim: To understand methods of obtaining clean drinking water.
Stages:
Note: Distillation produces purer water but is too energy-intensive for large-scale use.
• Chlorine gas is toxic and irritating — only tiny, controlled amounts are used; add it in a fume cupboard/well-ventilated area and never inhale it.
• Raw river/pond water can carry pathogens — treat it as contaminated, wear gloves, and wash hands after handling.
• Never taste any water purified in a school lab — it is a model of the process, not certified drinking water.
• Sand, gravel and stone dust are irritants — avoid inhaling; handle glassware carefully.
• Too much chlorine makes water unsafe/unpleasant — correct dosing matters.
Lock a prediction before running the stages.