“Every Contact Leaves a Trace” Locard’s Principle

General Terms Lifting- press lengths of translucent tape onto the surface of the garment. Tape lifts can be examined by hand lenses or microscopes. Picking- Use forceps to lift traces of materials onto a clean sheet of paper. Can be examined by hands lenses or microscopes. Scraping- Use a clean edge of the forceps to dislodge trace materials adhered on the material to a clean sheet of paper.

Materials Old Socks 2 sheets white unlined paper Pen Hand lens

Procedure-Part A Go outside, and make observations of the 3 different areas available. Obtain a sock, record the number. Put the sock over the OUTSIDE of your shoe, and walk around in one of the 3 areas identified. Put sock in a bag, with the number written on the outside. Record your name and the area walked while wearing the sock on the “Master List”

Procedure-Part B Get into a group. Gather materials: forceps, white paper, tape, hand lens, 2 socks (different from the ones you worked on) Collect evidence from socks and fill out data table.