Scientific Method Applied to Forensic Science - Essay Example

Scientific Method Applied to Forensic Science Introduction to Scientific Method Scientific method is a group of techniques designed for studying phenomena and gathering evidence and new knowledge in addition to using old information while combining both. The key point being acquiring observable, empirical and calculated evidence and using cognitive abilities of reasoning under certain principles. Every field of inquiry uses different procedures of scientific method. Scientific inquiry uses certain methods that differ from other methods of gathering knowledge. Scientific method usually involves studying natural phenomena and forming hypotheses to explain them. Experiments are then performed to measure the accuracy of these hypotheses and they are repeated several times in order to determine whether or not the phenomena behaves according to the predictions laid out by the hypotheses i.e. whether the tests are predictable (Wudka 1998). Some domains of inquiry tend to come under certain theories which permit the structuring of specific hypotheses. Almost all fields of inquiry share the common ideal that the manner of gathering data and acquiring new knowledge must be unbiased and objective. This leads to accurate observation, data gathering and interpretation of results. Scientific method also requires that the data is documented, shared and accessed in order for other researchers and scientists to conduct their own experiments independently and reproduce the results. This enables the statistical measurement of data and verify their reliability. Forensic Science Forensic science is a scientific method of collecting and scrutinizing evidence. It is a science that is applied to legal issues. It involves the testing of different parameters and associated references to the background information about the subject in question in order to arrive at a conclusion (Ellen 2005 p.3). Forensic scientists are specialized professionals who involve themselves in accident or crime scene investigation. They use their skills by observing, recognizing, identifying and individualizing the physical evidence available at the scene, then go about attempting to reconstruct the sequence of events that took place so that the police, lawyers and the courts can fully unravel in detail the crime or accident. Observation and Description in Forensics As in other fields of scientific study, forensic scientists rely greatly on scientific method. The initial first step is the observation and collection of information and data most of which is physical. Forensic scientists generally search for data at the scene or in the laboratory. This data includes physical evidence that is to be recognized as being crucial to the investigation, protected from the elements to avoid contamination and collected. Crimes are solved using pathological examinations of crime scene data such as fingerprints, footprints, palm prints, blood stains, soil, bodily fluids, plant and animal matter and hair samples. Apart from this handwriting and typed samples, including ink and paper are also studied as are impressions and questionable documents. Insects present at the scene, maybe collected and in a lab examined by a forensic entomologist. Where weapons are involved, bullet remnants, direction and range of the shot and other ballistics are studied to determine the origins of the shooting. In addition, voice identification techniques are also used to ascertain the criminal's identity. Impression evidence is also vital and can come in two-dimensional or three-dimensional forms such as shoeprints (Genge 2002 p.58). All evidence is carefully cordoned off from possible contamination, collected and placed in plastic bags or boxes, labeled with time, date and location and signed by the crime scene personnel. These and other items of physical evidence are investigated to determine that a crime has occurred and also to ascertain the criminal's Modus Operandi and establish a connection between the suspect and the victim. The other goal is to place the persons, both victim and perpetrator at the scene of the crime and support or disprove eyewitness statements and offer law enforcement investigative leads. Formulation of a hypothesis Once all the data is gathered, it is subjected to conjecture, where the physical evidence is tested and scientifically analyzed. The scientific method in forensic science involves correlating observations gathered from a scene and from experiments to build a hypothesis and test it using other methods and specifically designed experiments (Ellen 2005 p.1). The hypothesis may be formulated with regards to the identity of the physical evidence and how it ended up at the spot where it was discovered. This step is followed by testing the hypothesis. This might result in some minor or major modifications of the original hypothesis. If this newly revised hypothesis can survive further testing by a variety of other means and forensic scientists can justify and explain the observable data, then the hypothesis turns into a theory. The theory is the final outcome of the forensic investigative process and it is presented to explain precisely the nature of the crime and what happened during it. With this, a body of knowledge is developed and used to offer addition support for the investigative process. One of the two issues that a forensic scientist must resolve is identification (Fisher 2006 p.5). The other is individualization. Identification is answering the question "what is it" In some cases this involves in depth analytical work. For example if a piece of tape with some residue on the adhesive is found at the scene of a crime, the identity of the residue must be verified, whether it be salt, drugs or simply dirt. Under the microscope if the grains appear to be white cubes, a hypothesis is put forth that it is salt. To test this hypothesis, a simple chemical test to discover the presence of sodium and chloride is performed. If the test turns out positive, it will indicate that the grains are salt and therefore the residue on the tape is ascertained. But suppose the forensic scientist is asked to identify the brand of the salt, in other words individualize the salt. This poses a challenge because all brands of salts consists of the same basic elements, sodium and chloride. The differences between the brands depend on the impurities that are not the basic elements of the salt but other minerals and trace elements. The amount of water between different brands of salts can set them apart. The identification of the impurities and trace elements require more in depth analysis and sensitive tests. The examination of physical evidence is frequently the decisive aspect in determining the guilt or innocence of an individual (Nickell 1998 p.15). It also can be a material aid in pinpointing the location of the criminal. Use Of The Hypothesis To Predict Other Phenomena The key point in the scientific method is the predictive ability of a hypothesis or