What is the insulation method

1. pour 80cm3 of hot water from the kettle to a beaker 2. place cardboard lid with thermometer inside to beaker so it’s bulb is in the hot water 3. record temp of water and start the stopwatch 4. record temp of water every 3 mins for 15 mins 5. repeat steps using different materials/more layers of material on the beaker 6. plot a graph of temp in degrees celsius against time taken in mins