Name:_____________________________________________________ Period: ___________

2014 Fall Exam Review - Forensic Science

• 5 Bonus Points on Final Exam = Completed Review (all blanks filled in) and handed in at beginning of

class on Tuesday, Dec. 16th • If you are exempting, you do not need to complete the Review. • Covers Units 1-8; 100 questions; Approx. 12 questions per unit; No Bonus other than completion of this

Review • Resources required for Review: Unit PPTs, Quizzes, and Chapter Review Questions/Test Reviews

Unit 1: Applied Crime Scene Analysis 1. What is the rule when combining water and acid in the lab? Always add acid to water to prevent

acid from splashing up into your face… remember alphabetical A W

2. What does PPE stand for? Personal Protective Equipment 3. Microscope Parts and Functions:

a. Diaphragm – Controls the amount of light passing through the stage b. Stage – Supports the slide c. Stage clips – Holds the slide in place on the stage d. Fine Adjustment Knob – Sharpens focus e. Course Adjustment Knob – Brings image into initial focus

4. Define the following terms: a. Tainted evidence- evidence that is inadmissible because it was obtained by illegal means. b. Hearsay evidence– evidence that a witness has no direct knowledge of and must be proven by another source (i.e. witness did not see the crime occur but heard from a friend what happened; that friend would be called to testify in court). c. Corroborating evidence– evidence that strengthens other evidence in the case. d. Incriminating evidence– evidence that establishes guilt of a party (opposite of exculpatory). e. Real/Physical evidene– evidence that is relevant and material to the crime; it usually can be produced in court (i.e. a knife can be submitted into evidence). f. Demonstrative evidence– evidence that demonstrates or illustrates the testimony of a witness (i.e maps, crime scene diagrams, animations). g. Exculpatory evidence – can establish the innocence of a defendant. h. Forensic Science – the application of science to criminal and civil laws. i. Known/Reference Standard – evidence sample that we KNOW where it came from: i.e. blood sample drawn from the suspect or hair sample from the victim’s head. It is used to compare to evidence at the crime scene. j. Locard’s Exchange Principle – when 2 or more objects come in contact with one another, they exchange materials between them k. Corpus Delecti – forensics is needed to prove a crime has actually been committed; this is known as the “body of the crime”. l. Modus Operandi – the manner or way in which someone commits a crime; the person’s “M.O.”

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5. List 3 main functions of a forensic scientist – a. Skilled in applying the principles and techniques of the physical and natural sciences to

the analysis of various types of evidence. b. Train law enforcement personnel in the proper recognition, collection, and preservation of evidence. c. Provide expert court testimony

Unit 2: History and Careers

6. What is the “CSI Effect? Many non-law enforcement people (ie. Jurors) think real crimes are solved just like it is portrayed on the TV show “CSI”…. Fast, large amounts of incriminating evidence, driving in Hummers, and high profile.

7. Name the scientist responsible for the following:

a. He had the first criminal laboratory - Edward Locard b. He is credited with the first recorded notes about characteristics of fingerprints – Marcello

Malpighi c. Wrote the first treatise describing the application of science to criminal investigation – Hans

Gross d. Discovered blood could be grouped into 4 types – Karl Landsteiner e. Made significant contributions using the microscope – Walter McCrone f. Developed the first blood typing test for dried blood stains – Louis Lattes g. Father of Toxicology – Mathieu Orfila h. Published the first definitive study of fingerprints and developed the classification system for

filing them – Francis Henry Galton i. Developed the first DNA Profiling test – Sir Alec Jeffries j. Developed a system of body measurements for individual identification of a person –

