Introduction

Could the dirt on a car be used to connect a suspect to a crime scene?

  1. Yes, dirt has unique properties that can act as location markers.
  2. No, the dirt could have come from anywhere that the suspect has been.
A car with dirt on the tires.

In this lesson, you will learn how to collect and analyze soil samples and use this knowledge to determine if any of the collected samples match an unknown sample taken from a suspect's car.

Lesson Objectives

Following successful completion of this lesson, students will be able to...

  • Use chemical and physical analysis to differentiate between soil samples.

Essential Questions

  • What is the difference between individual and class characteristics?
  • How do you determine what evidence at a crime scene is valuable?
  • What is the proper way to document information from a laboratory analysis? What should be included on this report?
  • How is the scientific method used by forensic scientists and crime scene invesdtigators?

Enduring Understandings

  • Forensic results are open to the interpretation and subject to the limitation of the pathologist's knowledge and methods.
  • An exchange of material will occur whenever someone is at a crime scene (Locard's Exchange Principle). Materials left behind (or carried away) from the crime scene as well as markings and impressions from those items can be linked to an individual or item.
  • The principles of scientific inquiry are required in all crime scene and forensic science analysis.

The above objectives correspond with the Alabama Course of Study: Forensic Science and Crime Scene Investigation standards: 5, 14, 25, 43.