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FORENSIC 3 > CHAPTER 6-8 > Flashcards

CHAPTER 6-8 Flashcards

1
Q

V-is important as physical evidence because it breaks and pieces are scattered at the crime scene and on the suspect.

A

GLASS

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2
Q

-is important as physical evidence because it breaks and pieces are scattered at the crime scene and on the suspect.

A

GLASS

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3
Q

-The evidence maybe fragments of a headlight leads found at the scene of a hit and run accident, window glass from the scene of robbery, or glass through which a bullet was fired.

A

GLASS

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3
Q

– This refers to a supercooled liquid which possesses high viscosity and rigidity.

A

GLASS

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3
Q

-It is a non – crystalline inorganic substance.

A

GLASS

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3
Q

-is usually composed of oxides like SiO (silica), B O (boric oxide), P O (phosphorous pentoxide).

A

GLASS

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4
Q

-It is made of silica sand and other metallic oxides.

A

GLASS

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5
Q

-This may contain incidental impurities and the presence of these substances is invaluable for the identification and comparison of glass by spectrographic analysis.

A

GLASS

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6
Q

______ like window and plate which are made in mass production is fairly uniform in composition.

A

GLASS

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7
Q

is the most important oxide.

A

SILICA

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8
Q

-It is the base of commercial glasses.

A

SILICA

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8
Q

is for fluxing, durability and reduction of viscosity.

A

Oxide

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9
Q

has also presence of trace elements which may be sufficient to establish or negate the fact of a common source for two samples of glass.

A

Gas

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10
Q
  • base of commercial glass
A

SILICA

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11
Q

–basic foundation of glass

A

SILICA

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12
Q

SILICA chemical name

A

SiO2

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13
Q

SODA name

A

Na2O

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14
Q

-acts as flux for silica

A

SODA

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15
Q

-gives the glass chemical durability which it otherwise lack because of the water – soluble Na2O

A

LIME

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16
Q

Lime name

A

CaO

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17
Q

-present as impurity or substitute for CaO

A

MAGNESIS

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18
Q

MAGNESIS name

A

MgO

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19
Q

–substitute for lime

A

MAGNESIS

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20
Q

-gives the glass greater chemical durability lower coefficient of expansion, and greater freedom from devitrification

A

ALUMINA

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21
Q

ALUMINA name

A

Al2O2

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22
Q

-for chemical durability and resistance to devitrification

A

POTASH

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23
Q

–strong chemical
–for high rise building

A

POTASH

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24
Q

POTASH name

A

KO

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25
Q

3R RULES

A
  1. POINT OF IMPACT
  2. RADIAL FRACTURE
  3. CONCENTRIC FRACTURE
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26
Q

-The most important problem commonly referred to a forensic chemist is the comparison of two or more samples of glass.

A

ANALYSIS OF GLASS

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27
Q

– an instrumental method of analysis which determines the presence of trace elements.

A

SPECTROGRAPHIC TEST

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28
Q

-Shows the constituent elements of glass.

A

SPECTROGRAPHIC TEST

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29
Q

-It will not give sufficient information to establish is the origin of the samples examined.

A

SPECTROGRAPHIC TEST

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29
Q

-A rapid examination and an adequate method for glass analysis since it requires only a small amount of sample.

A

SPECTROGRAPHIC TEST

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29
Q

-In the absence of trace elements, it may be difficult to determine whether two samples of common type of glass are identical.

A

SPECTROGRAPHIC TEST

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30
Q

-If similar trace elements are found of both samples it is obvious they come from the source.

A

SPECTROGRAPHIC TEST

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30
Q

– not as effective as the spectrographic analysis.

A

X – RAY DIFFRACTION TEST

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31
Q

-It determines the type of pattern of glass.

A

X – RAY DIFFRACTION TEST

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31
Q

-The type of pattern depends upon the composition of glass.

A

X – RAY DIFFRACTION TEST

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32
Q

– the most sensitive method of determining differences of composition in glass samples and depends upon the study of the physical properties of glass.

A

PHYSICAL PROPERTIES EXAMINATION

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33
Q

-Properties like specific gravity and density, refractive index.

A

PHYSICAL PROPERTIES EXAMINATION

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34
Q

-Density and refractive index can be measured with great accuracy.

A

PHYSICAL PROPERTIES EXAMINATION

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35
Q

is an especially important physical property from the viewpoint of the forensic chemist.

A

Density or specific gravity

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36
Q

– a rapid and convenient method of determining the density of small glass fragments.

A

FLOTATION METHOD

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37
Q

-Procedure and principle are the same as in soil

A

FLOTATION METHOD

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38
Q

– method used to measure the refractive index of a glass.

A

IMMERSION METHOD

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39
Q

-It is difficult to distinguish between two samples of glass by density and refractive index.

A

IMMERSION METHOD

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40
Q

-It may be mentioned that two glass from independent sources can vary conceivably have the same index of refraction or the same density but it is quite improbable that they would have both index of refraction and density the same.

A

IMMERSION METHOD

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41
Q

– determines the differences in the appearance of the fluorescent thus indication of physical and chemical differences.

