Activity 8-4
Blood Spatter Impact Angle Teacher Notes
Teaching Tips:
25 cm is the distance from the impact point on the card not the floor.
Tell students to move their hands between drops.
Try not to hit the same place twice.
Use a new card for each new angle.
Use two clipboards (if available) so one card can be drying while placing drops on the
next.
Obtain a paper towel and wipe the bottle mouth before dropping liquid.
Alternate positioning of clipboard. Prop clipboard against a table leg and tape bottom
edge to floor for more precise angling.
Be sure to allow each card to dry before removing from clipboard.
Label each card with an arrow pointing in the direction drop is falling. If unsure, turn
card over and notice where bleeding through has occurred. This is the bottom of
the drop.
Questions:
1. How accurate were you in obtaining the desired angles of impact?
Answers will vary.
2. How would you account for any differences between your actual angle of
impact determined by measuring your blood spatter droplets length and width
with your expected angle of impact as determined by your clipboard set-up?
Incorrect placement of protractor in deter mining angle, human error.
3. Provide an example of how knowing the actual angle of impact could help
police solve crimes.
The determination of actual position of individuals involved in a conflict can be
used to corroborate stories or point out discrepancies.