Forensic Science Students Study Blood Spatter

Bloodstain pattern analysis is a powerful forensic tool used in crime scene investigations. If the investigator understands the dynamics of an altercation, how blood behaves when it exits the body, and how it reacts when it contacts a surface, then an attempt can be made to understand what happened and to determine if a crime occurred. 

The trained forensic scientist looks at the patterns made by shed blood and tries to determine what did and/ or did not happen. Interpreting the bloodstain patterns involves physical measurement of blood droplets, pattern recognition using known photographs or experiments, the use of trigonometry, and knowledge of the physics of motion. 

Katie and Chrissy are examining their blood drop test sheet to determine which drops to measure as examples of blood droplet hitting a surface from a specified height at a specific angle.

Vivian enters the length and width of droplets previously measured into a data table. The data will eventually be compiled in an Excel spreadsheet designed to determine the angle of incidence for the blood droplet and the height from which the blood droplet originated.

Jesse measures a different sample of blood droplets.

Nick is completing his data table for the vertical blood droplet study. Entering his measurements for blood droplets falling from different height, all of which have a 90 degree angle if incidence.

Roberto and Steven are creating a low speed blood spatter pattern  produced when the angle of incidence is 90 degrees. This is done by putting a sample of blood on the back of one hand and slapping the sample with the other hand, pushing it towards the surface.

The results of the 90 degrees low speed spatter.

Kailey, Kylie, Claire and Catie make sure they have the proper height measurement on the metric side of their tape measure before they begin to make their blood droplet samples into the angle of incidence apparatus.

Kailey drops the simulated blood from a Pasteur pipette at the height indicated by Kylie.

Two droplets done!

Three droplets done!

Francie is preparing multiple blood droplets from a fixed height.

Kylie and Kailey are working on "stringing" the blood spatter on the walls of their "cabin". The cardboard box represents a 1/8 model of the crime scene where the bodies of a male and a female were found.

Vivian, Chrissy, Katie, and Matt's model is almost complete. The strings represent the "direction" from which the blood spatter originated.  The places where the strings converge are the probable positions of the victims when they were attacked.