Deducing Drop Size and Impact Velocity from Circular Bloodstains.

Presents a study to determine the diameter and velocity of blood drops falling on a surface by measuring the bloodstains they produced and counting the number of radial spines projecting from them. Formation of bloodstains by releasing drops of pig blood with a range of diameters and impact velocities, onto four different flat surfaces with varying roughness; Use of high-speed photography to record impact dynamics; Presentation of equation that explicitly relate drop diameter and impact velocity to measurements of stain diameter and number of spines.