1. Hair Analysis Forensic Science Lawndale

2. Hair Analysis: Hairs are one example of trace evidence which can be examined under the microscope. Unfortunately, hair is not the best type of physical evidence for establishing identity.

3. Hair Analysis (Cont) It is impossible to show with any certainty that two hairs came from the same person. Hair can be used to rule out certain suspects or scenarios. It can be used to support other physical evidence if it is consistent with the rest of the evidence

4. Hairs can be grouped in 2 ways: Racial origin Body location Hair examiners can often conclusively eliminate a person as a source of a hair, but rarely can an examiner absolutely associate a hair sample to a given individual.

5. How is hair analyzed? Two ways: Visual Observation- simplest method of identification done with the naked eye, indicate color, length, and amount of curl. Microscopic Examination-Reveals characteristics of its physical structure.

6. Quiz- Get out a piece of binder paper 1. T/F- Hair is evidence that can always link a suspect to a crime scene. 2. Identify 2 ways scientists can examine hair. 3. Identify the two ways hairs can be grouped. 4. Describe one way scientists can use hair as evidence. 5. The three principle parts of hairs are -

7. Structure of Hair Hair is composed of three principle parts: (Similar to graphite pencil) Medulla – Cortex - Cuticle –

8. Medulla Central Core, which may be absent Appears dark when the exhibit is mounted in a liquid (via a microscope) –May not be visible May vary in thickness and continuity (one continuous structure or broken in pieces).

9. Cortex Middle layer of the hair shaft Provides strength Makes up most of the mass of hair Contains microscopic features such as: pigment, color, size, and distribution.

10. Cuticle Outer coating composed of overlapping scales Most important detail in determining from which individual a human hair may have come.

11. Cuticle Scales of the cuticle can be different shapes and textures Thickness may vary as well

12. Biology of Hair Hair is an outgrowth of the skin and is produced from a structure called the hair follicle. Hair is made of the same thing as your fingernails called keratin

13. Hair Color Hair color is the result of 2 main pigments – chemical compounds which reflect certain wavelengths of visual light. Eumelanin – gives color to brown or black hair Pheomelanin – produces the color in blonde or red hair.

14. Get out a sheet of binder paper

15. Hair Shape and texture Shape – round, crescent or oval cross- section Texture – curly, wavy, straight, kinky Both are influenced heavily by genes!!!! However, nutritional status and intentional alteration (heat, curling, coloring) can affect the physical appearance of hair.

16. Good Vs Damaged Hair