Chromatography
What is chromatography used for?
Separating and analyzing the different substances or components in a mixture.
What is arson?
The intentional and illegal setting of a fire.
What is an eyewitness?
A person who saw an event happen.
What are the three basic fingerprint pattern types?
Loops, whorls, and arches.
What is an alibi?
Evidence or a claim that a person was somewhere else when a crime occurred.
If two ink samples produce the same pattern of colours on a chromatography strip, what might this suggest?
The inks may contain the same or similar dyes.
What three things make up the fire triangle?
Heat, fuel, and oxygen.
Name one factor that can affect the accuracy of an eyewitness's memory.
Stress, poor lighting, distance, time, distractions, or the presence of a weapon.
Which fingerprint pattern is the most common?
Loop
What does a forensic scientist study?
Evidence from a crime or investigation using scientific methods.
Why is chromatography useful in forensic science?
It can help investigators compare substances such as inks, dyes, or other mixtures found at a crime scene.
What is an accelerant?
A substance that can help a fire start or spread more quickly.
Why might two eyewitnesses give different descriptions of the same event?
Memory can be affected by stress, attention, expectations, lighting, questioning, and the passage of time.
What is trace evidence?
Small pieces of physical evidence that can be transferred between people, objects, and places.
What is an accomplice?
Someone who helps with the crime but does not commit it.
What are all the materials you need to complete a simple paper chromatography experiment
Ink, Filter paper, Icy pole stick, beaker, methylated spirits
Why can determining the cause of a fire be difficult?
Fire can destroy or alter evidence and change the appearance of the scene.
Why can torture be unreliable as a method of interrogation?
A person may give false information or falsely confess simply to make the pain or pressure stop.
A suspect's clothing contains fibres that are similar to fibres found at a crime scene. What might this evidence suggest?
The fibres could indicate contact or a connection between the suspect and the crime scene, but the evidence alone may not prove that the suspect committed the crime.
Why is preserving a crime scene one of the most important first steps in a forensic investigation?
Once evidence is moved, damaged or contaminated, its original condition may be impossible to reconstruct accurately.
How do you calculate the Rf value in chromatography?
Formula:
Rf = distance travelled by substance ÷ distance travelled by solvent
Investigators find multiple sources of origin for a particular fire, What could this indicate?
It could indicate that the fire may have been intentionally set in multiple locations, suggesting possible arson.
What does PEACE stand for?
P — Planning and Preparation
E — Engage and Explain
A — Account, Clarification and Challenge
C — Closure
E — Evaluation
What is the difference between human hair and a fibre as forensic evidence?
Hair is biological material produced by a person or animal, while a fibre is a material such as cotton, wool or synthetic material.
The “Independent Variable” in an experiment is…
The variable that the scientist changes or controls.