Forensic Science Unit Four Mrs. Pearson’s First Semester Forensic Science Forensic Science Unit Four *For those watching by recording, watch for questions on the slides throughout the presentation. Email me the answers to the questions within two days of the lesson being presented in order to receive credit for watching the recording.

Fingerprints-what do they tell us?

Bodily Fluids http://www.youtube.com/watch?v=hUQ4LtDs bRo If you find a great link you’d like to share, please send it to me! 

So what do you need to know to be successful on the assignment? The three basic patterns of fingerprints and how often does each occur The definition of a medulla and what scientists use it for What is a precipitin test and what is it used for What makes fingerprints individual and how is a match determined How are fingerprints found at a crime scene What physical evidence is most important at a crime scene and why The importance of blood stain patterns The importance of the bite marks in the Bundy case

Lets begin with how to get a fingerprint at home and in the world http://www.youtube.com/watch?v=4bBCHByh pF4 http://www.youtube.com/watch?v=DlVhSCu1 sSE&feature=related

Fingerprints Good source of evidence Remain the same your entire life Unique to each person Easy to catalogue in a system Can be left on nearly anything **Those watching by recording, include in your email three reasons why fingerprints are a good source of evidence.

History of Fingerprinting Can be traced back to India, Babylonia, Nova Scotia, and China The first prints taken in the US were in the 19th century Were studied using magnifying glass The case of the People vs. Jennings in 1911 established fingerprinting as a legal method of identifying people Fingerprints still solve 10 times more cases that DNA

Latent Prints Can be either negative or positive Can be studied in two ways Oblique lighting- shining the light at an angle to reflect the print Powder copy Various types of powder are used

Collecting a Print Latent print Power is applied Chemical is applied Brushed, blown, or poured on Different types of brushes are used based on the location of the print Chemical is applied Makes prints visible on absorbent surfaces Can reveal even invisible prints **Those watching by recording, include in your email what type of surface chemicals are used on to reveal fingerprints.

Documenting a Fingerprint Proper steps Photographed with ruler Taken to lab, if possible Item is not wrapped, but is placed in secure box to avoid smudging the print If item is too large or stationary, the print is lifted using tape and place on a card to transport back to the lab. Determine a pattern and study individual characteristics (minutiae) Must have 8-16 points of comparison to be considered a match

Fingerprint Patterns 3 basic patterns Arches Tented- ridges flow from one side to the other but are interrupted by a ridge Plain- ridges flow from one side to the other without interruption

Loops – a ridge that goes out the same side it entered Must have only one delta Whorls- a ridge that contains 2 or more deltas and recurves back on itself Plain Central pocket Double loop Accidental

Labs Fingerprints Lost Mine What should you do before completing the labs? Read the lessons When you submit the answers, what are you going to be sure your paper contains? Both the questions and answers Complete sentences Proper grammar and spelling

Explore a Career Jennifer Hannaford Teachers' Domain, Jennifer Hannaford, published September 18, 2007, retrieved on September 12, 2010, http://www.teachersdomain.org/resource/city07.sci.engin .systems.hannaford/

That’s a Wrap! New means of gathering fingerprints are being developed Fingerprints are unique to each person Whorls, loops, and arches Latent fingerprints can be recovered using powder or lighting Documenting of fingerprints follows specific guidelines When submitting work, remember spell and grammar check, include the questions with the answers and name your file as described in the course announcements!

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