I came across a version of this activity at STANYS conference last fall. I have adjusted it a bit to meet my classroom needs. The students design a procedure to test the affect of reactant concentration on reaction rate. I opened up the activity with a demonstration of the Iodine clock reaction and had students run through a QFT. Magically the question generated by the students just happens to be the lab I have set up!! I have attached my version of the lab as well as some additional handouts I use for CER. Enjoy. Please let me know how it goes.