Deducing Drop Size and Impact Velocity from Circular Bloodstains

    Volume 50, Issue 1 (January 2005)

    ISSN: 0022-1198


    Published Online: 1 January 2005

    Page Count: 10

    Hulse-Smith, L
    Princess Margaret Hospital, Toronto, Ontario

    Mehdizadeh, NZ
    University of Toronto, Toronto, Ontario

    Chandra, S
    University of Toronto, Toronto, Ontario

    (Received 28 June 2003; accepted 2 September 2004)


    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.

    Paper ID: JFS2003224

    DOI: 10.1520/JFS2003224

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    Title Deducing Drop Size and Impact Velocity from Circular Bloodstains
    Symposium , 0000-00-00
    Committee E30