Practical Forensic Investigation : Written Report and Oral Presentation - Essay Example

1998). Blood also has physical properties which also make it very useful in the investigations. The pattern of blood stains in a crime scene can help forensic investigators to get the origin of the blood, the force of the blood, the distance of the victim from the assailant and the force used plus the nature of the weapon that could have been used in the attack or in doing the felony. Bloodstain pattern interpretation relies on the principles of physics like gravity which explains the movement of the blood drop, viscosity which will explain the behaviour of blood in flowing and surface tension (Eskert.

, William, G,.1998). Also it borrows heavily from forces; adhesive and cohesive forces which will explain the spattering of blood when it hits a surface and furthermore explain why blood will move as a drop. All this is used in coming with credible evidence which can aid in getting to the root of criminal practices. PRACTICAL: TO INVESTIGATE THE BEHAVIOUR OF BLOOD WHEN IT HITS FLAT SURFACES FROM DIFFERENT ANGLES. AIM The practical is aimed at investigating the blood properties and its behaviour when it hits a surface.

It should show the difference between the strikes from the different angles and conclude on the application of the practical in a real life situation. The practical should also bring the aspect of force and the distance between the source of blood and the surface it hits as it also affects the behaviour of the blood. If the distance is short then it means that the force will be less and the vice versa. At the end of the practical we should show the effect of release height on the diameter and shape of the bloodstains.

We should also show the effect of the surface that the blood hits on the shape and size of the blood drop. Other factors that we should explain that affect the size and shapes of the blood drop are; angle of impact and the amount of force used to release the drop. All these can help us to know the origin of the blood, the distance between the victim and the assailant and the direction of victim after attack. METHODS Blood is a sensitive substance and so it needs a lot of care when handling it.

T could contain airborne pathogens or other biohazards such as AIDS and hepatitis A and B which can cause illnesses if not handled with care (James., Stuart, H,.1999). To be safe a PPE (personal protective equipment) was used. The standing clamp was set on 30 inches using degree tables. The degree tables were to be used so as to change the angle of impact as the blood drop struck the surface so we may able to record our results from the different angles. This was important for comparison when measuring the size and direction of the spatter when the blood struck the surface.

The angles to be used were 150, 250, 350, 450, 550, 650, 750 and 850. 40 mm of blood was put in the syringe and then transferred into the pipette. The pipette was the one that was to be used to drop the blood drops on the white paper surfaces. The blood was then dropped from the pipette from a distance of 30 inches on the separate paper surfaces. The results were kept safe waiting to be analyzed. After doing getting the drops using all the angles, the diameters of the drops were measured. FINDINGS AND DISCUSSION When a drop of blood was released to strike a paper at 150, a drop that spattered to one side was produced.

The diameter of the drop was found to be 1.4 cm. from that we can