A

ULTRAVIOLET LIGHT EXAMINATION

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42
Q

– optical glass and other fine glasswares are usually _____

A

POLISH MARKS

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43
Q

-In the _____ of glass fine marks are often left on the surface which can sometimes serve as a basis of comparison.

A

POLISH MARKS

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44
Q

The surface is cleaned with alcohol and then etched by spraying with ________. The act is permitted to remain on the surface for several minutes. The glass is again washed with alcohol and dried. If the surface is illuminated by oblique tight, a photograph can be made to show the polish marks.

A
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45
Q

The surface is cleaned with alcohol and then etched by spraying with 20 to 25% hydrofluoric acid. The act is permitted to remain on the surface for several minutes. The glass is again washed with ______ and dried. If the surface is illuminated by oblique tight, a photograph can be made to show the polish marks.

A

alcohol

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46
Q

____ first bends a little owing to its elasticity

A

glass

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47
Q

When the limit of _______ is reached the glass breaks along radial lines starting from the point where the portion or surface which is more subjected to stretching by bending.

A

elasticity

48
Q

represent a good percentage of crimes.

A

Hit and run accidents

49
Q

Examination of window fragments in robbery cases is important when there is a question of “as to whether the glass was broken from the outside or inside.”

A

ANALYSIS OF BROKEN WINDOWS

50
Q

Generally, it maybe said that the hole produced by a bullet of a strong charge has the

A

sharpest edges

51
Q

The direction of the blow in case a ______ smashed the window is quite difficult but the principle of radial crack and concentric crack or fracture will apply.

A

fist or stone

52
Q

– states “stress lines on a ________ will be at right angle to the rear side of the glass.”

A

radial crack

53
Q

produced by a low – speed impact such as a rock (left) and by a high – speed projectile such as a bullet (right)

A

Glass fractures

54
Q

– states “stress lines on a __ will be at right angle to the front side”, that is the side from which the blow came rather than the rear side.

A

concentric crack

55
Q

is the reverse of the 3 R’s rule

A

CONCENTRIC CRACK

56
Q

can be examined is near, preferably adjacent to the point of impact.

A

CONCENTRIC CRACK

57
Q

that is now being used in automobiles does not shatter when struck sharply.

A

Laminated glass

58
Q

-Frequently the cracking of safety glass is

A

not complete

59
Q

The ________ does not extend to the side of impact and the spiral cracks do not extend to the other side.

A

radial crack

60
Q

Traces left by a criminal

A

FOOT IMPRESSION AND TOOL IMPRESSION

61
Q

A given impression can only be produced by one object.

A

FOOT IMPRESSION AND TOOL IMPRESSION

62
Q

The evidential value of an impression made by shoe, hand, tool or other articles is based in the theory that no two physical objects are alike and hence that impressions made by such object often is marked by uniquely identifying characteristics.

A

FOOT IMPRESSION AND TOOL IMPRESSION

63
Q

– a strong mark produced by pressure that goes below the surface.

A

IMPRESSION

64
Q

-A stamp, form or figure resulting from physical contact.

A

IMPRESSION

65
Q

-It causes damage to object.

A

IMPRESSION

66
Q

– weak mark made by pressure that stays on the surface.

A

IMPRINT

67
Q

In cases involving footprints, tool marks, tooth impressions, __________ may not serve the purpose.

A

photographic representation

68
Q

Using a mold called ___ can only make a faithful reproduction of these objects.

A

moulage

69
Q

– a faithful reproduction of an impression with the use of casting materials.

A

MOULAGE

70
Q

-It is admitted that _______ cannot reproduce all characteristics of the object under all circumstances but whatever is mission it can be supplied by the photograph.

A

MOULAGE

71
Q

– any material which can be changed from a plastic or liquid state to the solid condition.

A

CASTING MATERIAL

72
Q

For foot impression and tire impression, _______ is the best casting material.

A

PLASTER OF PARIS

73
Q

Sometimes it is desirable to hasten or retard the setting time of the

A

PLASTER OF PARIS.

74
Q

– add one half teaspoonful of table salt to the plaster.

A

HASTENING

75
Q

– add one part of saturated solution of borax to ten parts of water to be used in making the plaster.

A

RETARDING

76
Q

-One teaspoonful of sugar may also be used.

A

RETARDING

77
Q

to give a dried cast greater durability it can be placed in saturated solution of _________ and allow to remain in the solution for some time.

A

sodium bicarbonate

78
Q

– Poor mechanical strength.

A

DRAWBACK OF PLASTER OF PARIS

79
Q

-The fluid plastic flows into all the interstices of the mark but when the cast is removed from the mark the finer details tend to break off

A

DRAWBACK OF PLASTER OF PARIS

80
Q

– used for small impressions as tooth impression, tool impression.

A

WOOD’S METAL

81
Q

-It is a variety of solder with melting 60o to 70°C.

A

WOOD’S METAL

82
Q

-It is made of B – 50%, Pb – 25%, Sn – 12.5% and Cd – 12.5%.

A

WOOD’S METAL

83
Q

– like plasticine and dental composition.