Alphonse Bertillon 8. Name the type of forensic scientist that performs the following duties:

a. Works primarily with the physical evidence to analyze, identify, and interpret items that may help solve a crime - Criminalist

b. Studies the human skeleton system mainly to help identify deceased remains that are skeletonized – Forensic Anthropologist

c. Assists when structural failures occur or maintenance and manufacturing procedures are in question, reconstructs accidents, explores causes of fires & explosions – Forensic Engineer

d. Applies the principles of dental science to the law – Forensic Odontologist e. Studies the effects of drugs and chemicals on the human body - Toxicologist f. The study of insects and their relationship to criminal investigation – Forensic Entomologist g. Perform autopsies and determine the cause and time of death – Medical Examiner h. Analyzes materials such as ink, paper, and toners to determine the legitimacy of the material

– Document Examiner i. Studies DNA, blood types, and heredity and applies them to evidence – Forensic Serologist Unit 3: Legal Systems and Ethics 2

9. Give the ethical term for each of the following:

a. Proof a crime lab is competent and credible in evidence examination – Accreditation b. Says what we should do; study of ideal behavior and principles which guide that behavior - Ethics c. Practical applications of ethical principles; modes of conduct - Morals d. Says what we must do - Law e. Person or organization with a legitimate interest in a given situation - Stake Maker f. Standards or ideals which serve as guides by which we live and make decisions - Values

g. An effect where a renowned scientist gets more credit for current work than is actually deserved due to past accomplishments – Mathew Effect

10. Give the Amendment number for the following: a. Protection against illegal search and seizure – 4th b. Protection against being tried twice for the same crime – 5th (Double Jeopardy) c. Right to an attorney, speedy trial, informed of charges within 72 hours, subpoena witnesses – 6th d. Right to an impartial trial by jury – 7th e. Protection against excessive bail, fines, & cruel and unusual punishment – 8th

11. List three situations when an officer does NOT need a search warrant: a. In an emergency = no warrant needed b. Suspect gives consent = no warrant needed c. Illegal drugs or guns in plain view = no warrant needed

12. The burden of proving the defendant’s guilt in a criminal case is always the responsibility of whom? The Defense Attorney

13. What is the Latin term for “let the decision stand” and is the principle behind the precedents set by upper courts? Stare Decisis

14. Legal or Illegal? a. The police see “Poppy” standing on a corner on a downtown street reading the paper. It is rumored that he is a marijuana dealer. They stop and search him and find drugs in his pocket – Illegal; no probable cause or reasonable suspicion because drugs not in “plain view”

b. Enticing Esmerelda is arrested for reckless driving. Then the police search her purse and find a pistol for which she has no permit – Legal; once you are arrested, you can be searched for the officer’s safety

c. The police are chasing “Whitey” who is carrying a small baggie of suspected cocaine down an alley. When Whitey darts into his own house, the police continue their chase and seize the baggie just before the man could flush it down the drain – Legal; this is an emergency situation to catch him before he flushed the drugs; no warrant needed to enter the suspect’s house

d. Gorgeous George is pulled over for speeding and receives a ticket. Then, the officer asks George to get out of the car and begins a search of his vehicle, finding a large rifle on the floor in the back seat and confiscates it - Illegal; George was not arrested and there was not reasonable suspicion for searching the vehicle. If George gave consent, then it would be legal. 3

15. Who is the final evaluator of the forensic evidence during the trial? The Jury 16. Who is responsible for determining the admissibility and reliability of scientific evidence during the

trial and is known as the “gatekeeper”? The Judge

17. The standard of evidence in a criminal trial is known as proof _beyond_ a _reasonable_ doubt. In order for a jury to convict, they must believe that the evidence presented against the defendant was far greater than the evidence presented for his innocence.

18. Define the following and give an example: a. Individual characteristics/evidence – Evidence that can be linked to a unique, specific source with a very high degree of probability (i.e. ridge characteristics on a fingerprint, striations of a bullet, irregular edges of paper torn in half and puzzle-fitted, Nuclear DNA typing, wear pattern on shoe tread, paint chip fits in damaged part of suspect’s vehicle) b. Class characteristics/evidence – Evidence that can only be associated with a group and never a single source (i.e. ABO blood typing, type of glass compared to broken crime scene window, fibers, hairs without DNA analysis, soil, standard automotive paint layers)

19.. __Frye_ v. _United States_ set out the requirements for the admissibility of expert testimony.

