Practice Assignment 01
Forensic examination of hairs
The two standard procedures listed can be used directly for this practice assignment. A sealed bag containing a hair sample from a single individual should be available for each student. These should be labelled with a number only. The bags could include examples of animal and human hairs, with a variety from blond/dark/red/straight/curly hair types. There should be several samples from each source so that the students can attempt to match up samples.
Students could bring in hairs from their pets to contribute to the variety. Wool, cotton and synthetic fibres could also be available for comparison.
The actual source of each sample should be made known only after the students have compared notes and reached some conclusions about which hairs are from the same person or animal.
Health and safety note
Animal hairs should be avoided if there are students present who might suffer an allergic reaction.
Apparatus and reagents
- Standard Procedures:
- SP 0001:2005 Methods for setting up and adjusting a light microscope
- SP 0002-1:2005 Methods of preparing slides for microscopy – Part 1: Mounting a hair or other fibre
- microscope with two or more objectives
- pre-prepared specimen slide (e.g. microdot - Philip Harris catalogue item C5A76090)
- light source (lamp or good daylight)
- specimens (hairs or other thin fibres)
- microscope slide and cover slip
- disposable dropper
- forceps
- mounted needle
- mountant e.g. DPX
Caution: contains xylene (dimethylbenzene) – harmful, irritant. Available from BDH Chemicals (VWR International, Poole, BH15 1TD 01202 669700 www.vwr.com) .