Solubility Investigation in Science

Year 9 have been preparing for their internal KS3 summative science assessment (taking place in January) by carrying out a practical investigation on solubility.  The aim is to find out which solute is most soluble in water.  Students need to identify variables, plan the investigation and carry out the techniques carefully to get accurate results.  What better way to revise for the 'investigative skills' component of the exam?