Authors Jeanette Jolley and John Powrie

Authors Jeanette Jolley and John Powrie

Credits Associate Editor Josh Roby Assistant Editor Leslie Huber, M.A. Editorial Director Dona Herweck Rice Editor-in-Chief Sharon Coan, M.S.Ed. Editorial Manager Gisela Lee, M.A. Creative Director/ Cover Artist Lee Aucoin Illustration Manager Timothy J. Bradley Print Production Manager Don Tran Interior Layout Design/ Print Production Robin Erickson Publisher Corinne Burton, M.A.Ed. Shell Education 5301 Oceanus Drive Huntington Beach, CA 92649-1030 http://www.shelleducation.com ISBN 978-1-4258-0167-0 2008 Shell Education Made in U.S.A. The classroom teacher may reproduce copies of materials in this book for classroom use only. The reproduction of any part for an entire school or school system is strictly prohibited. No part of this publication may be transmitted, stored, or recorded in any form without written permission from the publisher. 2 #50167 Standards-Based Investigations: Forensic Science Shell Education

Table of Contents Introduction and Research Base..... 5 How to Use This Book............. 6 Correlation to Standards........... 7 What Is Forensic Science?......... 11 Using Forensic Science: Contact Traces................ 28 Fact Sheets and Lab Activities...... 30 Fact Sheet: Hair............... 30 Comparing Hairs.............. 32 Fact Sheet: Fibers.............. 34 Comparing Fibers.............. 36 Fact Sheet: Blood.............. 37 Comparing Blood Samples....... 42 Fact Sheet: Blood Splashes....... 44 Blood Splashes................ 46 Fact Sheet: DNA.............. 49 Extracting DNA............... 54 Fact Sheet: Paint Chips.......... 58 Comparing Paint Flakes......... 60 Fact Sheet: Infrared and Ultraviolet Light............. 62 Liquids in UV Light............ 64 Fact Sheet: Spectroscopes....... 65 Spectroscopy................. 67 Fact Sheet: Glass.............. 69 Comparing Glass.............. 72 Fact Sheet: Soil................ 74 Comparing Soils............... 75 Fact Sheet: Classifying Soil....... 77 Measuring Soil Particle Size...... 78 Measuring Water in Soil......... 79 Measuring Humus in Soil........ 81 Fact Sheet: Soil and Ultraviolet Light...................... 83 Comparing Soil Under UV Light.. 84 Fact Sheet: Acidity Indicators in Soil..................... 85 Fact Sheet: Soil Case Study....... 86 Measuring Soil Acidity.......... 87 Fact Sheet: Fingerprints......... 89 Fact Sheet: Three Patterns of Fingerprints................ 91 Fact Sheet: Matching Fingerprints.. 94 Fact Sheet: Fingerprinting........ 96 Taking Fingerprints............. 98 Fact Sheet: Dusting for Latent Fingerprints............... 100 Taking Latent Fingerprints...... 104 Fact Sheet: Tool and Tire Impressions............... 106 Fact Sheet: Preserving Impressions............... 107 Fact Sheet: Making a Cast...... 109 Fact Sheet: Casting Material Characteristics............. 110 Making a Cast............... 112 Fact Sheet: Footprints.......... 116 Comparing Footprints.......... 118 Evidence in Shoe Prints........ 119 Determining Events from Snow Tracks............... 122 Fact Sheet: The Characteristics of Tools................... 123 Comparing Tire Marks......... 126 Fact Sheet: Difficult Casting Situations................. 127 Shell Education #50167 Standards-Based Investigations: Forensic Science 3

Table of Contents (cont.) Fact Sheet: Two Pot Mixtures.... 128 Two Pot Casting.............. 130 Fact Sheet: Tooth Marks........ 132 Teeth Impressions in Cheese.... 135 Teeth Impressions in Apples..... 136 Comparing Dental Casts....... 137 Fact Sheet: Chromatography..... 140 Comparing Pens.............. 142 Fact Sheet: Metal Forgery....... 144 Uncovering Metal Forgery...... 146 Fact Sheet: Handwriting........ 149 Comparing Handwriting....... 152 Fact Sheet: Typewriters......... 154 Fact Sheet: Indentations........ 156 Reading Indentations.......... 158 Fact Sheet: Seat Belts.......... 160 Fact Sheet: Inertia............. 161 Collision!................... 162 Incisors Premolars Molars Canines Answer Key................... 164 References Cited and Resources... 176 4 #50167 Standards-Based Investigations: Forensic Science Shell Education