20. _Chain__ of _Custody__ – the witnessed, written record of all individuals who had the evidence in their possession from the crime scene to the courtroom; and when, where, and for what purpose this transfer of evidence occurred. 21. To be considered a reliable _Expert__ witness, a person must be able to demonstrate significant experience in a particular field. A college degree is NOT necessarily required. However, forensic scientists will need a college degree and experience to be qualified as an expert witness in a particular forensic field. Unit 4: The Crime Scene 22. First responding officer at the crime scene is responsible for securing the scene by doing what three things – a. obtain medical assistance b. arrest suspect c. seal off crime scence 23. List the 3 methods for recording the crime-scene – a. narrated videotape b. photography c. crime scene sketching & notes 24. List the 4 types of search patterns - a. strip or line b. spiral c. zone or quadrant d. grid

25. List a minimum of 8 things that must be included in the crime scene sketch – a. compass b. all measurements with a scale c.date, time, address d. Victim’s name e. walls, windows, doors f. type of crime g. location of all evidence including bodies w/legend h. Investigator’s name

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26. How should the following materials be collected for submission to the crime lab? a. blood-stained items – always in paper to prevent mold b. charred debris from a fire – in a new, unused paint can or glass jar c. fingernail scrapings/clippings - paper bindle d. what is a substrate control ? – a swabbing or cutting of an unstained area near the evidence used to ensure that the surface on which a sample has been deposited does not interfere with analysis results. 27. Who establishes the cause of death? The Medical Examiner or Coroner of Forensic Pathologist 28. List the 5 categories in which manner of death can be classified – a. Homicide b. Suicide c. Accidental d. Natural (cancer, heart attack) e. Undetermined

29. List the 8 items to be collected from the body – a. Victim’s clothing b. Fingernail scrapings/clipping c. Head & Pubic Hair d. Blood (for DNA typing) e. Vaginal, anal, and oral swabs (in sexual assaults) f. Recovered bullets from the body g. Hand swabs from shooting victims for gunshot residue h. Ocular Fluid for potassium levels in the vitreous humor

30. Define rigor mortis – shortening of the muscles causing stiffening of the joints and the time period in which it occurs – appears in first 24 hrs and disappears within 36 hrs 31. Define livor mortis – settling of blood in areas of the body closest to the ground and its time period – immediately and lasts up to 12 hrs 32. Algor mortis – loss of heat by a body and its time period – begins w/i 1 hr and # of degrees F lost per hour – 1-1.5 deg F 33. Which two of the mortis above could be used to tell if the body had been moved after death – rigor mortis and livor mortis 34. Where is a buccal swab taken and for what purpose – taken from the inside lining of mouth/cheek as a known DNA standard of the person 35. Upon death, what happens to the levels of vitreous humor in the eye – the level of potassium increases the longer the person is deceased. Unit 5: Physical Evidence 36. Evidence having class characteristics can __exonerate__ or __exclude___a suspect by decreasing the probability that the evidence found at a crime scene is random. 37. If the laboratory can piece broken glass from a window or headlight together, then the evidence has ___individual___ characteristics. 38. Determining that an explosive mixture contains dynamite is an example of the process of _____ identification 39. A single-layer paint chip normally can be expected to have ___class__ characteristics 40. The “jigsaw fit” of known and questioned fragments is important for court presentation primarily because - demonstrates common origin when a match is made

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41. The computerized database used to store DNA information is called __CODIS_ 42. Name the three types of Physical evidence that can be found at a crime scene and give at least two examples of each a. Biological – blood, semen, hair, natural fiber etc. b. Impression- fingerprints, footprints, tire tracks etc. c. Manufactured – bullet, synthetic fibers, drugs, trace chemicals 43. The computerized database used to store shoeprint information is called __SICAR__ 44. Evidence with individual characteristics can lead to a determination of common origin (single source). Tell weather each type of evidence is class ( C ) or individual (I)? __I__Matching two fingerprints ___I_Striations marks on a bullet __C___Finding the make and model of a tire __C__single-layer paints

__I__DNA __I__wear patterns on tires __I__random striations on tools __I_ Fitting together the irregular edges of broken glass

45. The likelihood of finding class evidence is ( greater than / less than) the likelihood of finding physical evidence with individual characteristics.

