Journal Published Online: 01 January 2005
Volume 50, Issue 1

Deducing Drop Size and Impact Velocity from Circular Bloodstains



An experimental study was done to determine the diameter and velocity of blood drops falling on a surface by measuring the size of bloodstains they produced and counting the number of radial spines projecting from them. Bloodstains were formed by releasing drops of pig blood with a range of diameters (3.0–4.3 mm) and impact velocities (2.4–4.9 m/s), onto four different flat surfaces (glass, steel, plastic, paper) with varying roughness (0.03–2.9 µm). High-speed photography was used to record drop impact dynamics. Bloodstain diameters and the number of spines formed around the rim of stains increased with impact velocity and drop diameter. Increasing surface roughness reduced stain diameter and promoted merging of spines, diminishing their number. Equations are presented that explicitly relate drop diameter and impact velocity to measurements of stain diameter and number of spines.

Author Information

Hulse-Smith, L
Princess Margaret Hospital, Toronto, Ontario, Canada
Mehdizadeh, NZ
University of Toronto, Toronto, Ontario, Canada
Chandra, S
University of Toronto, Toronto, Ontario, Canada
Pages: 10
Price: $25.00
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Stock #: JFS2003224
ISSN: 0022-1198
DOI: 10.1520/JFS2003224