Hair Although hair cannot usually identify a single individual as fingerprints can, hair found at a crime scene can be very useful. Besides giving some indication of age, race, and sex, hairs found at a crime scene can strengthen the links between a suspect and that scene. Human hair can be classified into six groups, according to its origin: Hair from the scalp tends to have a circular cross-section, often with somewhat split ends. Beard hair often has a more triangular cross-section. Eyebrows and eyelashes also have a circular cross-section, but their ends are tapered. Underarm hair has a more oval cross-section than the other types. Pubic hair is often short, curly, and stiff, with an oval or triangular cross-section and short roots. General body hair is finer and softer than pubic hair, but is also curly and either triangular or oval in cross-section. Hair is composed mainly of the protein keratin, which is very difficult to destroy except by fire and certain chemicals. It will remain preserved in the grave longer than most of the body except for the bones. Microscopic inspection of hair can also indicate whether hair was pulled out, cut off, or just fell out naturally. cuticle Every person s hair is also unique in the trace elements it contains. These chemicals reflect the food you eat, your work and home environment, and any drugs and poisons you may have consumed as well as the shampoos and other chemicals like dyes and bleaches that you may have put on your hair. In the 1960s, when some of Napoleon s hair was obtained and analyzed more than 100 years after his death, it was found to contain many more times the normal amount of arsenic. In his day arsenic was thought to improve the complexion, but it was also a favorite method of poisoning as its taste was difficult to detect. A strand of hair consists of three layers: 1. the central core, called the medulla 2. the colored layer, called the cortex, surrounding the medulla 3. the outer layer of overlapping scales, called the cuticle cortex medulla 30 #50167 Standards-Based Investigations: Forensic Science Shell Education

Hair (cont.) Examination of all three layers can help the forensic scientist to identify the hair. The pattern of overlapping scales in the cuticle is very useful in identifying the type of animal it came from. The medulla, which can vary markedly in different people and animals, can be classified into three groups. (See the diagram to the right). In some humans the medulla may be absent, but the most common is a fragmented medulla. Humans from Asia tend to have a continuous medulla. It is usually cylindrical in shape in humans, but this is not true for many animals. For example, the medulla in cat hair is like a string of pearls. continuous interrupted fragmented Comprehension Questions 1. Write a paragraph explaining all the information that might be gained about a person whose hair was found at a crime scene. 2. What are the six parts of the human body that have hair with different characteristics? 5. What information can a forensic scientist find by inspecting the medulla of a hair sample? 6. How can inspection of the cuticle help in identifying hair? 3. Of what substance is hair made? How durable is this substance? 4. Name the three layers of a strand of hair, and describe where each is found. Shell Education #50167 Standards-Based Investigations: Forensic Science 31

Comparing Hairs Name In this activity, you will inspect a number of labeled slides of different hairs under the microscope. You will then use the labeled slides to help you identify some unknown hairs. Materials normal compound microscope labeled, prepared slides of some different hairs from different parts of the human body as well as some common animal hairs some slides of unknown hairs Procedure 1. In your science notebook, under the heading Looking at Hairs, draw the following table: Type of Hair Description Unknown 1 Unknown 2 2. Look at each hair under the microscope, then write down a description of its appearance in the right-hand column of the table. 3. Using the information you gained from examining the known hairs, try to identify the unknown hairs. Were they human or animal? If human, what part of the body? If animal, what type of animal? 32 #50167 Standards-Based Investigations: Forensic Science Shell Education

Name Comparing Hairs (cont.) Analysis 1. What differences did you notice in the hairs from different parts of the body? 2. How did the animal hairs differ from the human hairs? 3. Where do you think the unknown hairs came from? How difficult was it to identify them? 4. What features on the hairs enabled you to tell where each had come from? 5. Look at the diagrams below of the medullas of three different animals and that of a human, magnified 450 times. Try to identify where the hair found at the crime scene came from. human hair cat dog mouse crime scene hair Shell Education #50167 Standards-Based Investigations: Forensic Science 33