Forensic Sciences and Engineering: Now it's bang on! - Practical shooting exercise and gunshot residue analysis

Professor Thomas Fischer conducts a practical shooting exercise. Students on the Forensic Sciences and Engineering Master's programme can learn how gunshot traces are created. They then analyse the traces from the bullet hole, the weapon and the shooter's hands in the laboratory.

Very important during the exercise: wear safety goggles and hearing protection

After a short briefing on how to handle the alarm guns, the students are allowed to shoot a revolver and a pistol themselves - wearing safety goggles and hearing protection. The latter is also necessary, as Prof. Fischer says: "It bangs, and it bangs loudly. Your ears will ring if you don't wear hearing protection." Shots are fired at a paper target from various distances (5, 10, 15, 30 and 45 centimetres) using blank cartridges. This creates comparable images of gunshot trails. Even with the naked eye, it is possible to see how the distance between the weapon and the target influences the quantity and scattering of the traces.

The samples are analysed using a scanning electron microscope

At the test site, gunshot residue samples are taken from the shooters' hands and the barrel of the firearms. Once in the laboratory, a small sample is first cut out of the shot paper and all samples are coated with a wafer-thin layer of gold - this process is called gold sputtering. This allows the samples to be analysed using a scanning electron microscope.

Chemistry lab technician Mandy Turski explains: "The microscope shoots concentrated electron beams at the coated sample, which itself scatters electrons back. The ejected electrons then appear as an image. The darker the area of the image, the lower the density of the displayed substance." This distinction made it possible to clearly recognise the traces of lead, barium and antimony. The gunshot residue itself is caused by the combustion products of the cartridge's primer and propellant when the firearm is fired and remains in microscopic stains on the weapon, target and shooter.

Further practical exercises in the Forensic Sciences and Engineering study programme

As part of the Forensic Sciences and Engineering Master's degree course, Professor Fischer conducts further practical exercises, for example on the analysis of drugs, textiles, fire patterns or colour value reversal on infrared images. Here, students can apply their theoretical knowledge in practice and deepen their knowledge.

In addition to the Master's programme, BTU Cottbus-Senftenberg also offers the certificate programme Fire Investigation - Chemistry and Physics of Fire. This professional development programme, which is unique in Germany, lasts two semesters and concludes with a Certificate of Advanced Studies (CAS). It is primarily aimed at police fire investigators, fire experts and graduates of the Master's programme. About the programme content.