Lighting Up a Crime Scene: Fluorescence in Forensics

Jackie Smith, Science, William A. Hough High

Curriculum Unit (PDF)


This unit examines the importance of fluorescence to forensic science for latent evidence detection and analysis. It starts with a review of the dual theory of light and the electromagnetic spectrum. The use of visible light for the detection of evidence is discussed as well as its’ use in the analysis of substances. Microscopy is explored through a lab activity. Light emissions are looked at with a focus on photoluminescence and chemiluminescence. These processes are studied before turning to their forensic applications. The unit presents several hands-on activities exploring fluorescence including a fingerprinting lab that uses ninhydrin and silver nitrate development as well as fluorescent powders and ultraviolet light to visualize latent evidence. A Luminol lab is presented where students are able to work with simulated blood, Luminol and bleach to discover the role of fluorescence in blood detection at crime scenes. A Color Lab is suggested for students to experiment with different substances they are likely to find at a crime scene by using different wavelengths of light, color filters and goggles to optimize the appearance of latent evidence.