Forensic Physics: Glass and Soil Trace Analysis
Published:
Questions
30
Duration
30 min
Faculty-reviewed
30
Updated
03 May 2026
About this mock
This mock covers the glass and soil trace-evidence sections of the FACT Forensic Physics syllabus and the trace-evidence portion of the UGC-NET Forensic Science paper. Thirty questions across the techniques and interpretation principles every BSc and first-year MSc forensic-science student must lock in: refractive-index measurement of recovered glass fragments by the GRIM 3 hot-stage / oil-immersion method, density comparison by sink-float and the density-gradient column, elemental analysis by LIBS, micro X-ray fluorescence (muXRF), SEM-EDX, and laser-ablation ICP-MS, fracture-pattern interpretation (Wallner lines, hackle marks, conchoidal / crater fracture, the 4R rule for radial cracks, sequencing two impacts on a single pane), the Bayesian / likelihood-ratio framework for reporting glass evidence, and the corresponding suite of soil techniques: colour comparison against the Munsell soil-colour chart in moist and dry states, mineral identification by polarised-light microscopy, particle-size (texture) analysis, soil pH and loss-on-ignition for organic content, density-gradient comparison of soil banding, and the biological provenance markers — pollen, spores, and diatoms — together with their preparation by Erdtman acetolysis and the diatom test for drowning.
It is pitched at BSc and first-year MSc forensic-science students at NFSU, LNJN-NICFS, and other Indian universities, FACT and FACT Plus aspirants, and UGC-NET candidates who need the trace-evidence physics sections locked in before tackling case law and casework reconstruction. This is the introductory-tier mock for the topic — definitions, instrument identification, and the most-asked interpretation rules.
Topics covered:
- Refractive index by GRIM 3 oil-immersion / hot-stage Becke-line method (ASTM E1967)
- Float-glass tin side vs air side; UV fluorescence and surface-vs-bulk RI
- Density by sink-float and the density-gradient column
- Elemental analysis: LIBS, muXRF (ASTM E2926), SEM-EDX, LA-ICP-MS (ASTM E2927)
- Fracture features: Wallner lines, hackle / rib marks, conchoidal / crater fracture
- Direction of force (4R rule for radial cracks) and sequence of multiple impacts
- Soil colour with the Munsell chart (moist and dry, hue / value / chroma)
- Soil density-gradient comparison; particle-size (sand / silt / clay) texture
- Soil chemistry: pH at 1:2.5 with water; loss-on-ignition for organic content
- Mineral identification by polarised-light microscopy (RI, birefringence, extinction, pleochroism, habit)
- Forensic palynology — pollen and spores by Erdtman acetolysis
- Diatoms and the drowning test
- Geographic provenance limitations and the Bayesian / likelihood-ratio framework
- Collection and packaging: paper bindles (druggist fold), control samples, contamination
Each question carries a detailed 220+ word explanation citing standard references — Saferstein's Criminalistics, Houck and Siegel's Fundamentals, James and Nordby's Forensic Science, the Curran / Hicks / Buckleton monograph on the Forensic Interpretation of Glass Evidence, Pye's Geological and Soil Evidence, Murray's Evidence from the Earth, the SWGMAT glass guideline, ASTM E1492, E1967, E2926 and E2927, the Munsell soil-colour-chart user guide, the Mildenhall-Wiltshire-Bryant palynology review, and Pollanen on forensic diatomology. Allow 30 minutes; the explanations are long enough to use as study notes by themselves.
Sources & references
Questions in this mock are written and verified against the following sources. Citations are recorded per question and shown in the explanation after submission.
