Saturday, August 6, 2011

Blood splatter activity: part 2!

Analysis of blood splatters

From the previous experiment, I gathered that all my hypotheses, namely:
- The higher the angle of elevation, the longer the blood splatter
- The higher the angle of elevation, the narrower the blood splatter
- The further the origin of the blood splatter, the wider the diameter of the blood splatter
were true.

Explanations
Height:
The height would affect the velocity of the blood, since higher height means the blood has more gravitational potential energy (which could then convert to more kinetic energy). Higher velocity will affect the diameter of the blood.

Angle of impact:

Since the blood splatter is elongated, the width becomes narrower. The angle of impact will increase when the difference between the length and width is greater (since sin is a ratio of opposite/hypotenuse)

Another factor that affects the blood splatter is the texture. Taken from rambio: Rough surfaces have protuberances that rupture the surface tension of the blood drop and produce spatter and irregularly shaped parent strains with spiny or serrated edges. Also, the volume of blood would naturally cause a bigger blood splatter.

According to this, I know that analysing the blood splatters can probably tell us the origin of the attack (the point where the assailant stabbed the victim). Looking at the slide on rambio, it can also tell:

• Type and velocity of weapon
• Number of blows
• Handedness of assailant (assailants tend to strike with their dominant hand on the opposite side of the victim's body)
• Position and movements of the victim and assailant during and after the attack
• Which wounds were inflicted first
• Type of injuries
• How long ago the crime was committed
• Whether death was immediate or delayed
• Blood spatters can lead to the recreation of a crime because of how blood behaves (which would be based on knowing the origin of attack :D)

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