Glass
What is the main ingredient in glass?
Sand / silicon dioxide
What kind of evidence is fabric?
Trace Evidence
What are three types of formed elements in blood.
RBC, WBC, and plateletes
What is the goal of a polygraph test?
Why blood type is the universal donor?
O-
What is the Becke Line? What does it show?
a "halo" that can be seen on the inside of the glass, indicated that the glass has a higher refractive index than the liquid medium.
1. Plant-Derived Fibers
2. Animal-Derived Fibers
3. Manufactured Fibers
What is the formula to calculate the angle of impact of blood spatter?
W/L, then inverse sign the number.
About how long is a polygraph?
2 hours
What is plasma composed of?
55% plasma (mostly water) and 45% formed elements (RBC, WBC, platelets)
What is the most common type of glass encountered by forensic scientists?
"Flat" / float glass > the glass used in windows and doors.
Natural vs manufactured fibers.
Natural = derived entirely from plant or animal (would have medulla and cuticle pattern) sources
Manufactured = made from long chains of molecules called polymers
The main function of blood.
Transporting oxygen and nutrients throughout the body.
What are the four types of questions asked during a polygraph?
1. Comparison
2. Relevant
3. Symptomatic
4. Neutral
What does the (+) symbol mean in blood typing? Why is it important?
It represents the Rh factor. Women who are pregnant and is Rh- and the baby is Rh+, her blood would attack the baby's blood and blood transfusions.
What is the index of refraction formula and snell's law?
Index of refraction = n=c/v
Snell's Law = n1*sin(1st angle) = n2*sin(2nd angle)
1st angle = angle of incidence
2nd angle = angle of refraction
What are three types of derived fibers?
What is the area of convergence?
By drawing a line through the long axis of a group of bloodstains, the point of convergence can be determined. Where the lines of the group os stains intersect one another the convergence point can be established.
What are the three types of tracing? What do they each represent? (The different lines on the graph)
1. Blue = nomograph *
2. Green = EDA = electrodermal activity
3. Red = cardiovascular (looking for vertical rise from stimulus)
Blood type AB would have what antibodies in it?
No Anti-A or Anti0b antibodies
What are three types of glass and their characteristics?
1. Float = "flat" glass > the glass used in windows and doors.
2. Soda-Lime Glass > silica itself makes a glass (fused silica), Na2O (soda), lowers melting temp & CaO (lime) increases stability.
3. Borosilicate > over 5% B2O3 (boronoxide) added to the silica
4. Light sensitive eyeglasses lenses > contains collodial particles of silver, halide, identified by exposure to UV light
5. Tempered glass > rapid cooling add strength, dices when broken
6. Laminated glass = "sandwiched" around plastic, in windshields
What are the three types of manufactured fibers?
1. Rayon = 1st artificial fiber from wood (most common artificial fiber)
2. Acetate = artificial from wood (satin)
3. Nylon = 1st synthetic fiber
4. Acrylic = synthetic wool
5. Polyester = most common synthetic fiber
Four factors that affect blood spatter.
1. Speed and height
2. Volume
3. Surface
4. Angle