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How is Chemistry used in Forensic Science?

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Avery Kampfmueller

on 21 February 2013

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Transcript of How is Chemistry used in Forensic Science?

By: Avery Kampfmueller What is Forensic Science? Forensic science (often shortened to forensics) is the application of a broad spectrum of sciences and technologies to investigate and establish facts of interest in relation to criminal or civil law What does it take to be a Forensic Scientist? According to the American Academy of Forensic Science, a forensic scientist must have, at minimum, a bachelor's degree in science. Common majors include chemistry, physics, forensic science or biology. Students must take at least 24 semester credits of chemistry or biology, and math is required. How does Chemistry relate to Forensic Science? :: Slide 1 Blood Analysis: Aside from being used for identification of suspects, the contents of blood on a crime scene can be evaluated to reveal the presence of substances. For this evaluation, a chemist will perform a chromatography test, which uses intense heat to separate the blood into different contents. Afterward, a chemist determines the level of substances such as alcohol or medication that would affect the suspect´s actions and motivations during a given crime. How does Chemistry relate to Forensic Science? :: Slide 2 DNA Forensics in Criminal Cases: DNA forensics is used in criminal cases to match the DNA of an individual to that of body cells left at a crime scene, such as skin cells, hair, and blood. The FBI most commonly uses STR-analysis for its cases. With STR-analysis, chemists take DNA samples from areas at the crime scene. These are then compared with the DNA profiles of individuals booked in an expansive database called CODIS to identify suspects. How does Chemistry relate to Forensic Science? :: Slide 3 Firearms Analysis: Chemistry is often used in crimes involving firearms in order to identify information from recovered bullets and residue. For example, a forensic scientist will examine a suspect´s hands and clothes with infrared lights to look for gunpowder residue. If this residue matches that of the bullet found in the victim, there is evidence that the suspect recently fired the same type of firearm responsible for harming the victim. If no gunpowder residue is found on a suspect, a chemical analysis of the bullet can still reveal information such as the type of firearm used and how long ago the bullet was fired. Cases where Forensic Science was used to determine the outcome O.J. Simpson Although 99% of the world believes OJ Simpson to be guilty of murdering his ex-wife and her friend, one question surrounding the case remains a complete mystery: did two police plant DNA evidence at the scene to try and create a slam-dunk case? Detective Furman, who was ousted as a violent racist during the trials, was accused of planting OJ’s glove at the scene. Additionally, it was proven that Simpson’s blood sample was brought to the crime scene by a police evidence technician, and it was later discovered that the tube of blood only contained 6cc of blood when 8cc had been extracted. Simpson’s blood at the crime scene reflected DNA that had been mixed with EDTA, a substance added to blood taken for DNA testing. Furman pleased no contest to charges against his person regarding this OJ ‘conspiracy’ and is now a convicted felon. Dr. Schneeberger A South African doctor who rapee two women, one of which was a family member, used his knowledge of forensics to avoid conviction for almost ten years. Dr. Schneeberger, trained to help and heal his patients, drugged and raped one of them instead. It didn’t help that Schneeberger foiled the DNA test by inserting a tube of someone else’s blood inside of his arm, making sure that the technician was drawing blood from the exact spot in which he had placed it. When the samples didn’t match up, her case was dismissed. Suspicions were raised again, however, when Schneeberger’s own stepdaughter reported that he had raped her multiple times in their family’s home. This time, DNA was taken from Schneeberger’s mouth, blood, and hair. He was convicted but only sentenced to six years in prison. CSI Chief Convicted of Planting DNA Evidence A person of authority and power, CSI director David Kofoed was responsible for carefully collecting DNA evidence which would convince multiple juries beyond a reasonable doubt. With a task as important as that, how could one be so careless as to accidentally contaminate the property of innocent people with ‘evidence’ which would point to their guilt? That’s exactly what Kofoed claimed happened when he planted blood samples in the car of a murder victim’s relative; the use of a contaminated testing kit was likely the reason that Kofoed had haphazardly placed blood in an innocent person’s vehicle, or so his defense claimed. The jury disagreed, and Kofoed was convicted of tampering with evidence. The two victims, a couple who had been shot down, had DNA matching blood found in their nephew’s car. However, this was the only evidence attaching their nephew to the crime and contradicted the rest of the details surrounding the case. Although Kofoed was successfully convicted, the prosecutor’s statement to the media was less than reassuring
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