Planning an investigation to prove the reactants of rusting

This lesson is taught in a series of lessons on different chemical reactions, following on from a lesson that went through why some metals corrode, what is needed for corrosion/rusting to occur and how to prevent corrosion. This was taught to a top set Yr 8 set who are set into two animal groups (squid = top, crab = bottom). Lesson is differentiated for the two groups to allow individual work for the top group and paired work for the bottom half - worksheet attached to enable bottom group to achieve LO. We spend one lesson planning this and then set up the expt during next lesson and leave it to run over half term to maximize time for rusting. In my school I use this lesson to assess one strand of scientific investigative skills that count towards our School's Baccalaureate.