This activity (on page 2 of the PDF under SciGirls Activity: Forensics) is a full inquiry investigation into how hairs from a crime scene are matched to suspects. Learners each take a single hair from their own head, then put it directly into the beam of a laser pointer. This projects the unique pattern of each hair onto a piece of paper to be traced, measured, identified and compared with the others. Learners can conclude this activity by setting up a mystery exercise with prepared samples of hair already in frames. Relates to linked video, DragonflyTV: Forensics.