Newton’s Law of Cooling Exploration

Excel

Model Development

Each group will develop a model of Newton’s Law of Cooling in Excel and create an Excel spreadsheet with the following headings:

The differential equation form of Newton’s Law of Cooling is

                    (1)

This equation can be modeled as follows:

Note:This is a good time to discuss computational modeling and why there is a need to model systems.

To model this equation in Excel, the following names (or similar) will be defined: water temp, ambient temp, k, and delta t.  The names are assigned by highlighting the variable name and then selecting “Insert”, “Name”, and “Define.”  In the “Refers to:” box type in the cell where the value of the variable is stored.   ontinue this procedure for all variables.

The model is now entered into the spreadsheet as follows: to find the new temperature, take the previous temperature and subtract the product of the cooling constant (k) and the difference between the previous temperature and room temperature (ambient temperature).

Enter the formula and then fill down.  The model can now be graphed by highlighting the model column and following the steps in the Excel Chart Wizard for XY (Scatter).

The students can now change the values for each of the four variables listed in the spreadsheet and observe the results on the graph.

Back