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Mr. Williams' Forensic Science Final Exam Review Part 1

Final Exam Review Questions
STUDY
PLAY
What are the 5 steps in crime scene investigation?
Secure crime scene
Observe crime scene
Document crime scene
Search crime scene
Collection & preservation of evidence
Who should certify that the body is "dead"?
Medical examiner
What does observing a crime scene involve?
Initial walk through
Plan of action
What are the 4 search patterns for crime scenes?
Grid, quadrant or zone, spiral, line or strip
How do you decide what pattern to use?
Based on size/location of crime scene and number of investigators.
How do you package evidence at a crime scene?
Individually, allow wet objects to dry
What evidence cannot be packaged immediately? Why?
Wet evidence because it could be destroyed by mold or mildew
Describe anthropometry.
Taking body measurements as a way to distinguish one individual from another
What two scientists were known for devising experimentation for blood types?
Karl Landsteiner and Leon Lattes
Who was responsible for courts acceptance of documents as scientific evidence?
Albert Osborn
Odontology
Determine skeletal remains through dental records
Toxicology
Determine whether drugs are in a human body
Anthropology
Determine if bones are human or animal
Psychology/Psychiatry
Determine competency of a suspect to stand trial
Entomology
Determine time of death using insects
Engineering
Investigate structural failure and investigate accidents
Pathology
Perform autopsies to determine death
Computer Forensics
Recover data from digital media
Criminalistics
Analyze and interpret physical evidence
Document Examiners
Analyze ink, paper, toner in questioned documents
What is a misdemeanor?
Minor Crime
What is a felony?
Major Crime
What court case in 1923 set the "general acceptance" of scientific evidence?
Frye vs. United States
What are the roles of an expert witness?
Establish credibility through credentials, background experience.
Evaluate evidence.
Render an opinion about the evidence.
What do forensic scientists use physical evidence for?
Identification and comparison.
What is identification used for?
To determine physical or chemical identity
What is comparison analysis used for?
To determine whether a common origin exists
What is the difference between individual characteristics and class characteristics?
Exact identity compared to a common origin
What are 2 examples of physical properties?
Density, color, texture, odor
What are 2 examples of chemical properties?
Flammability, reactivity
What is the SI unit for length?
Meter
What is the SI unit for volume?
Liter
What is the SI unit for mass?
Grams
What does kilo mean?
1000
What does deci mean?
1/10
What does hecta mean?
100
What does milli mean?
1/1000
What does centi mean?
1/100
What does deca mean?
10
What is the formula to calculate density?
Mass/Volume
What is refraction?
Bending of light as it moves from one medium to another
Example- air to water
What is the range for pH?
0-14
What can fracture patterns tell an investigator?
Sequence of events
Direction of impact
High or low velocity impact
What are the types of fracture patterns of glass?
Radial and concentric
If the refractive index of glass matches that of a liquid, what will you see when ou put the glass sample inside the liquid?
The glass will disappear
What are natural fibers?
Fibers made from animals or plants
What are some examples of natural fibers?
Cotton, wool, silk, hemp
What are synthetic fibers and what would be an example?
Manmade or altered fibers
Acetate, rayon, polyester
What type of fibers contain proteins?
Animal fibers
What three fibers dissolve in formic acid?
Nylon, silk, acetate
When performing the sulfur test, what color precipitate should show a positive outcome?
Black or dark grey
What is the only fabric to dissolve in acetone?
Acetate
What are examples of mineral fibers?
Asbestos, rock wool, fiberglass
What are examples of cellulose fibers?
Cotton, rayon, cullulose acetate
What is the difference between hydrophilic and hydrophobic?
Hydrophilic-water absorbing
Hydrophobic-water repelling
How should you collect fiber evidence?
Make tape lifts, bag evidence individually, removed fibers should be folded into a sheet of paper and stored in a paper bag
How often does hair grow?
1 cm/month
What are the 3 layers of hair?
Cuticle, cortex, medulla
Which layer has pigment granules?
Cortex
Which layer is resistant to chemical decomposition?
Cuticle
How can the medulla be classified?
Interrupted, fragmented, continous, stacked, absent
What type of medullas do animals usually have?
Stacked, continuous or interrupted
What type of medullas do humans usually have?
Continuous, fragmented or absent
What are th 3 stages of growth?
Anagen, catagen, telogen
How long does each stage of growth last?
Anagen- up to 5 years
Catagen- 2-3 weeks
Telogen- 2-6 months
Can scientists determine body area that hair came from comparison?
Yes
What is the best stage for DNA comparison of hair?
Anagen stage
If there is no nuclear DNA present, what type do scientists use?
Mitochondrial DNA
When taking reference samples from the head, how many hairs do you need?
50 full length hairs