Forensic Physics
Microscopy, forensic imaging, density and refractive index, glass, paint and soil trace evidence, impression marks and accident reconstruction.
- 99hours
- 33topics
- 10modules
Light, Photons and the Forensic Spectrum
The physics of light as it lands in a forensic laboratory: the electromagnetic spectrum from gamma through radio with the photon model, the forensic-laboratory light sources (tungsten-halogen, mercury vapour, xenon arc, monochromatic lasers, Polilight + Crime-lite alternate-light sources), and the light-matter interactions that drive every optical examination (absorption, transmission, reflection, scattering, fluorescence, phosphorescence).
Start module- Light, Photons and the Forensic EM SpectrumThe electromagnetic spectrum from gamma to radio, the photon model E = hν, and how each band, from X-ray to infrared, is used in forensic work.13 min
- Forensic Light Sources and Alternate Light ExaminationThe light sources a forensic lab uses, from tungsten-halogen to lasers and ALS platforms like Polilight, and how wavelength choice reveals evidence.13 min
- Light-Matter Interaction: Absorption, Reflection, FluorescenceWhy bloodstains, fibres and prints show up under certain light: absorption, reflection, scattering and fluorescence explained.13 min
Forensic Microscopy
The microscopy stack that anchors trace-evidence and biological-fluid examination: optical fundamentals (magnification, resolution, numerical aperture, Koehler illumination, parfocality), the stereo and comparison microscopes used at every bench, polarising and fluorescence microscopes for anisotropic and labelled samples, and the electron microscopy (SEM, TEM, EDS) that delivers GSR particle confirmation and paint-layer elemental mapping.
Start module- Microscopy Fundamentals: Magnification, Resolution and NAThe optics behind forensic microscopy: magnification, resolution, numerical aperture and the ISO/ASTM calibration workflow courts require.13 min
- Stereo Microscope and Comparison MicroscopeThe stereo microscope for sample triage and the comparison microscope for matching tool marks, bullets and hair side by side.13 min
- Polarising and Fluorescence MicroscopesHow the polarising microscope identifies fibres and minerals, and the fluorescence microscope finds sperm cells and tagged samples.13 min
- Electron Microscopy: SEM, TEM and EDSHow SEM, TEM and EDS confirm gunshot residue and reveal fibre and pigment ultrastructure beyond what light microscopes can show.14 min
Forensic Photography and Imaging
How a forensic photograph becomes courtroom evidence: photography fundamentals (sensors, lenses, exposure, depth of field, perspective control, ring-flash and oblique lighting), the crime-scene workflow (overall + mid-range + close-up + scale + chain of custody), specialised imaging (UV-reflectance, IR-reflectance + transmittance, ALS-assisted, laser-induced fluorescence, infrared luminescence), and digital evidence integrity (RAW vs JPEG, EXIF metadata, hashing, the Daubert + Frye + BSA 2023 § 65B admissibility frames).
Start module- Forensic Photography: FundamentalsThe camera basics behind forensic photography: sensors, lenses, aperture, shutter speed and the standards that keep photos admissible.13 min
- Crime-Scene Photography WorkflowThe four-tier scene photography protocol, from wide establishing shots to close-ups with a scale, and what the photo log must record.13 min
- Specialised Imaging: UV, IR, Laser and ALSHow UV, IR, laser and alternate light imaging reveal bruises, hidden writing and latent prints invisible under normal light.14 min
- Digital Imaging Evidence and Court AdmissibilityHow digital forensic images are captured, hashed for integrity, and enhanced within limits to stay admissible in court.14 min
Density, Refractive Index and Polarimetry
The three physical measurements that drive trace-evidence comparison: density (sink-float, density-gradient column, pycnometry, hydrostatic weighing), refractive index (Becke-line, GRIM-3 hot-stage automated phase-contrast, immersion-oil method, the Locke 1985 forensic protocol), and polarimetry (optical rotation, sucrose and drug analysis, the saccharimeter and Laurent polarimeter).
Start module- Density Measurement: Forensic MethodsHow forensic labs measure density with sink-float tests and gradient columns to compare glass, soil and plastic samples.13 min
- Refractive Index: Becke Line, GRIM and Mettler Hot StageHow a glass fragment's refractive index is measured using the Becke line, the GRIM instrument and a hot stage.13 min
- Polarimetry and Optical Rotation in Forensic AnalysisHow polarimetry measures a substance's optical rotation to check purity and distinguish mirror-image drug and sugar forms.13 min
Glass Evidence
The forensic physics of glass from cradle to courtroom: glass types and manufacture (soda-lime float, borosilicate, tempered, laminated, bullet-resistant, automotive windshield + side glass), fracture analysis (radial vs concentric cracks, Wallner lines, conchoidal hackle, direction-of-force + sequence-of-impact reconstruction, the R v. Hoey 2007 glass-fragment debate), and comparison casework (RI matching via GRIM, density gradient, LA-ICP-MS elemental fingerprinting via the ASTM E2927 standard).
Start module- Glass: Types, Properties and ManufactureThe main glass types, from float and tempered to laminated and bullet-resistant, and what sets each apart forensically.13 min
- Glass Fragmentation and Direction-of-Force AnalysisHow fracture lines, Wallner lines and the 3R rule reveal the direction and sequence of forces that broke a piece of glass.14 min
- Glass Comparison: RI, Density and LA-ICP-MSHow forensic labs compare glass fragments by refractive index, density and trace-element makeup using LA-ICP-MS.14 min
Soil and Earth Evidence
Soil as a forensic trace-evidence class: composition and classification (mineral fraction, organic fraction, water + air content, USDA texture triangle, the Munsell colour system), examination techniques (density-gradient separation, particle-size distribution, mineralogy via polarising microscopy and XRD, forensic palynology, forensic diatomology), and comparison casework with statistical inference (the Murray-Tedrow framework, the FBI Soil Examination Unit protocols, the ENFSI European geological evidence guideline).
