Blood spatter lab- ALL blood stained papers must have names and labels on them.
The lab directions, tables and questions are to be submitted by each student, individually.
1. Purpose:
2. Hypotheses for transfer, projected and passive blood spatter;
3. Reason for studying blood spatter designs is to recognize how criminalists use the spatter as
evidence. Give two reasons for using spatter as evidence.
4. Materials
Blood material in dropper
Variety of paper types at least 4 paper towel, Xerox , cardboard, poster board and plastic coated
paper- surface/smooth surface
Ruler
Protractor as needed
Scientific calculator with sin -1 function handheld or on laptop
Construct tables as needed in lab-may place on back of paper
LABEL everything- all poster/paper/ with names and angles and heights
DO each noted below with at least 3 different types of paper!
5. Passive blood spatter; drop blood at a 90o angle to surface of paper
Do 5 times at 5 varying heights.
Make each height difference at least 5 in apart.
Observe and record the difference in each drop as height increases.
Label each drop
6. Blood spatter on angle
Hold paper on angle; can measure with protractor.
Drop five drops at varying angles from <90 to 10 or greater- label
Lay out paper and walk a few steps while dropping, dripping blood on paper. Label start and
finish
i.
Calculate each angle with W/L Sin arc; divide W/L use 2nd key and then sin -1 to get angle LABEL
on paper. Angle of impact = ArcSIN of W/L ratio
a)
First calculate ratio (W/L)
b)
You should remember that you can use SIN-1(2nd key) to get degree of AOI.
Show all calculations
7. Projected blood OUTSIDE
Use dropper and flick blood towards paper; move hand as it is projected
Make unique design
8. Transfer blood; do not label transfers
USE GLOVES or objects ; make numerous transfers on paper
9. Determine lines of convergence and in next two blood drops, what type of event could have
occurred to produce each of these patterns?
10. How are blood drops at different heights alike?
How do they differ?
11. How do large volume and dripped volume blood patterns compare?
12. Of what value is large volume of blood patterns to a criminalist?
13. What does a transfer indicate to a criminalist?
14. What does a projected spatter indicate to a criminalist?
15. The value of wet blood from dry is
16. Any two tests for the presence of blood are