Are small drops that break from the parent drop and can show direction of blood travel?
Satellite Spatters – Small drops of blood that break of from the parent spatter when the blood droplet hits a surface.
Is a drop of blood physical or trace evidence?
Examples: strand of hair, fingerprint, DNA, drop of blood, pollen, gunshot residue a) Physical evidence: synthetic fibers, weapons, bullets, shell casings, paint chips, documents, imprints and prints (shoes, tires, etc.), tool marks, soil, drugs, etc.
What causes falling droplets of blood?
The spherical shape is caused by the surface tension of the blood. Surface Tension causes the blood drop to pull itself in; both horizontally and vertically. The blood drop will settle into a spherical shape, as a result of the surface tension.
What are small droplets of blood called?
Satellite Spatter —
Satellite Spatter — Small droplets of blood that are distributed around a drop or pool of blood as a result of the blood impacting the target surface. Spatter — That blood which has been dispersed as a result of force applied to a source of blood.
What type of surface causes blood drops to hold together?
A smooth surface, such as tile or linoleum, will cause little distortion of this spherical shaped drop, whereas a rougher surface, such as carpet or concrete, disrupts the surface tension and causes the drops to break apart.
What 3 things determine the shape and size of a puddle when blood is dropped onto a surface?
The shape and size of the puddle depends on the amount of liquid, the height of the container, and whether you spill on carpet, wood, linoleum or some other surface. In general, more liquid, or a fall from a greater height, will make a larger puddle.
Is blood considered trace evidence?
In addition to microscopic evidence, the trace evidence section also deals with physical evidence such as tire and shoeprint impressions. These can be found in several different types of materials, such as paint, blood, soil and dust.
How is blood evidence properly collected?
Liquid blood evidence is generally collected from blood pools but can be collected off of clothing as well, using a gauze pad or a sterile cotton cloth. Once the sample is collected it must be refrigerated or frozen and brought to the laboratory as quickly as possible.
What is the fastest free falling blood can travel?
25.1 ft/sec
Saturation Pattern – Bloodstain pattern resulting from an accumulation liquid on an absorbent material. Target – A surface upon which blood has been deposited. Terminal Velocity – The greatest speed to which a free falling drop of blood can accelerate in air; This speed is 25.1 ft/sec.
What angle was a circular drop of blood dropped at?
As the angle of impact changes, so does the appearance of the resulting stain. A blood drop striking a smooth surface at a 90° angle will result in an almost circular stain; there is little elongation, and the spines and satellites are fairly evenly distributed around the outside of the drop.
What type of evidence is trace evidence?
The Trace Evidence Unit (TEU) identifies and compares specific types of trace materials that could be transferred during the commission of a violent crime. These trace materials include human hair, animal hair, textile fibers and fabric, rope, soil, glass, and building materials.
What are the five major types of trace evidence?
Although the types of materials that might be used as trace evidence are nearly unlimited, hairs, fibers, paint, glass, and soil are the most common types analyzed in the microscopy laboratory.
How long does it take for blood to dry up?
Blood begins to dry approximately 50 seconds after it has been deposited [13]. The center of a blood droplet or pool is the last part to dry as blood droplets dry from the exterior region to the interior or central region.
How long can dried blood last?
Hepatitis B virus can live in dried blood for up to a week. Hepatitis C virus can survive for up to four days. Work surfaces that become contaminated with blood or other body fluids* can expose you to a bloodborne disease through cross-contamination.
What happens when blood is dropped onto a surface at a ninety degree angle?
A blood drop striking a smooth surface at a 90° angle will result in an almost circular stain; there is little elongation, and the spines and satellites are fairly evenly distributed around the outside of the drop. Below 75°, spines begin to become more prominent on the side of the spatter opposite the angle of impact.
What type of evidence is blood evidence?
Physical Evidence is any object or item that establishes that a crime has been committed or establishes a link between a crime and its perpetrator or crime and its victim. Examples of physical evidence include a document, a hair, fibers, fingerprints, soil, and blood.
