Forensic Science 5.1 - Essay Example

Answers Liquid samples are prepared by using a special syringe to inject the evidence into a gas chromatograph. Four methods are used in preparingdebris samples and for processing them to separate the accelerant from the debris. These include: heated headspace, steam distillation, carbon strip or tube absorption, and solvent wash. In heated headspace, the debris is warmed and the vapor that collects at the top of the container is removed for analysis. In steam distillation, water is missed with the debris and heated after which the condensate is removed and analyzed.

Carbon strip involves the use of an activated carbon strip to absorb the vapors from debris and then mixed with a solvent for analysis. Solvent wash is used when the debris cannot be easily vaporized due to high boiling point. Subsequently after sample preparation gas chromatography is used to separate the chemicals for identification and assessment (Gaensslen, 2008).2. There are two main objectives of investigating a fire scene: (1) to identify the cause of fire and (2) its origin. Since fires burn upwards, the burn patterns are important in trying to understand the direction or fire and how it possibly started.

Then points of origin are looked for to analyze the origins of fire.3. Whenever an explosive detonates, it causes much more damage than the usual fire. Explosions are characterized by a special kind of combustion that occurs more quickly and is capable of giving off large amounts of heat quite quickly. Hence, the intensity of an explosion is great. Igniters, primers, or detonators are used along with main charge that causes a lot of damage when they explode.4. Chromatography is common separation and analysis technique common to both in investigating an explosive or fire debris.

Infrared spectrography is more common for analyzing explosives in addition to gas chromatography. However, the nature of an explosion differs greatly from a normal fire. 5. Examination of an unexploded device is different because unlike having debris or other physical evidence, unexploded devices have to rendered safe, examined for all the components, and identified in terms of their chemical make-up. However, exploded devices involve microscopic investigation and gas chromatography.6. Methamphetamine7.

Physiological8. Body fluid or tissue9. Three common club drugs are: MDMA (Ecstacy)GHB (Gamma Hydroxybutyrate)Ketamine10. B11. Trace evidences are small-sized physical evidences that are used to make connections between criminal and/or victim. Transfer materials on the other hand are those that are found on objects as a result of being transferred because of contact (Gaensslen, 2008).12. ForcepsTape liftingMechanical DislocationVacuuming13. Two forms of material evidences are:ClothesVehiclesGlassHair14.

A control sample is important to a successful comparison especially in the case of transferred materials. This is because transferred materials have contact with many other objects. Hence, a control ensures effective comparison by providing a direction and ruling out many possibilities.15. Glass is an amorphous material in nature which means that when it breaks, a pattern can be observed showing the cracks which can count as material evidences. In many instances, the glass can be mixed with other materials such as fibers and hair that can be identified using a stereomicroscope (Gaensslen, 2008).

ReferencesGaensslen, R. (2008). Introduction to Forensic Science & Criminalities. New York: McGraw-Hill.