The students should learn how to apply and enlarge their chemical knowledge to explain “normal” procedures and products in use at home. The topic of cleaners has been chosen even though it might not be the most interesting one to 13/14-year-olds as it offers a variety of stimulating experiments the students can carry out themselves.
The sub-unit can begin with newspaper articles on accidents in the household and / or advertisements for household products such as detergents and cleaners. The students can be invited to develop and collect explanations in small groups choosing different stories or advertisements. To do so, they have to apply their knowledge on substances and reactions. They are also asked to write down questions for aspects they cannot explain.
Following this broader collection, the students can decide together with the teacher which specific topics they wish to investigate further. One area would be the investigation of different cleaners, regarding general properties (e.g. solubility, pH), and effects on different stains. The result should be a table of substances, properties and suggestions for use, combining results collected from different groups. The process of investigation should follow the IBSE steps, as exemplarily described in sub-unit 1