Lesson 2
Is it possible for forensic scientists to collect every object from a crime scene?
No
What are individual characteristics of a substance
Soil at a crime scene includes...
Dirt, and any other substances that may be mixed with the dirt such as animal matters, leaves, asphalt etc
What is an example of a physical property of the desks
Made of wood. Brown Color. Solid. Etc...
Why are witnesses not always reliable?
They can be difficult to work with
They can be biased
Memories are not always reliable
Why might 2 soil samples collected from different areas of a crime scene have different colors
One sample is wet, one sample is dry.
One sample has a different composition than the other
What are ridge characteristics
The lines on your fingers that create a unique fingerprints
What are some examples of impressions evidence
footprints, fingerprints, tool marks
What types of objects can make a hole in glass similar to a bullet hole
Rocks or stones
What is a photo array
A group of photos that a witness uses to identify a potential suspect
What is a physical property of a substance
The properties that we can observe: Density, weight, color
How can class characteristics be useful as evidence in a criminal trial
Help support other evidence and corroborate what happened
Why might 2 different soil samples collected from different areas of a crime scene have different colors?
They may have different compositions
One sample may be wet while the other may be dry
How do you know if a test is reliable
You conduct a test multiple times on the same substance and get the same results.
Is a subpoena necessary for a witness to testify in a criminal trial?
No
How are you able to determine if an unknown substance is a match to a known substance
You compare them
How is law enforcement able to use a bullet hole to determine what direction a bullet cam e from
The bullet home is wider on the side the bullet exited from
How do you collect evidence that may have soil on it
You want to collect the whole piece of evidence and place it in a plastic bag
What is the difference between radial and concentric fractures in glass
Radial fractures extend away from the point of impact. Concentric fractures circle the point of impact
when should the Miranda Rights be read
When a suspect is being held in police custody
Describe the difference between documentary evidence and demonstrative evidence
Documentary Evidence: Evidence that documents what happened at a crime scene- Video recordings, pictures, voice recordings
Demonstrative- Evidence that demonstrates what may have happened at a crime scene- Models
Describe the difference between chemical properties and physical properties
Chemical properties described the chemical makeup of a substance and how it will react when put in contact with another substance
Physical properties describe the physical makeup of the substance without describing how it will interact with anything else
What is the best way to preserve an impression of a shoe print?
Make a silicone rubber mold of it
Why would you need to use an electrostatic dust print lifter
If the impression is not very deep, you can still obtain an image of the print
What is the purpose of the Miranda rights
So that suspects understand their right to an attorney