46. Physical evidence is considered to have (greater / less ) value than that of eyewitness

(testimonial) evidence. 47. The corroborative use of physical evidence means that it can be used to - Support other

investigative findings 48. Physical evidence can be used to exonerate or exclude a person from suspicion if the

___Reference/ known__ sample does not match with the evidence at the crime scene 49. Forensic databases are maintained for all of the following: A) DNA B) fingerprints C) Tire/Shoe D) Paint E) Bullets 50. In what year did the Combined DNA Index System (CODIS) become fully operational? 1998 51. The examination of a paint chip found on a hit-and-run victim’s garment side-by-side with paint

removed from a vehicle suspected of being involved in the incident is an example of: comparison 52. To calculate the overall frequency of occurrence of a blood type in a population, the Product Rule

__ can be applied by using a series of blood factors that occur independently of each other. 54. ___IAFIS____ is a national fingerprint and criminal history system maintained by the FBI and

launched in 1999. 53. Which of the following is NOT a type of physical evidence Drugs Document Impressions Eye witness statement

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54. PDQ is the national databases that are currently available to the forensic community

for_Paint____ 55. Which of the following is NOT a role of physical evidence at crime scene reconstruction.

A. Demonstrate sequence of events B. Give motive C. Contradict suspects D. Support witness statements

56. How do you calculate magnification eyepiece x objective = total magnification 57. List the crime scene unit that would examine each piece of evidence a. blood -serology b. tookmarks –trace c. fibers trace d. bones- anthropology e. bullets - ballistics 58. Explain the difference between the identification and comparison of physical evidence. Cite one example of each .

Identification – is figuring out the chemical components of an unknown Ex. Figuring out the chemical make-up of a bomb Comparison- is matching a known to an unknown Ex. Matching the DNA found on the victim to a suspect

Unit 6: Analysis of Glass

1. Know all vocabulary definitions. (you were given the Chap 4 terms & defined them) 2. Name 4 chemical properties & 4 physical properties of matter.

Chemical: burning, rusting, decomposing, and color change Physical: weight, volume, color, boiling & melting point

3. Name 4 types of chemical reactions and give “ABCD diagram” for each.

Synthesis : A + B AB Single Replacement: AB + C CB + A Decomposition: AB A + B Double Replacenent: AB + CD AD + BC

4. Name the 3 basic units of measurement for length, mass, and volume in the metric system. Length = meter Mass = gram Volume = liter

5. What is the relationship between cm3, cc, and mL for liquids in the metric system? 1cm3 = 1cc = 1 mL

6. Be able to perform metric conversions using King Henry and the Ladder Method (or method of your choice). a. 657. km = 657,000,000 mm or 6.75 x 106 mm b. 53.44 dg (decigrams) = 0.5344 Dg (dekagrams)

7. Be able to perform conversions using the Factor Label Method (Dimensional Analysis).

a. Know how many centimeters are in 1 inch: 2.54 cm = 1 inch

b. How many days are in 555,555 seconds?

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555,555 s 1 min 1 hr 1 day = 6.43003 days 60 s 60 min 24 hr

c. How many centimeters are in 3545 feet? 3545 ft 12 in 2.54 cm = 108,051.6 ~ 108,100 cm 1 ft 1 in

8. Compare attractive forces and density in the three state of matter. a. Which state has the strongest attractive forces between molecules? solid b. Which state has the weakest attractive forces between molecules? gas c. Which state is generally considered the most dense (higher density)? solid d. Which state is generally considered the least dense (lower density)? gas e. Which state has no specific shape and no specific volume? gas f. Which state has a specific shape and a specific volume? solid g. Which state takes the shape of its container and has a specific volume? liquid

9. Describe the two models of the behavior of light.

Light behaves as a continuous wave and as a stream of discrete energy particles known as photons.

