This document discusses the scientific method as applied to forensics. It notes that forensics involves both crime scene investigators who collect evidence and laboratory technicians who analyze it. The scientific method involves making observations, forming a hypothesis, performing experiments, developing a theory or law, and presenting conclusions. In forensics, this process includes collecting evidence at a crime scene, forming a hypothesis about what occurred, conducting analyses in the lab, revising the hypothesis based on results, and presenting the case in court. Eyewitness accounts are often unreliable due to human perception and biases. Lab write-ups for this class should include title, background, purpose, hypothesis, procedure, data collection, data presentation, and conclusion.

1. Scientific Method
Application to Criminalistics and
Forensics

2. What is Forensics?
• Forensics is the application of science to the law
that is enforced by local law enforcement.
• There two critical pieces that make up forensics
(also known as criminalistics):
– Crime Scene investigator: The people who interpret
what is and is not evidence at a crime scene, as well
as putting together the puzzle of what happened.
– Laboratory technicians: The people who are the
experts at analyzing evidence (prints, DNA, etc.)

3. The most common subjects
• Chemistry
• Biology
• Firearms/ballistics
• Document
examination
• Toxicology/drug
analysis
• Fingerprints
• Odontology
• Engineering
• Geology
• Entomology
• Physics

4. Scientific method
• In science, as you all know, we use the
scientific method to answer questions.
• What are the parts of the scientific method?
• Make an observation
• Form a hypothesis
• Create/perform an experiment
• Scientific Theory
• Scientific Law

5. What does it look like in Forensics?
Observations ExperimentsTheory
Observations
Hypothesis
Experiments
Experiment
If hypothesis is false Make slight modifications
Collect evidence
Conclusion/final
hypothesis
Collect evidence
There is a constant evolution of the
original ideas based on the evidence found
and the conclusions made.
Turn the case over to
the judicial system
Wait for more
evidence to appear

6. Making Observations:
Facts vs. Perception

7. Perception is faulty!
Brain Games

8. Eyewitness accounts
• Vary considerably from person to person
– Prejudices, personal beliefs, motives
• Your brain fills in the details over time

9. • Our ability to observe is largely affected by
our environment:
– Weather, level of chaos, personal focus, etc.
• The innocence project found that 87% of
wrongful convictions are due to incorrect
eye witness accounts

10. In this class…
• Observations are CRITICAL!!
• The rest is important too
• Here is what to expect on labs

11. Lab write-ups
• Title
• Background information
– Done before the labs
• Purpose
• Hypothesis
• Diagram
– Pictures of apparatus used
with labels
• Procedure
– Details, details, details.
• Data collection
– Observations, data tables,
Calculations
• Presenting data and
Graphs
– Pictures of scene
• Conclusion
– Analyze the data

12. Expectations on labs
• Do your own work!
• Organization and neatness counts
– If I can’t read it or find it then its worthless
• Complete analysis of evidence
– Analyzing evidence is the point of this class
• Thorough conclusions in complete
sentences
– Prove to me you know what you are talking
about