A student investigates how the thickness of insulation wrapped around a metal container affects the rate at which it loses heat.

The following apparatus is available:

• a metal container
• a roll of felt (insulating material) of uniform thickness
• scissors and rubber bands
• a thermometer
• a stop-watch
• a supply of hot water

She can also use other apparatus and materials that are usually available in a school laboratory.

Plan an experiment to investigate the effect of the thickness of the insulating material (measured by the number of layers wrapped around the container) on the rate of heat loss from the container.

You should:

• draw a diagram of the apparatus used
• explain briefly how you would carry out the investigation
• state the key variables to be kept constant
• draw a table, or tables, with column headings, to show how you would display your readings (you are not required to enter any readings in the table)
• explain how you would use your readings to reach a conclusion.