10. As electromagnetic radiation moves through space, its behavior can be described as that of

a continuous wave.

11. Once radiation is absorbed by a substance, it is best described as discrete particles of

light known as photons.

12. Understand how the frequency, wavelength, and energy of light are related. a. High frequency means that the wavelength is always (shorter or longer) than low

frequency waves.

b. The higher the frequency, the (higher or lower) the energy of the wave.

13. What is the difference between the electromagnetic spectrum and the visible spectrum? The electromagnetic spectrum is the entire range of radiation in the universe; whereas, the visible spectrum is only a small part of radiation within the larger electromagnetic spectrum. In addition, the visible spectrum is the only part of the larger spectrum that we can actually see.

14. List the radiation types in order from the most dangerous (highest energy/highest frequency/shortest wavelength) to least dangerous (lowest energy/lowest frequency/longest wavelength).

Gamma rays, X-rays, Ultraviolet, Visible Light, Infrared, Microwaves, Radiowaves

15. List the colors of the visible spectrum in order from highest energy/highest frequency/shortest wavelength to the lowest energy/lowest frequency/longest wavelength.

Violet, Indigo, Blue, Green, Yellow, Orange, Red

16. The most commonly used temperature scale in science is the Celsius scale.

a. Celsius scale freezing point of water = 0 C ; boiling point = 100 C.

b. Fahrenheit scale freezing point of water = 32 F ; boiling point = 212 F.

17. What is the difference between mass and weight?

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Mass is the amount of matter an object contains and does not take gravity into consideration. Weight is the force with which gravity attracts a body.

a. What is the mass of a 7000 kg elephant on the Jupiter?

The elephant’s mass on Jupiter is still 7000 kg because mass is independent of gravity anywhere in the universe.

18. A 0.39 g glass fragment is placed in a test tube containing 5.0 mL of water. Once in the test

tube, the water level rises to a volume of 7.0 mL. What is the density of the glass fragment? D = m 0.39 g = 0.39 g = 0.195 g ~ 0.20 g V (7 mL – 5 mL) 2 mL mL mL

19. Generally speaking, how does temperature affect the density of a substance?

As temperature increases of the substance, the density decreases. a. Which is more dense, a substance at 100F or at 40F? 40 F

20. Why do light waves bend when traveling from one medium such as air into another medium

such as water? Light waves travel in air at a constant velocity until they penetrate another medium at which point the waves are suddenly slowed, causing the rays to bend.

21. What is the difference between refraction and refractive index?

Refraction is the bending of light waves because of a change in velocity as it penetrates another medium. Refractive index (RI) is the ratio of the velocity of light in a vacuum (air) to the velocity of light in the medium.

22. What two factors can cause refractive index to vary?

Both temperature changes and wavelength changes can cause refractive index to vary.

23. How does a crystalline solid like calcite refract a beam of light?

Crystalline solids refract a beam of light in two different light-ray components. a. What does this refraction result in?

It results in a double refraction and a dual image. b. What does birefringence have to do with your answer in “a.”

Birefringence is the numerical difference between the two refractive indices of the double refraction that occurs.

c. What kind of a solid is glass considered? Glass is a noncrystalline solid called an amorphous solid.

d. Does glass exhibit birefringence? No. Only crystalline solids exhibit double refraction and have birefringence.

24. Describe 5 characteristics of glass in general: Hard, brittle, amorphous substance, mostly sand, and mixed with various metal oxides.

25. What is in soda-lime glass? Soda is added to make it more workable and lime added to make it less dissolvable in water.

a. Give 2 examples of this glass: windows and bottles

26. What is in borosilicate glass? Boron oxide added to withstand high heat. a. Give 2 examples of this glass: test tubes and headlights

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27. How is tempered glass made?

