Angled Blood Drops Lab
What effect does the angle of impact have on blood droplet size and shape?
In this investigation you will examine the size and shape of blood droplets dropped at several
angles.
General procedure​: ​Observe the size and pattern changes with drops landing on different
angled surfaces by measuring drops provided to you on the provided data sheets.
1. Mark the three drops with Notability tools. Measure the length and width of each
droplet. (mm) Ignore the tail area, just measure the oval area. Find the average of the
three on each paper and observe the shape and size of drops in your data chart. Use
terms from spatter notes in your observations. (spines, target, tail, etc.) Complete the
data table for each surface angle before moving to the next.
2. Answer analysis questions, using Notability.
3. Submit on Schoology after complete; before the due date.
Data Table​: Complete in notability.
Drops
Impact
Angle to
Vertical
1
90º
2
90º
3
90º
average
1
75º
2
75º
3
75º
average
1
60º
2
60º
3
60º
average
Length
(elongation)
(mm)
Width
(mm)
Shape and observations of bloodstains
for each ​impact angle group
(terms: tail, spines, satellites, oval, round)
1
45º
2
45º
3
45º
average
1
30º
2
30º
3
30º
average
1
15º
2
15º
3
15º
average
Analysis Questions​:
1. Describe the relationship between the elongation of the drops and the impact angle.
2. Describe the relationship between the width of the drops and the impact angle.
3. Describe the tails created. At what angles do the tails form?
4. Infer​ information about a crime scene drop impact angle that was measured at 8 mm
elongation and 5 mm width. ​Predict​ the impact angle.
Would this drop have a tail?
5. Conclusion: What impact does the impact angle have on the size and shape of blood
drops?
a
flat
surface
Disclaimer
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