Blood spatters are telltale marks of violent crimes, and have captured the public imagination in shows like Dexter, CSI, and Bones–shows whose cool tech may be less based in reality than special effect. For instance, it’s only just now been worked out how to determine the height from which blood droplets fell. And it didn’t take anything high tech–just a couple of guys in a lab (namely Fred Gittes and Chris Varney from Washington State University) armed with a hinged “clapper” to send the blood flying.
Crime scene investigators have long been able to tell where a blood spatter came from, because elliptical splashes are a dead giveaway. But when the source of the blood has been moved–say, from a sitting to a lying-down position–the analysis can reveal details of the crime itself. This can be critical information because in a complicated court case it could help to know if the victim was sitting, standing, or already on the ground–the data plays into arguments about self defense and other technicalities.
Gittes and Varney performed experiments by scattering “blood” made from Ashanti chicken wing sauce and Ivory dishwashing soap, and then trying to model the behavior. It turns out that a good deal of the math was surprisingly basic, and they came up with a model for working out how high a blood droplet fell from. Their method prevents investigators from drawing the wrong conclusions, because the algorithm self-corrects (the graphs deviate from straight lines if the analysis is wrong.)
Sometimes an important innovation doesn’t require a supercomputer or rocket science–just some brainpower, elbow grease, and wing sauce.
[Image: Flickr user clovenhoof]