It is made by rapid heating and cooling, repeatedly. a. How does tempered glass break?

Tempered auto windows break into small square-like pieces without sharp edges. Pyrex tempered cookware breaks into 1-2 large pieces instead of numerous very sharp pieces.

b. Give 3 example of this glass: shower doors, side & rear auto windows, pyrex cookware

28. How is laminated glass made?

It is made by placing a plastic film between two pieces of glass. a. Give an example: windshields

29. What are the two most important physical properties used to identify and compare glass

fragments? Refractive index and density a. These two physical properties ( ARE or ARE NOT ) considered intensive physical

properties.

30. What is the Flotation Method used for? It is used to determine and compare the densities of glass.

a. When the standard/reference sample of glass is suspended in the liquid medium, what

does this say about their densities? The standard/reference sample and liquid medium have the same/similiar density.

b. If the evidence sample of glass is now added to the liquid medium and it also is

suspended, what does this say? The evidence sample, standard/reference sample, and the liquid medium all have the same/similar density; therefore, the evidence is the same kind of glass as the standard/reference glass sample.

c. And if the evidence sample floats on top of the liquid medium?

The evidence sample is less dense than the liquid medium and therefore not the same density as the standard/reference sample and not the same kind of glass.

d. And if the evidence sample sinks to the bottom?

It is more dense than the medium and not the same density or kind of glass. 31. What is the Immersion Method used for?

It is used to determine the refractive index (RI) of a glass fragment.

a. When the evidence sample is immersed in the liquid oil medium and the Becke Line around the sample disappears, what does this say about their refractive indices?

The evidence and the liquid oil have the same RI. Since the RI of the liquid will be known, we now know the RI of the glass.

b. What is the benefit of using the GRIM-3 for RI determination? The analyst can view a large image of the glass fragment to see the Becke line disappear, and the computer automatically adjusts the temperature of the oil and calculates the precise RI at the match point.

32. What is the difference between the radial and the concentric cracks?

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Radial cracks radiate out from the center of impact like spokes on a wheel. Concentric cracks form circles around the center of the impact.

a. Which cracks form first? Radial b. On what side of the glass do they form? Reverse (opposite) side of the impact force

c. Which cracks form second? Concentric

d. On what side of the glass do they form? On the same side as the impact force

e. What is the 3R Rule used for? Used to determine the direction of impact force on glass

f. State the 3R Rule:

Radial cracks form a Right angle on the Reverse side of the force. g. The term “right angle” means ( PERPENDICULAR or PARALLEL ).

h. What happens on the concentric edges of glass?

Concentric cracks form a right angle on the same side of the force 33. When given multiple gunshot penetrations, how do you determine which shot was first?

Fractures from the first impact act as barriers stopping fractures from the second impact. Look for radial fracture lines that abruptly stop when coming in contact with radial fractures from the first impact.

34. Which side ( ENTRANCE or EXIT ) of the glass will a high-velocity projectile, such as a

bullet or bb gun pellet, leave a wider hole?

35. What is the only way to link two glass fragments to a common source? By physically matching the evidence glass to the broken glass from the crime scene like a puzzle.

36. If there is a possibility that glass fragments can be pieced together for an individual fit, how

should the glass be collected? All the glass found at the scene and all the glass from the suspect needs to be collected.

37. If an individual fit is not possible, what glass should be collected?

A representative sample of broken glass from the scene and all the glass from the suspect needs to be collected.

38. What containers are best suited for collection of glass?

Packaged in solid containers to avoid further breakage.

