ASTM E2365
Definition
The American Society for Testing and Materials standard for forensic comparison of glass by density; specifies temperature control, calibration, and precision requirements for gradient-column and pycnometric measurements.
- Full title
- Forensic comparison of glass by density
- Methods covered
- Gradient-column and pycnometric measurement
- Requirements set
- Temperature control, calibration, precision
- Issuing body
- ASTM International
Common questions
Why is temperature control so tightly specified for glass density comparison?+
Density measurements, especially with a gradient column, are sensitive to small temperature shifts in the suspension liquid, so E2365 requires controlled conditions to keep readings reproducible enough that two glass fragments from the same source consistently measure as matching.
Can two glass fragments with matching density under E2365 be treated as coming from the same source?+
Matching density is consistent with a common source but is not individually distinguishing on its own, since many glass batches share similar densities; it is typically combined with refractive index and elemental analysis before a stronger association conclusion is drawn.
Related terms
- Bromoform-Bromobenzene System
- The reference liquid mixture used in forensic density-gradient columns and sink-float tests; bromoform (2.890 g/cm³) and bromobenzene (1.495 g/cm³) mix in variable...
- Density
- Mass per unit volume (ρ = m/V), expressed in g/cm³ or kg/m³; a physical property used to compare and discriminate glass, mineral,...
- Density-Gradient Column
- Glass column filled with stepwise layers of liquids of decreasing density (commonly bromoform 2.89 g/cm3 and bromobenzene 1.50 g/cm3 mixed in known...
- DFSS
- Directorate of Forensic Science Services, India; issues the Forensic Laboratory Manual that governs glass and soil examination procedures, including the bromoform-based density...
- ENFSI ENG3-2013
- The ENFSI Glass Expert Working Group guideline for glass comparison casework; specifies the examination sequence, within-source variation requirements, statistical comparison framework, and...
- Hydrostatic Weighing
- Density measurement exploiting Archimedes' principle; the apparent weight loss of a solid submerged in a liquid of known density equals the weight...
- Neutral Buoyancy
- The condition in which a solid object's density exactly matches the density of the surrounding liquid; the object neither sinks nor rises...
- Oscillating-U-Tube Densitometer
- An instrument that measures liquid density from the resonant frequency of a liquid-filled U-shaped tube; precision of ±0.0001 g/cm³, widely used for...
- Pycnometry
- Absolute density measurement using a calibrated-volume flask; the density of a solid is calculated from the mass of liquid displaced when the...
- Sink-Float Test
- Qualitative density screening in which a solid fragment is immersed in a liquid of adjustable density until neutral buoyancy is achieved; the...
- Stokes Settling Formula
- The equation v = 2r²g(ρₛ - ρ_f) / 9η relating the settling velocity of a spherical particle to its radius, the density...