Blood Analysis

Nancy Cox

Marble Hill International School, Bronx

Summer Research Program for Science Teachers

August 2009



OBJECTIVE: Students will be able to identify and describe various bloodstain and spatter patterns, and explain their importance in Forensic Serology.


How are bloodstains and spatter patterns examined?


Handouts and Blood work activity labs (Ward's Blood Spatter Analysis Kit).


Students will be given handouts of bloodstains and asked to answer the following questions.

  1. Why do you believe bloodstains/spatters are important in a criminal investigation?
  2. From which direction are the bloodstains traveling?
  3. From what angles were blood patterns A and B made?

 DEVELOPMENT (Elicit Responses From Students Based on the Motivation)

Bloodstains and spatter patterns are important because they can interpret and reconstruct the events that must have occurred to have produced bleeding.  Investigators examine the following:

1.      Location of the blood stains and spatters.

2.      Distribution of the blood stains and spatters.

3.      Appearance of the blood stains and spatters.

4.      Surface Texture (Porous vs. Non-Porous)

*Porous = absorbent; Non-Porous = non-absorbent

5.      Direction of travel (towards what direction is the blood traveling)

6.      Impact angle of bloodstains and spatters on a flat surface

7.      Origin of bloodstains and spatters (point of convergence)


Students will be instructed on lab activities that provide practical understandings of the above.

  1. Single blood drop from 3 different heights.
  2. Multiple blood drops (overlaid) from the same height.
  3. Walking blood drip patterns, wipes, swipes, and other transfer stains.
  4. Arterial spurts.
  5. Cast-off Spatter.
  6. Blood drops on different surfaces from the same height.
  7. Blood drops at different impact angles from the same height.
  8. Blood drops at different impact angles from different heights.
  9. Medium and high velocity impact spatter. 

Lesson Plan Unit Review:  Student Assessment Questions 1-11 (Ward's Blood Spatter Analysis Kit).


3.1, S1d, S5f, S6a, S6b, S6c, S7a