39. If a suspect’s shoes and/or clothing is to be collected for glass fragments, how should it be packaged?

The shoes should be individually wrapped in paper and the clothing in different paper. Unit 7: Hair and Fiber Analysis – Trace Evidence: Hair Unit Review 11

1. What are the 3 layers of the hair shaft? Cuticle, cortex, medulla 2. What 3 patterns describe the scales of the cuticle? Imbricate, coronal and spinous and

isodiametric in deer Which pattern is found in humans? imbricate

3. What is the main body of the hair shaft called? cortex

4. What are the 3 medullary patterns? Continuous, interrupted and fragmented Which type is found in Caucasians, Negroids and Mongoloids? Most humans have a fragmented medulla or no medulla at all except Mongoloids who may have a continuous medulla.

5. What is the predominant feature of the hair shaft in humans? cortex In animals? medulla

6. What are the 3 phases of hair growth? Describe the root bulb in each. Anagen phase: growth phase; may last up to six years. The root is attached to the follicle for continued growth giving the root bulb a flame-shaped appearance. Catagen phase: transition phase where hair growth slows. May last up to 2 – 3 weeks and roots take on an elongated appearance as they are pushed out of the follicle Telogen phase: hair growth ends, root takes on a club-shaped appearance. Over 2 to 6 months hair is pushed out of the follicle and naturally shed.

7. During which phase will hairs forcibly removed have the follicular tag? Anagen phase

8. What is the significance of the follicular tag? Contains nuclear DNA which can be used for individualization

9. When will a hair found at the scene show class characteristics and when will it show individual characteristics? Hair will always show class characteristics unless the follicular tag is intact and nuclear DNA can be obtained

10. List and describe the three main differences between human and animal hairs. Pigment: In humans, remains constant in its color and pigmentation throughout the length of the shaft and in animals it often exhibits rather rapid and radical color changes Medulla: In humans, thin, taking up no more than 1/3 of the hair shaft diameter; amorphous. In animals, very wide; its structure is very regular and well-defined (with certain patterns) Scale pattern: Imbricate in humans; usually spinous or corona in animals

11. What factors are used for comparison of hair in the crime lab? Criminalists look at the color, length and diameter. They look at the presence or absence of the medulla. They also consider the distribution, shape and color of the pigments.

12. What others questions can be determined from hair examination? (p. 419 – 420) What part of the body did it come from? What race is the individual? Age and Sex can only be determined if the follicular tag (nuclear DNA) is present. Whether the hair was forcibly removed. Hair can only be individualized if the follicular tag is present.

13. What is mitochondrial DNA and where is it found? Mitochondrial DNA is passed from mother to child and does not show individual characteristics. It is found in the hair shaft.

14. What is a good sample size for hairs obtained from the head? 50 full length hairs

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15. Why is this size sample necessary? ensures a representative sampling 16. What is the recommended sample size for obtaining hair from the pubic region? 2 dozen

hairs

Trace Evidence: Fiber Unit Review 1. What are the two major categories of fibers? natural and man-made 2. What are natural fibers derived from? plants (cotton, hemp) and animals (wool-sheep; silk-

worm; furs; pelts) 3. What is the most common natural fibers encountered in the crime lab? animal hairs 4. What is the most common natural plant fiber? Cotton

5. What are the two kinds of man-made fibers? Regenerated from raw materials (rayon,

acetate, triacetate) = RRAT; Synthetic from chemicals (nylon, acrylic, polyester) = SNAP.

6. What is the relationship between macromolecules, polymers, monomers and synthetic fibers? Chemicals that make up synthetic fibers are composed of molecules (monomers) which when joined together form polymers. They are referred to as “macromolecules” because of their large size.

7. What are some microscopic characteristics examined and used to compare fibers? First compared for color and diameter using the comparison microscope. Other features include, lengthwise striations (lined markings), and the pitting of the fiber’s surface with delustering particles used to reduce shine.

