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Do Now: Update your tracker!

Objectives: . Students will be able to describe, compare, and perform fingerprint detection techniques. . Do Now: Update your tracker! 1.Explain the history of the fingerprint system so far. ( bertillonage system to galton system) 2. How is the 12 point system used in forensic science?

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Do Now: Update your tracker!

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  1. Objectives: Students will be able to describe, compare, and perform fingerprint detection techniques. Do Now: Update your tracker! 1.Explain the history of the fingerprint system so far. (bertillonage system to galton system) 2. How is the 12 point system used in forensic science? 3. By looking at fingerprints patterns (whorls, loops, arches), would that be considered class or individual evidence? Why?

  2. Announcements • Quiz on Tuesday • Bring gloves for Monday

  3. Review Fingerprints Patterns Minutiae History

  4. Henry Classification System Simplified Galton’s system Allowed all sets of fingerprints to be divided into 1,024 groups Ten card Submit fingerprints, millions of sets are weeded out only a few dozen will be left to compare

  5. How does it work? Identify the presence of whorls on each finger For each finger that has a whorl, you add the number If no whorl is present, then you add zero Example….. Calculate your Henry Classification number.

  6. Latent, Plastic, and Patent • Patent print- visible prints left by a finger that has touched colored material such as blood or paint • Plastic print- (a mold) indents left in clay, wax, etc. • Latent print- invisible until it is chemically developed

  7. Fingerprint detection Techniques Powder Testing –dusting latent print with fine powder, lift it with tape Iodine- attach to oils from fingers Ninhydrin (will stain clothes and skin)- reacts with amino acids (proteins) Silver nitrate- reacts with salt

  8. Edit! • Part II- Silver Nitrate • 1. size of a notecard… • Half the size of a sticky note • Also cut in a way that you can easily identify 4.5 Remove paper with forceps

  9. Pre-lab Questions • 1. What is the difference between latent, plastic and patent prints? • 2. Why do you need to develop latent prints? • 3. Could a print be considered both latent and plastic?

  10. Objective Check! • Students will be able to describe, compare, and perform fingerprint detection techniques.

  11. Exit Ticket • 1. Visible prints left by a finger that has touched colored material such as blood or paint is called A. Latent B. Patent C. Plastic D. Paint • 2. The chemicals used to develop latent prints reacts with the _______ left by your fingers. (may be more than one answer) • 3. Describe the history of the fingerprint system. (bertillonage, Galton, Henry)

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