Start module- Soil Composition, Classification and the Munsell SystemWhat soil is made of, how it is classified by texture, and how the Munsell system records colour for comparison.13 min
- Soil Examination: Density Gradient, Mineralogy and PalynologyThe lab methods for examining soil evidence: density-gradient columns, mineral analysis, and pollen studies.14 min
- Soil Comparison Casework and Statistical InferenceHow questioned and known soil samples are compared, the statistics behind a match, and why soil evidence is a likelihood, not proof.13 min
Paint, Pigment and Coating Evidence
Paint as the highest-volume trace-evidence class after fibres: composition (binder + pigment + extender + additive + solvent), paint types (automotive OEM + refinish, architectural latex + alkyd, industrial epoxy + polyurethane, art-and-restoration pigments), layer examination (microtome cross-section, comparison microscopy, FTIR microspectroscopy, pyrolysis GC-MS), and the comparison databases (RCMP Paint Data Query PDQ, ENFSI European Collection of Automotive Paints EUCAP) that drive automotive hit-and-run casework.
Start module- Paint Composition, Types and Binder ChemistryWhat paint is made of, the binders and pigments used, and how layered vehicle paint becomes forensic trace evidence.13 min
- Paint Layer Examination: Cross-Section, FTIR and Py-GC-MSHow forensic labs examine paint chip layers using cross-sections, FTIR and Py-GC-MS to match paint to a vehicle.14 min
- Paint Databases (PDQ, EUCAP) and Comparison CaseworkHow paint databases like PDQ and EUCAP identify a vehicle's make and model from a paint chip left at a hit-and-run.13 min
Building Materials, Tool Marks and Impression Evidence
The patterned-evidence and material-class topics that close the trace-physics arc: cement + plaster + brick + mortar examination (composition, comparison via XRD + FTIR), tool-mark fundamentals (the AFTE class + subclass + individual frame, striated vs impressed marks, mechanics of mark formation), tool-mark comparison (comparison microscopy, IBIS-class 3D imaging, the PCAST 2016 challenge to subjective comparison), and impression evidence (footprints, tyre marks, the SWGTREAD standard, casting with Dental Stone + ESLA electrostatic dust-print lift).
Start module- Cement, Plaster and Building-Material EvidenceHow cement, plaster and brick traces are examined and compared to place a suspect at a break-in or blast scene.12 min
- Tool Marks: Fundamentals, Striations and ImpressionsHow tools leave striated and impressed marks, how class and individual features differ, and how a mark is linked to a tool.13 min
- Tool-Mark Comparison Microscopy and 3D ImagingHow tool marks are compared under the microscope and with 3D imaging, and how examiners report whether two marks match.13 min
- Impression Evidence: Footprints, Tyre Marks and CastingHow footprints and tyre marks are photographed, lifted and cast, then compared to link a suspect to a scene.13 min
Restoration of Erased Marks, Vehicle and Accident Physics
Three high-value applied-physics topics: restoration of obliterated serial numbers (chemical etching via Fry's reagent + Davis reagent, magnetic-particle method, electrolytic, ultrasonic cavitation, scanning electron + neutron-induced X-ray fluorescence), vehicle examination (paint cross-section, headlight + side-marker bulb hot-vs-cold filament analysis, tyre-print individualisation, the Daubert-grade vehicle-component database), and accident-reconstruction physics (velocity from skid marks, momentum conservation in two-vehicle collisions, the SAE J1739 + IRTE reconstruction frameworks, biomechanics of pedestrian impact).
Start module- Restoration of Erased Serial NumbersHow a filed-off serial number is restored using chemical etching, magnetic particle inspection and other recovery methods.13 min
- Vehicle Examination: Paint, Glass, Tyre, Headlight FilamentHow a vehicle is examined after a hit-and-run using paint, glass, tyre marks and the headlight filament test.13 min
- Accident Reconstruction Physics: Velocity, Momentum and Skid MarksHow investigators calculate vehicle speed and reconstruct a crash using skid marks, momentum and impact physics.14 min
Forensic Acoustics, Engineering and Emerging Physics
The frontier of forensic physics: acoustics (gunshot acoustic analysis with muzzle blast + shock-wave separation, environmental-recording authentication, the ENF electrical-network-frequency timestamping), forensic engineering (materials testing, fractography, fatigue + creep failure analysis, the NIST-NCSTAR WTC reports as casework templates), and emerging physics (terahertz imaging for concealed-weapon and ink-layer detection, hyperspectral imaging for documents + bloodstain ageing, quantum sensing pilots, AI-assisted image and pattern analysis with the ENFSI 2023 AI position paper).
Start module- Forensic Acoustics and Gunshot Acoustic AnalysisHow sound recordings help locate a shooter by gunshot acoustics and verify whether an audio recording is authentic.13 min
- Forensic Engineering: Failure Analysis and FractographyHow engineers read a fracture surface to work out why a part or structure failed, from plane crashes to building collapses.13 min
- Emerging Physics: Terahertz, Hyperspectral, Quantum and AI ImagingNew tools reaching forensic physics: terahertz imaging, hyperspectral cameras, quantum sensors and AI pattern matching.14 min