DIY Science Illustrated Guide to Home Forensic Science Experiments All Lab, No Lecture First Edition Robert Bruce Thompson and Barbara Fritchman Thompson BEIJING • CAMBRIDGE • FARNHAM • KÖLN • SEBASTOPOL • TOKYO Illustrated Guide to Home Forensic Science Experiments All Lab, No Lecture by Robert Bruce Thompson and Barbara Fritchman Thompson Copyright © 2012 Robert Bruce Thompson and Barbara Fritchman Thompson. All rights reserved. Printed in Canada. Published by O’Reilly Media, Inc., 1005 Gravenstein Highway North, Sebastopol, CA 95472. O’Reilly Media books may be purchased for educational, business, or sales promotional use. Online editions are also available for most titles (my.safaribooksonline.com). For more information, contact our corporate/institutional sales department: 800-998-9938 or [email protected]. Print History Editor: Brian Jepson July 2012 Production Editor: Melanie Yarbrough First Edition Copy Editor: Bob Russell, Octal Publishing, Inc. Proofreader: Linley Dolby Indexer: Bob Pfahler Cover Designer: Mark Paglietti Cover Photograph: Robert Bruce Thompson Interior Designer: Ron Bilodeau Illustrator: Rebecca Demarest The O’Reilly logo is a registered trademark of O’Reilly Media, Inc. The DIY Science series designa- tions, Illustrated Guide to Home Forensic Science Experiments: All Lab, No Lecture, and related trade dress are trademarks of O’Reilly Media, Inc. The trademarks of third parties used in this work are the property of their respective owners. Important Message to Our Readers: Your safety is your own responsibility, including proper use of equipment and safety gear, and determining whether you have adequate skill and experience. Chemicals, electricity, and other resources used for these projects are dangerous unless used properly and with adequate precautions, including safety gear. Some illustrative photos do not depict safety precautions or equipment, in order to show the project steps more clearly. These projects are not intended for use by children. Use of the instructions and suggestions in Illustrated Guide to Home Forensic Science Experi- ments: All Lab, No Lecture is at your own risk. O’Reilly Media, Inc., and the authors disclaim all responsibility for any resulting damage, injury, or expense. It is your responsibility to make sure that your activities comply with applicable laws, including copyright. ISBN: 978-1-449-33451-2 [TI] To Edmond Locard (1877 - 1966), often called the French Sherlock Holmes, who, as a professor of forensic medicine and criminology at the University of Lyons, in 1910 established the world’s first police crime laboratory. Locard’s lab occupied two attic rooms staffed by two assistants provided grudgingly by the Lyons police department, and was initially less well equipped than the home forensics lab we used in writing this book. Despite these limited resources, Locard’s results soon convinced police departments worldwide, including Scotland Yard and the FBI, to found their own crime labs. Locard was the first to state the fundamental principle of forensic science, now known as Locard’s Exchange Principle: “Wherever he steps, whatever he touches, whatever he leaves, even unconsciously, will serve as a silent witness against him. Not only his fingerprints or his footprints, but his hair, the fibers from his clothes, the glass he breaks, the tool mark he leaves, the paint he scratches, the blood or semen he deposits or collects. All of these and more bear mute witness against him. This is evidence that does not forget. It is not confused by the excitement of the moment. It is not absent because human witnesses are. It is factual evidence. Physical evidence cannot be wrong, it cannot perjure itself, it cannot be wholly absent. Only human failure to find it, study and understand it, can diminish its value.” Contents Preface ...........................................................................................................................................xiii 1 Laboratory Safety ......................................................................................................... 1 2 Equipping Your Forensics Laboratory .........................................................................5 Optical Equipment ................................................................................................................5 Laboratory Equipment........................................................................................................ 13 Chemicals and Reagents .................................................................................................... 19 Specimens ...........................................................................................................................26 Group I Soil Analysis .................................................................................................................31 Lab I-1 Gather and Prepare Soil Samples ............................................................................ 35 Equipment and Materials ...................................................................................................35 Background .........................................................................................................................36 Procedure I-1-1: Gather Soil Specimens ............................................................................37 Procedure I-1-2: Dry Soil Specimens .................................................................................38 Review Questions ............................................................................................................... 40 Lab I-2 Examine the Physical Characteristics of Soil ......................................................... 43 Equipment and Materials ...................................................................................................43 Background .........................................................................................................................44 Procedure I-2-1: Observe and Categorize Soil Color ........................................................44 Procedure I-2-2: Determine Soil Density ..........................................................................46 Procedure I-2-3: Determine Soil Settling Time .................................................................48 Procedure I-2-4: Determine Soil Particle Size Distribution .............................................49 Review Questions ................................................................................................................52 Lab I-3 Examine the Microscopic Characteristics of Soil .................................................. 55 Equipment and Materials ...................................................................................................55 Background .........................................................................................................................56 Procedure I-3-1: Examine Soil Specimens under Magnification .....................................57 Review Questions ................................................................................................................58 Lab I-4 Assay Phosphate Concentrations in Soil Specimens .............................................61 Equipment and Materials ................................................................................................... 61 Background .........................................................................................................................62 Procedure I-4-1: Extract Soil Specimens ...........................................................................63 Procedure I-4-2: Assay Soil Phosphate Concentrations .................................................64 Review Questions ................................................................................................................65 Contents v Lab I-5 Examine the Spectroscopic Characteristics of Soil ...............................................67 Equipment and Materials ...................................................................................................67 Background .........................................................................................................................68 Procedure I-5-1: Extract Ion Species from Soil Specimens .............................................69 Procedure I-5-2: Test Soil Specimen Extracts with the Spectrometer ...........................69 Procedure I-5-3: Identify Ions Present in Exemplar .........................................................72 Review Questions ................................................................................................................73 Group II Hair and Fiber Analysis ...............................................................................................75 Lab II-1 Gathering Hair Specimens .........................................................................................79 Equipment and Materials ...................................................................................................79 Background ........................................................................................................................ 80 Procedure II-1-1: Obtain Hair Specimens with Forceps .................................................... 81 Procedure II-1-2: Obtain Hair Specimens with Lift Tape ..................................................82 Review Questions ................................................................................................................83