A

PLASTIC MATERIAL

84
Q

is the best casting material for making the cast of tool marks

A

Dental composition

85
Q

DRAWBACK – distorts when remove from the impression since ______ and never did and does not flow to the very interstices of the impressions.

A

PLASTIC MATERIAL

86
Q

– used for human body as cast of hand or face.

A

NEGOCOLL

87
Q

-It is rubbery gelatinous consisting material consisting of colloidal magnesium soap.

A

NEGOCOLL

88
Q

– brown substance used for backing and strengthening the hominid.

A

CELERIT

89
Q

-It is important that the temperature of the negative material should be below 110 F (43.3 C).

A

CAST OF HUMAN BODY

90
Q

-A temperature higher than this will be uncomfortable if not injurious to the subject.

A

CAST OF HUMAN BODY

91
Q

-It is important that the temperature of the negative material should be _____

A

below 110 F (43.3 C).

92
Q

are more satisfactory than plastic materials in this respect since even the most plastic material does not enter into the crevices of all the minute depression.

A

Fluid materials

93
Q

is desirable as the time factor is often of importance.

A

Rapid hardening

94
Q

-Tool impressions may be classified into two general classes

A

a. COMPRESSION MARKS
b. FRICTION MARKS

95
Q

– produced by a single application of the tool in one area of contact.

A

COMPRESSION MARKS

96
Q

single blow of a hammer.

A

COMPRESSION MARKS

97
Q

– these are series of scratches or striations produced by pushing a tool across the surface such as those produced cutters, axe and jimmy.

A

FRICTION MARKS

98
Q

Those produced by such instruments like saw or file that is applied in repeated strokes over the same area. It is hard to identify since one – mark overlaps the other

A

TOOL IMPRESSIONS

99
Q

Those produced by such instruments like axe, hammer, pliers and cutters which touch the area only once in producing the impression.

A

TOOL IMPRESSIONS

100
Q

-Examination of tool impression is done by ________ the purpose of which is to determine or to show that the particular tool made impression in question.

A

comparative examination

101
Q

will in most instances be of great help in the solution of baffling problems involving pieces of metal or metal articles. Robbery, Arson, Murder, Kidnapping, Hit and Run, counterfeiting are examples of this investigation work.

A

METALLURGY

101
Q

– the art of extracting and working on metals by the application of chemical and physical knowledge.

A

METALLURGY

101
Q

– branch of metallurgy that involves the study of the microstructures of metals and alloys.

A
102
Q

-All metals are composed of ____, under the naked eye and when viewed from a distance a metal appears to be homogeneous but when viewed under a metallography microscope the crystal structure is visible.

A

minute grains or crystals

103
Q

All metals are composed of minute grains or crystals, under the naked eye and when viewed from a distance a metal appears to be _____ but when viewed under a metallography microscope the crystal structure is visible.

A

homogeneous

104
Q

-These crystals of the metal are tightly packed.

A

METALLOGRAPHY

105
Q

APPLICATION OF METALLURGY IN CRIMINAL INVESTIGATION

A
  1. ROBBERY
  2. THEFT
  3. HIT AND RUN
  4. BOMB AND EXPLOSION
  5. NAIL EXAMINATION
  6. COUNTERFEIT COINS
  7. RESTORATION OF TAMPERED SERIAL NUMBER or MACRO ETCHING
106
Q

are coins made to imitate the real thing and used for gain.

A

COUNTERFEIT COINS

107
Q

TWO KINDS OF COUNTERFEIT COINS:

A
  1. CAST COINS
  2. STRUCK COINS
108
Q

– coins made in molds.

A

CAST COINS

109
Q

– coins made by striking or stamping method.

A

STRUCK COINS

110
Q

– An impression of genuine coin is taken by use of Plaster of Paris, clay or bronze.

A

CAST COINS

111
Q

-The plaster molds bearing the image of a good coin are filled within a low temperature alloy made with lead or tin.

A

CAST COINS

112
Q

are used for high temperature metals such as copper or silver alloys.

A

Sand molds

113
Q

-It can be easily detected.

A

CAST COINS

114
Q

have poor imitation.

A

CAST COINS

115
Q

-The surface is usually pitted and uneven.

A

CAST COINS

116
Q

-The edge of letterings and designs are rounded instead of sharp.

A

CAST COINS

117
Q

– Made by striking or stamping method.

A

STRUCK COINS

118
Q

-Consists of making an impression of a coin on a metal blank by pressure.

A

STRUCK COINS

119
Q

is done by way of steel dies.

A

Stamping

120
Q

-Often well executed.

A

STRUCK COINS

121
Q

-Its detection is not easy since weight, specific gravity, composition may all be good.

A

STRUCK COINS

122
Q

-Careful comparison of smaller details of the design with those of the genuine should be made.

A

STRUCK COINS

123
Q

Examination of counterfeit coins involves

A

chemical and physical method.

123
Q

is a fluid used to restore tampered serial numbers.

A

Etching fluid

123
Q

are restored by the application of etching liquid.

A

TAMPERED SERIAL NUMBERS

123
Q

-Choice of etching depends on the _____ bearing the original numbers.

A

structure of the metal

FORENSIC 3 (6 decks)

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