Set up the apparatus by placing a small beaker inside the larger beaker
Fill the small beaker with boiling water from a kettle
Place a piece of cardboard over the beakers as a lid. It should have a hole suitable for a thermometer and place it through this hole and into the water
Record the temperature of the water and start the stopwatch
Record the temperature of the water every 2 minutes for 20 minutes, or until the water reaches room temperature