Analyzing forensic evidence based on density with magnetic levitation

Area of Science:

• Forensic Science
• Materials Science
• Physics

Background:

• Accurate density determination is crucial for characterizing trace evidence in forensic investigations.
• Traditional methods for density measurement can be time-consuming, expensive, and limited by sample characteristics.
• Developing rapid, accurate, and versatile density measurement techniques is essential for forensic science.

Purpose of the Study:

• To introduce and validate a magnetic levitation (MagLev) method for determining the density of trace objects.
• To assess the feasibility of MagLev for forensic applications, including the analysis of glitter and gunpowder.
• To demonstrate the method's ability to differentiate particles by density and analyze samples within complex matrices.

Main Methods:

• Utilized a custom-built magnetic levitation device comprising two permanent magnets with like poles facing.
• Employed MagLev to measure the density of various trace materials, including glitter and gunpowder.
• Validated the accuracy of MagLev measurements against known densities, achieving a precision of ± 0.0002 g/cm(3).

Main Results:

• MagLev accurately determined the density of diamagnetic trace objects, irrespective of their shape or size.
• The method successfully differentiated glitter particles based on their distinct densities.
• Density determination was feasible even for glitter samples extracted from complex matrices, demonstrating practical applicability.

Conclusions:

• Magnetic levitation provides a rapid, inexpensive, and verifiable means for accurate density determination of trace evidence.
• MagLev is a promising technique for forensic analysis, offering objective and searchable density data.
• The method's versatility supports its application in characterizing diverse forensic materials.