A student uses ice cubes to investigate the time taken for different masses of ice to melt when the ice cubes are placed in water. Plan an experiment using ice cubes to investigate how the mass of ice affects the time taken for the ice to melt. You are not required to do this experiment. The following apparatus is available: top pan balance supply of ice cubes 250 cm³ beaker supply of cold water stopwatch. You may also use other apparatus and materials that are usually available in a school laboratory. In your plan, you should: • explain briefly how to do the investigation • state the key variables to keep constant • draw a table, with column headings, to show how to display readings (you are not required to enter any readings in the table) • explain how to use these readings to reach a conclusion. You do not have to include a diagram of the apparatus you use but you may do so if it helps your plan.