What is Blood?Blood is the fluid medium of the circulatory system. It is made up of plasma, erythrocytes, leukocytes, and platelets. Plasma is made of 90% water and 10 % of dissolved fats,proteins,waste products. Erythrocytes are red blood cells. Leukocytes are white blood cells. Platelets are cell fragments that help in clotting.
|
This is a visual of blood spatter which occurs when a type of wound was made. I chose this because this was my favorite part of the unit because I found it the most interesting.
|
|
How can blood be used to identify individuals? |
There is four types of blood. A,B,AB,O. Blood typing is used by scientists by taking the blood found at a crime scene and seeing if it matches that of a suspect. They do thing by using chemicals that react with the blood causing it to change color. They also use a chemical that may cause the blood to clump. If it clumps that means the blood is say A+ if it doesn't clump it would be A-. That is called the rH factor. Using blood typing is a great piece of physical evidence because it can always be traced back to the “owner”, where with fingerprints you can sometimes get partial prints which are harder to go off.
|
Reflection: At the beginning of the unit I was very interested to learn about blood and how exactly it is used to solve crimes because there is many ways it is analysed. at the end of the unit I enjoyed learning about everything from blood trails to blood spatter. I was left wondering exactly how much blood is in the human body.
|
How can blood spatter be used to recreate a crime scene? |
The blood spatter at a crime scene can help find the origin of the blood stain, the distance of a blood stain from a target, the position of the victim, the speed of the bullet. Blood can look different on different surfaces like on rough surfaces a blood drop has “rough” edges but on a smooth surface it is more round. The blood spatter can be used to identify the type of weapon used or the victim by the type of blood spatter. If it is small, almost mist-like it is a high velocity weapon such as a gun. Medium sized drops are caused by people power such as the swing of a hammer. Low velocity blood droplets are usually caused by slow blood maybe dripping of a cut of the finger. The angle of impact can affects the length of a blood droplet by making the blood droplet longer or shorter depending or the angle of say a gun shot.
|