- cited in 5 questions
Saferstein, Richard — Criminalistics: An Introduction to Forensic Science
Chapter on Glass and Soil (density-gradient tube)
- cited in 5 questions
Pye, Kenneth — Geological and Soil Evidence: Forensic Applications
Chapters on interpretation, provenance limitations, and case examples
- cited in 3 questions
Houck, Max M. & Siegel, Jay A. — Fundamentals of Forensic Science
Trace evidence chapter — glass density measurement (sink-float and density-gradient column)
- cited in 2 questions
James, Stuart H. & Nordby, Jon J. — Forensic Science: An Introduction to Scientific and Investigative Techniques
Chapter on glass fracture features (hackle and Wallner lines)
- cited in 2 questions
Mildenhall, D.C.; Wiltshire, P.E.J.; Bryant, V.M. — 'Forensic palynology: Why do it and how it works' (Forensic Science International, 2006)
Section on sample preparation (Erdtman's acetolysis) and microscopic identification
- cited in 2 questions
Curran, James M.; Hicks, Tacha N.; Buckleton, John S. — Forensic Interpretation of Glass Evidence
Chapters on the Bayesian / likelihood-ratio framework, transfer and persistence
- cited in 2 questions
ASTM E2927 — Standard Test Method for Determination of Trace Elements in Soda-Lime Glass Samples Using LA-ICP-MS for Forensic Comparisons
Scope and rationale (independent discrimination from elemental composition)
- cited in 1 question
Goldstein, Joseph I. et al. — Scanning Electron Microscopy and X-Ray Microanalysis
Chapters on the principles of SEM imaging and EDX quantitative analysis
- cited in 1 question
Munsell Color Company — Munsell Soil Color Charts
User guide (recording moist and dry colour as hue / value / chroma)
- cited in 1 question
SWGMAT — Glass Examinations: Standard Guide for Forensic Comparison of Glass
Sections on multi-property comparison and the role of frequency / rarity data
- cited in 1 question
ASTM E2926 — Standard Test Method for Forensic Comparison of Glass Using Micro X-ray Fluorescence (muXRF) Spectrometry
Scope and applicability (non-destructive elemental comparison of glass)
- cited in 1 question
Sharma, B.R. — Forensic Science in Criminal Investigation and Trials
Chapter on Glass Evidence (4R rule for radial cracks; 3R rule for concentric)
- cited in 1 question
Murray, Raymond C. — Evidence from the Earth: Forensic Geology and Criminal Investigation
Chapter on physical examination of soils (texture and particle-size analysis)
- cited in 1 question
Pollanen, Michael S. — Forensic Diatomology and Drowning
Monograph (Elsevier) — chapters on the diatom test, methodology, and limitations
- cited in 1 question
ASTM E1492 — Standard Practice for Receiving, Documenting, Storing, and Retrieving Evidence in a Forensic Science Laboratory
Sections on documentation and packaging of trace evidence
- cited in 1 question
ASTM E1967 — Standard Test Method for the Automated Determination of Refractive Index of Glass Samples Using the Oil Immersion Method and a Phase Contrast Microscope
Scope and procedure (oil-immersion / hot-stage Becke-line method)
How our mocks are built
Questions are written and edited by the ForensicSpot team and cited from peer-reviewed forensic textbooks, official syllabi and primary case law. Each one is verified before publishing. Detailed explanations show after you submit, so the test stays a real test. See a mistake? Tell us.
Common questions
What does the Forensic Physics: Glass and Soil Trace Analysis mock cover?+
This mock covers the glass and soil trace-evidence sections of the FACT Forensic Physics syllabus and the trace-evidence portion of the UGC-NET Forensic Science paper. Thirty questions across the techniques and interpretation principles every BSc and first-year MSc forensic-science student must lock in: refractive-index measurement of recovered glass fragments by the GRIM 3 hot-stage / oil-immersion method, density comparison by sink-float and the density-gradient column, elemental analysis by L
How many questions and how long is the test?+
30 multiple-choice questions, 30 minutes total. Difficulty: easy. Tier: Free.
Who is this mock for?+
Forensic science students and aspirants who want timed, exam-style practice with explanations and verified source citations on Forensic Physics, FACT, NET. Useful for postgraduate entrance preparation and for BSc / MSc forensic students testing their recall under time.
Are the questions reviewed?+
Yes — 30 of 30 questions are faculty-reviewed. Each question carries a verified source citation.
Do I need an account to take this mock?+
Yes, a free ForensicSpot account is required to start a timed attempt — this lets you save progress, see per-question explanations after submission, and track your topic-level performance over time.