Introduction to Forensics Section 1

Section 1: Introduction to Forensic SciencePreview• Bellringer• Key Ideas • What Is Forensic Science?• Tools of Forensic Science• Summary

Introduction to Forensics Section 1

Bellringer

What do you think a forensic scientist does? List as many things as you can think of that you have seen forensic scientists do on television.

Introduction to Forensics Section 1

Key Ideas

• What are the two major duties of forensic scientists?

• What are five basic types of tools used by forensic scientists?

Introduction to Forensics Section 1

What Is Forensic Science?

• Forensic science is the use of science to investigate legal matters.

• Forensic science can be used in any type of legal matter, from crimes to contracts.

• The two major duties of a forensic scientist are analyzing evidence and testifying in court.

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What Is Forensic Science, continued

Analyze Evidence• Any time two people come into contact, evidence is

exchanged.

• This idea is known as the Locard exchange principle.

• It means that when a crime is committed, some kind of evidence will always be produced.

Introduction to Forensics Section 1

What Is Forensic Science, continued

Analyze Evidence• In forensic science, the word identity has two meanings.

– The first meaning involves the question “What is it?”

– The second meaning involves the question “Whose is it?”

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What Is Forensic Science, continued

Analyze Evidence• Forensic scientists analyze evidence in order to

determine what the evidence is and to whom it belonged.

– For example, if a red stain is found at a crime scene, the first step is to determine what the stain is.

– If the stain is blood, the next step is to determine whose blood it is.

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What Is Forensic Science, continued

Testify In Court• The second major role of a forensic scientist is to provide

expert testimony in court.

• An expert witness is someone who has education, training, or significant experience in a particular subject.

• Expert witnesses are allowed to give their opinions in court.

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What Is Forensic Science, continuedMore Than Crime Scenes• Forensic scientists do more than investigate crime

scene. In addition, forensic scientists– identify victims of accidents and disasters– investigate fires for clues about arson– verify documents and products– detect forged signatures, money, passports, and

paintings– identify fake goods– trace the spread of computer viruses– locate hackers and investigate internet fraud

Introduction to Forensics Section 1

Tools of Forensic Science

• To become a forensic scientist, a person must have a bachelor’s degree in forensic science, criminalistics, chemistry, biology, biochemistry, or physics.

• Forensic scientists also must have good communications skills.

• Five basic tools used by forensic scientists are chemicals, microscopes, chromatographs, spectrometers, and computers.

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Tools of Forensic Science, continued

Crime Scene Chemistry• There are many chemicals used by forensic scientists.

• Some chemicals reveal bloodstains.

• Other chemicals detect fingerprints.

• Still other chemicals can detect gunshot residue.

• Forensic scientists also use chemistry to analyze drugs, alcohol, poisons, fire accelerants, and explosives.

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Tools of Forensic Science, continuedLooking at Details• One of the most important tools in forensic science is the microscope.

• Handheld lenses can be used at crime scenes.

• Light microscopes are used to examine evidence and to separate evidence for further analysis.

• Scanning electron microscopes are used to take a picture of very small objects.

• Comparison microscopes are used to compare two small objects, such as bullets, side by side.

Introduction to Forensics Section 1

Visual Concept: Types of Microscopes

Click the button below to watch the Visual Concept.

Introduction to Forensics Section 1

Compound Light Microscope

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Tools of Forensic Science, continued

Identifying Substances• Two basic tools are often used to identify an unknown

substance.– A chromatograph separates chemicals based on their

physical properties, such as boiling point or molecular size.

– A spectrometer records how a substance interacts with wavelengths of electromagnetic radiation.

• Data from these tools can be used alone or combined to provide more information.

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Tools of Forensic Science, continued

Organizing Information• Without computers, much of the work that forensic

scientists do would be difficult and time consuming.

– Computers link to microscopes, chromatographs, and spectrometers to display results.

– Databases store information that forensic scientists can search easily.

Introduction to Forensics Section 1

Summary

• The two major duties of forensic scientists are analyzing evidence and testifying in court.

• Five basic types of tools used by forensic scientists are chemicals, microscopes, chromatographs, spectrometers, and computers.