What Time Did The Potato Die?

Rebecca Sunderman
The Evergreen State College, Olympia WA 98505
Created: 2007-04-16 06:11:10 Last Modified: October 30, 2007 13:28
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This material is replicated on a number of sites as part of the SERC Pedagogic Service Project


In this Spreadsheets Across the Curriculum activity, students use "crime scene" data of body temperature vs. time to determine the time of death of a potato crime victim. Students will learn to create a spreadsheet, make graphs, add trend lines, and work with linear and exponential curves in an effort to graphically estimate and algebraically calculate the potato's time of death. The module introduces the mathematical concepts of linear and exponential graphing, unit conversions, and trend lines.

Learning Goals

Students will:
  • Learn how to create and work with a spreadsheet in Excel.
  • Learn how to create a graph within Excel.
  • Gain experience with adding and working with trend lines.
  • Gain experience with converting units while solving a problem.
  • Gain experience with interpreting graphs and choosing the best graph to represent a given set of data.
In the process, the students will:
  • Model an exponential-decay phenomenon to solve a problem.
  • Learn more about the complexities of interpreting time of death in a forensic setting.

Context for Use

This activity was designed for lower-division college students taking forensic science. Student math levels were expected to be diverse with some students not having math beyond high school precalculus. The module could be used in an advanced high school class.

Description and Teaching Materials

PowerPoint SSAC2005:HV8079.RS1.1_student (PowerPoint 403kB May27 10)

The module is a PowerPoint presentation with embedded spreadsheets.

If the embedded spreadsheets are not visible, save the PowerPoint file to disk and open it from there.

This PowerPoint file is the student version of the module. An instructor version is available by request. The instructor version includes the completed spreadsheet. Send your request to Len Vacher (vacher@usf.edu) by filling out and submitting the Instructor Module Request Form.

Teaching Notes and Tips

This module best works as an in-class assignment in a computer lab where students each have access to a computer. I schedule a two-hour time block for this module. If you have a lot of students to assist, it is quite effective to have those students very familiar with Excel help others.


The last page of the module has a homework assignment asking students to determine the time of death of a zucchini crime victim.

References and Resources