Students test a range of household liquids using a natural indicator made from red cabbage juice or turmeric, sorting them by their pH.
Tap a step to mark it as done.
Teach: acid, alkali, neutral, pH, indicator, neutralise, concentration. The colour change is dramatic and memorable — let students observe it for themselves before explaining.
Focus on the sort into acid/neutral/alkali without introducing the numerical pH scale.
Can students correctly classify five liquids as acidic, neutral, or alkaline? Can they describe what an indicator is and how it is used?
Red cabbage is cheap and widely available. Turmeric is even more accessible in many regions. Vinegar, water, and baking soda are all very low cost. No pH meter or litmus paper needed.
Students sometimes think acidic means dangerous. Many acidic substances are perfectly safe — lemon juice and vinegar are edible. The danger of some acids is about concentration, not acidity alone.
Acids and alkalis introduce the chemistry of reactions and the concept of pH. The natural indicator activity demonstrates that chemistry can be done with everyday materials.
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