Education Technology

Forensics with TI-Nspire™ - Case File: A Killer Cup of Coffee

Published on 05/08/2013

Activity Overview

In this activity, students will use colorimetry to calculate the concentration of an unknown solution by measuring how it absorbs a specific wavelength of light.


  • Use Beer’s law to determine the concentration of simulated iron(III) thiocyanate (FeSCN2+) in an unknown solution.
  • Use colorimetry to determine the concentration of a colored species in a solution.
  • Use a linear relationship to model the data (Beer’s law).
  • Learn the importance of carefully prepared standards.

About the Lesson

  • In this data-gathering activity, students will use Beer’s law to determine the concentration of iron(III)thiocyanate (FeSCN2+) in an unknown solution.
  • Solutions used during this lab require teacher preparation prior to class.
  • Students will collect data using the Vernier EasyLink™ or TI-Nspire Lab Cradle with the Vernier Colorimeter.
  • The student activity sheet and .tns file contain the complete instructions for data collection. All assessment questions are also included in both places giving you the flexibility to either collect the .tns files with student data/answers (using TI-Nspire Navigator) or the student activity sheet.