theory. This is the capacity to extract more from the theory than is put in. The importance of multiple testing and experiments is vital to the strength of the theory since any new observation may conflict with the established hypothesis and thereby disprove it. Sometimes hypothesis can be used to predict the occurrence of another phenomena or predict the results of new observations. For example, one initial hypothesis maintained that hair sample including color and condition was best preserved in water. But new testing techniques revealed that water was in fact a bad preservative for hair since there was a degeneration and breakdown of the overall condition of the follicle including the color turning lighter shades. The effect of natural elements on hair also led to the breakdown of DNA, which would prove costly in a criminal investigation. Debunking an old hypothesis is not unusual and may give weight to the adage that a theory can never be proved but only disproved. A good forensics expert will investigate any crime or accident in a logical scientific manner. He will continually test the current hypothesis against fresh evidence if it arises. He may modify or reject the old hypothesis if warranted by the new evidence. Ultimately a conclusion will be reached. The testing of a hypothesis may result in the confirmation of the hypothesis or its falsification. Scientific method requires that a hypothesis should be modified or dismissed if its outcomes or predictions are constantly at odds with experimental tests. Any hypothesis however seemingly compelling, must correlate with experimental results if the theory is to be admitted into court. For example, in a crime scene involving a gunshot wound, the forensic scientist may reach a theory that the bullet might have been fired at close range to the victim. The forensic pathologist may be able to trace the bullet's path through the body and try to recover the bullet if still present, and use it for comparative testing (Fisher p.78). One of the most common outcomes of a forensic investigation in gunshot cases is the distance of the weapon from the body. The nearer the victim is, the greater the likelihood that two types of gun shot wounds will occur. The first type is called stippling wounds and are indicated by the presence of punctuate abrasions on the region of the skin around the gunshot wound. Stippling is caused by unburned or still burning gunpowder traveling at a great speed as it is propelled from the gun barrel immediately behind the bullet. Closer the gun, the greater the residue from the gunpowder and the more marked the stippling. The other type of wound can enable the forensic pathologist to estimate an approximate distance the body was from the weapon. This is done by considering a ballistics fact. When the bullet is fired, the gunpowder ignites due to a chemical reaction producing expanding gases that travel behind the bullet. These gases may dissipate in the air but may also enter the wound if the body is close, causing further burn injuries to the skin and flesh. The forensic pathologist can thus using the scientific method of observation, determine distance the gun was fired from. Normally at a crime scene when a murder has taken place, blood is found at the scene. The blood may be in a pool, spray or droplets. By examining bloodstain patterns, forensic scientists can mimic the fall of blood and development of pattern in the lab thereby determining the position or direction the victim was in when the perpetrator committed the crime. Different arm actions of an attacking criminal holding a knife would produce different blood patterns. Thus the forensic scientist can fairly accurately determine the probable actions of the criminal by testing the hypothesis to predict other phenomena. Performance Of Experimental Tests In the performance of experimental tests, such as on DNA samples, numerous laboratory principle must be adhered to in order to reach accurate results (Butler 2005 p.391). These include validation, proficiency testing and laboratory accreditation. Validation is the process of showing that laboratory procedures are accurate, reliable and repeatable among the scientists of the lab. The process also needs to be robust which means that an experiment will lead to successful results a greater percentage of the time than otherwise. A reliable method offers accurate results and correctly mirrors the sample under testing. A reproducible method refers to the generation of the same or similar results upon testing the sample more than once. A proficiency test is an appraisal of a lab's performance in performing experiments. These tests are conducted periodically and their purpose is to evaluate the skills of the lab personnel for their ability to produce results that are in accordance with the lab's standard testing procedures. These proficiency tests may be conducted by an external organization or internally. If conducted by an external source, the test may be undertaken without the knowledge of the lab personnel. Tests conducted in this manner can be the most effective way of judging a lab's abilities. Involvement in these tests is an important part of gaining quality assurance standards. Laboratory accreditation assesses the whole operation of the lab. The examination maybe performed by the lab management or an external body in order to verify whether or not the lab follows operating protocols. Equipment and instruments used for DNA forensics are also analyzed for accuracy. Conclusion Forensics is intricately associated with scientific method. It is a process of human inquiry, observation, hypothesis formation and testing that pervades all forms of investigation. By using strict and correct scientific methods in forensics, the danger of experimental bias and possibilities of erroneous results from experimentation and testing can be prevented from occurring. The adherence to scientific method ensures that the data collected is treated objectively and subjected to scientific analysis in order to be presented as reliable evidence in a court of law. This allows the judicial process to be carried out in confidence, the law to take its course and perpetrators brought to justice or an incident or accident to be fully explained. References Ellen, David (2005) Scientific Examination of Documents: Methods and Techniques, Third Edition (International Forensic Scientific & Investigation Series). CRC. P.3 Fisher, Barry. Fisher, David. Kolowski, Jason. (2006) Forensics Demystified. McGraw-Hill Professional. P.5 Nickell, Joe. Fischer, John F (1998). Crime Science: Methods of Forensic Detection. University Press of Kentucky. P.15 Butler, John M. (2005) Forensic DNA Typing, Second Edition: Biology, Technology, and Genetics of STR Markers. Academic Press. P.391 Rankin, Stephanie (2007). Forensic Science Central. Available from Genge, Ngaire E. (2002). The Forensic Casebook: The Science of Crime Scene Investigation. Ballantine Books. P.58 Wudka, Jose (1998). The Scientific Method. Available from Read More