Knowing the cooling rate of an item is a useful tool in any science experiment. The process can be timeconsuming, but the more accurate data that is taken the more accurate your results will be. Graphing the cooling rate on graph paper also can help you visualize and explain the process.
Things You'll Need
 Thermometer
 Heat source
 Graph paper

Record the room temperature of the item for which you will be finding the cooling rate.

Heat the item significantly, about double the room temperature if possible.

Record the temperature immediately after removing the heat source.

Take the temperature of the item every minute and record the temperature each time. Continue to write down the temperatures until the item has cooled to the starting room temperature.

Construct a graph on the graph paper using the results. Plot temperature versus time on the X and Y axis.

Plot the results onto the graph and draw a cooling rate curve line by connecting your dots.

Calculate the cooling rate by dividing each temperature data point by its corresponding time data point then average all of your answers to achieve a cooling rate. In other words, the change in the temperature divided by the change in time will give you an average temperature rate change.
References
 Photo Credit thermometer image by Dusan Radivojevic from Fotolia.com