Chem Careers - Environmental Chemist, Universal Indicator Lesson

A lesson aimed at Year 7 -8 pupils with a split focus on learning the colour of Universal Indicator at different pHs and the role of an environmental chemist. Pupils imagine they are environmental chemists working for Scottish Water, responding to reports of dead fish being discovered in a loch.
Scottish water has some nice little animations that help demonstrate the role of environmental chemists: https://www.youtube.com/watch?v=AWLYN1MmnQE . In the first part of the lesson you will need to provide pupils with clearly labeled solutions of strong and weak acids and alkalis, plus a neutral solution (I usually use bench or 1M hydrochloric, ethanoic, water, ammonia and sodium hydroxide). Pupils combine these in spotting tiles with universal indicator solution to determine the different colours at different pH. You can then share and self mark their findings. In the second part of the lesson provide pupils with water samples taken from sites A to D. A and B should contain no lead and be only slightly acidic, C should be more acidic and contain lead nitrate solution (lead and acid are common contaminants from copper extraction). I usually make D contain slightly less lead and slightly less acidic (it is nice to discuss with pupils why this might be the case/dilution). Pupils test with potassium iodide (for lead) and Universal Indicator.
In a 1hr/50min lesson there should just be time to summarise the lesson’s learning and share conclusions.
Extension challenge for early finishers also included.