Polyolefins such as polyethylene undergo slow degradation when placed in air. Degradation occurs by reactions with atmospheric oxygen that lead to the formation of carbonyl groups (groups containing oxygen), gradual….
Prepare your testimony as an expert witness on tool marks.
Instead of working with photographs, use four different screwdrivers to prepare tool impressions. Select one screwdriver to be the crime-scene tool and prepare an impression on a piece of soft wood (like pine) to serve as crime-scene evidence. Take photographs and measurements, and prepare a cast of the tool impressions. Prepare your testimony as an expert witness on tool marks. Include measurement charts of four screwdrivers and the crime scene photographs along with casts to support your testimony. Be prepared to present evidence to the class and defend your findings.