Activity 8-4
Blood Spatter Analysis: Effect of Height on Blood Drops Teacher Notes
Teaching tip:
Recipe for simulated blood:
Red food coloring, glycerin and water or
Kayro® syrup, red food coloring and water
Dispense by way of small polyethylene dropping bottles
Notes:
Have student teams of four divide into pairs for measuring the heights for the blood drops. One group of two students could do measurements of 25, 50 and 100 cm and the other pair within the group does heights of 150, 200 and 250 cm.
Dispense 1- 3 drops from various heights 25, 50, 100, 150, 200 and 250 cm
Use separate cards if necessary.
Label card before dropping blood on them.
Use lots of newspaper. The floor will stain.
Have each team designate at least one team member to oversee that drops are
dispensed from the correct height.
Do not rush students – provide extra 5 x 8 cards as necessary.
Droplets of simulated blood will probably not dry for several days. Do not stack the
spatter cards.
Questions
1. Is there a relationship between the height from which the blood is dropped and the size of the blood-spatter droplets? Support your answer with data. Yes
2. True or False: As the height from which the blood is dropped increases, the size of the blood spatter continues to increase. Support your answer with data. Yes
3. Blood is dropped from heights of 25 cm and 250 cm. Compare and contrast the outer edges of blood droplets produced from these two heights. The outer edges of the blood dropped from 250 cm will have more satellites.
4. Examine the blood spatter produced by dropping blood from the six different heights. Is there a relationship between the height from which the blood is dropped and the number of satellites produced? Support your answer with data. Yes
5. Compare your results with your classmates.
a. Were your results similar to those of your classmates? If not, how did they differ? Answers will vary.
b. If someone accidentally dropped two or more drops of blood in the same location, what effect would it have on the blood-spatter pattern? The second drop might mask the pattern of the first one.