8. Name the five cross-sectional shapes of fibers. round, trilobal, dumbbell, flat, and multi-lobed

9. Define the following: a. Polarized light microscopy - determines birefringence difference between two refractive

indices using polarized light. Depending on the class of fiber, each polarized plane of light will have a characteristic index of refraction.

b. Birefringence - A useful physical property of fibers of fibers that many manufactured fibers exhibit double refraction or “birefringence”

c. FTIR Fourier Transform Infrared Spectroscopy - analysis of a fiber’s chemical

composition based on its ability to absorb light at different wavelengths Infrared spectrophotometry is a rapid and reliable method for identifying the generic class of fibers, as does the polarizing microscope

d. UV-Visible Microspectrophotometry - distinguishes slight/subtle color differences based

on absorption of light at different wavelengths; Convenient way to analyze colors of fibers; Nondestructive and can be carried out with a small sample; A more detailed analysis of the fiber’s dye composition would be obtained through a chromatographic separation.

10. What is the significance of Fiber Evidence? Shows there was contact between the suspect

(perpetrator) and the victim… a link between the suspect and the crime (Locard’s Exchange Principle). How does it show class characteristics and individual characteristics? Almost always shows class characteristics unless the edges from a torn fiber can be pieced together.

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11. How is Fiber Evidence collected and preserved? Relevant articles of clothing should be packaged carefully in separate paper bags, using clean forceps and bindles.

Unit 8: Metals, Paint, Soil, and Impressions 1. Alpha ray – Radiation compound of helium atoms minus their orbiting electrons 2. Atomic mass – The sum of the number of protons and neutrons in the nucleus of an atom 3. Atomic number – The number of protons in the nucleus of an atom 4. Beta ray – Radiation composed of electrons 5. Continuous spectrum – A type of emission spectrum showing a continuous band of colors

all blending into one another 6. Density-gradient tube – A glass tube filled from bottom to top with liquids of successively

lighter densities; used to determine the density distribution of soil 7. Electron – A negatively charged particle that is one of the fundamental structural units of the

atom 8. Electron orbital – The path of electrons as they move around the nuclei of atoms; each

orbital is associated with a particular electronic energy level 9. Emission spectrum – Light emitted from a source and separated into its component colors

or frequencies 10. Excited state – The state in which an atom absorbs energy and an electron moves from a

lower to a higher energy level 11. Gamma ray – A high-energy form of electromagnetic radiation 12. Isotope – An atom differing from another atom of the same element in the number of

neutrons in its nucleus 13. Line spectrum – A type of emission spectrum showing a series of lines separated by black

areas. Each line represents a definite wavelength or frequency 14. Mineral – A naturally occurring crystalline solid 15. Neutron – A particle with no electrical charge that is one of the basic structures in the nucleus

of an atom 16. Proton – A positively charged particle that is one of the basic structures in the nucleus of an

atom 17. Pyrolysis – The decomposition of organic matter by heat 18. Radioactivity – The emission of high-energy subatomic particles that accompanies the

spontaneous disintegration of unstable nuclei

***Know the Paint Matching Terms too

19. Be able to calculate number of protons, neutrons, and electrons using “APE MAN”

20. What 3 features of paint can be examined using a stereoscope: a. color b. surface texture c. color layer sequence

21. Where are the protons and neutrons found? Nucleus

22. Where are the electrons found? Electron cloud orbitals

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23. Using pyrolysis gas chromatography, emission spectrometry and neutron activation analysis, what can we identify in paint? The elemental composition of the color pigmentation, chemical composition of the binder and solvent.

24. Neutron Activation Analysis is a non-destructive method using gamma ray emission to identify the elemental composition of evidence.

25. List 4 class characteristics of shoe impressions: a. color b. style c. brand d. size

26. Paint is composed of pigmentation color and binders dissolved in a solvent. 27. PDQ can tell us the make, model, and year of the vehicle a paint chip sample came from. 28. Soil must first be dried completely before examining and comparing its color and texture. 29. Three types of impressions: a. Patent – visible, 2D, on a hard surface (photograph w/ruler & electrostatic lift) b. Latent – hidden, 2D, on a hard or semi-hard surface (photograph w/ruler & chemical or physical development_ c. Plastic – visible, 3D, in snow or sand, soil (photograph w/ruler & cast w/dental stone or plaster of Paris

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