Forensic Short Answer Questions

What is density and how does heat affect the density of gases and liquids

Density is equivalent to the mass per unit volunme of a substance. As the temperature rises, the object is more dense.

What is a standard/reference sample and why is it important to the criminalist?

It is an unknown sample that can be used to compare to evidence at the crime scene. It can be used to compare evidence at a crime-scene to evidence from a suspect or victim

Define intensive and name 2 intensive properties of matter

Intensive property is not dependent on the size of an object. Density and volume

What are IAFIS and CODIS? Describe the purpose of each

1. Integrated Automated Fingerprint Identification System. A national fingerprint and history database maintained by the FBI. 2. Combined DNA Index System, enables federal state, and local labs to electronically exchange and compare DNA profiles

List three specialized skills that a criminalist can apply during crime-scene reconstruction

1. blood splatter analysis 2. determining the direction of impact of projectiles penetrating glass objects. 3. locating gunshot residue

List six type of physical evidence derived from human of other animal sources that commonly are found at crime scenes

1. documents 2. drugs 3. explosives 4. fingerprints 5. fibers 6. firearms and ammunition

List 4 situations in which a warrantless search may be justified

1. emergency 2. so as not to loose evidence 3. if they are going to make an arrest 4. with consent from that person

Descirbe in some detail the two noncriminal homicides

1. justifiable homicide - when a police officer kills a felon 2. excusable homicide - when it is an accident, like an allergic reaction

Describe the three criminal homicides

1. murder in the first degree: premeditated, afterthought. 2. second degree: not premeditated, afterthought 3. 3rd degree: accident, no intention of killing someone

Compare and contrast misdemeanors and fealonies. Give an example of each

A misdemeanor is rape and sexual battery. A fealony or white-collar crime means that there was no violence, for exapmple robbery

What is a rough sketch and what information must it accurately reflect?

A rough sketch is a draft of the crime scene and all the measurements. It must depict the dimension of the scene and all physical evidence and where it was found.

Describe the two steps in the process of comparison. What question does each step attempt to answer?

First properties from the suspect and standard/reference specimen are chosen for comparison. Then, when the examination is completed, a conclusion of the origin of the specimen is drawn. It attempts to answer if two specimen have a common origin.

How can soil evidence be valuable even if the site of the crime has not been ascertained?

It can provide associative evidence that can link a suspect or object to the crime scene.

What is the main objective in collecting and packaging physical evidence?

So that no change takes place between the time the evidence is picked up from the crime scene, to the time it reaches the lab

Why should blood stained evidence not be stored in airtight containers? What is the best way to store such evidence?

The accumulation of moisture can encourage the growth of mold, which can damage the blood evidence. The best way to store it is in manila folders, paper bags, or packaging paper

Define the terms refraction and refractive index

The bending of a light wave as it passes from one object to another The ratio of the speed of light

What is the best way to maintain the integrity of evidence that is collected and submitted to the crime laboratory?

The best way is to leave it unaltered and the way it was found

What is the greatest weakness of class evidence? List two factors that contribute to this weakness.

The inability of the examiner to assign exact probability values to the comparison of most class physical evidence. 1. very few statistical data are available. 2. a society that is dependent on mass-produced products

Define the product rule and explain how it can be used to determine whether two blood samples come from the same source

The product rule is used to obtain an overall frequency of occurrence for a genetic profile. If you use a series of blood factors that occur independently, you can use the product rule to calculate the overall frequency of occurrence of the blood in a population

What is the 3R rule and how is it applied to the analysis of glass fractures?

When radial cracks form a right angle on the reverse side of the force. It enables the examiner to determine the side of the window that was broken.

Define the terms physical and chemical property

defines the behavior of a substance without altering the compostion chemical property describes the behavior when combined with another substance