A student investigates how the concentration of salt dissolved in water affects the time taken for an ice cube to melt completely.

Plan an experiment to investigate how the mass of salt dissolved in a fixed volume of water affects the time taken for a standard-sized ice cube to melt.

The following apparatus is available:

• Beaker ($250{cm}^3$)
• Supply of identical ice cubes
• Supply of distilled water at room temperature
• Supply of table salt
• Spatula

In your plan, you should:

• write a list of additional apparatus to use
• explain how to carry out the investigation
• state the key variables to keep constant
• draw a table, or tables, with column headings, to show how to display the readings (you are not required to enter any readings in the table)
• explain how to use the readings to reach a conclusion.