Education Technology

Forensics Case 11 - Ashes to Ashes: Using evaporation rate to identify an unknown liquid

Activity Overview

In this activity, students understand that evaporation rate is a characteristic property of a liquid. Based on this fact, they identify the solution and the likely accelerant in a case of arson. They compare the evaporation rates of the accelerants found with the suspects with those near the crime site.

Key Steps

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    Each graph that students make will show a decrease of temperature as each liquid evaporates. Then they will compare the temperature differences to identify the suspect who had traces of the matching accelerant.

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    The graphs of each unknown is compared to the known sample found at the crime scene. Which substance belonging to which suspect came closest?