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PROCEDURE

Part A: Vertical Drip Pattern Recognition

Materials Needed per Group:

Simulated Drip and Projected Blood
Meterstick
2 5 x 8 notecards
Metric Calipers or 15 cm ruler calibrated in mm.
10 mL graduated cylinder

Part 1: Single Blood Drop Patterns

Be sure to familiarize yourself with the glossary terms on the previous pages.

1. Hold the bottle of Simulated Drip and Projected Blood upside down in a vertical position so that the dropper end is 15 cm from the target surface (card).
2. Gently squeeze the bottle so that one drop is released from the bottle at the 15-cm height and lands on the card.
3. Mark this specimen as vertical drop at 15 cm.
4. Reposition the blood bottle so that the tip is 30 cm from the target surface and next to the previous drop. Repeat Steps 2 and 3, labeling for the correct height. Try to get three drops across one card.
5. Generate the remaining blood drops at the vertical heights listed in Data Table A using the same procedure.
6. Briefly allow the blood drops to dry.
7. When blood drops are dry, measure the diameter of the circular part of the drop in millimeters (Figure 1). If there are spines or protrusions on the drop, disregard them as part of the measurement. Record your measurements in Data Table A.

8. Make a sketch of each drop in Data Table A, making note of any spines or protrusions in the drop.

Part 2: Multiple Blood Drips Pattern Recognition

1. Using the Simulated Drip and Projected blood bottle, drip a single drop of blood onto a target surface from a height of 30 cm. Do not move your hand from the 30-cm position. Drop a second drop of blood onto the first. Note any change in the blood drop pattern after dropping the second drop into the first. Record your observations in Data Table B.
2. Drop a 3rd blood drop from the 30-cm position so that the drop lands on the stain from the first two drops. Record your observations.
3. Repeat the procedure until you have mixed a total of 4 blood drops. Record your observations.
4. If possible, save the target surface and allow it to dry overnight. Label the surface multiple single vertical blood drops.
5. Obtain a clean target surface (multiple cards may be necessary). Place approximately 2-3 mL of Simulated Drip and Projected Blood into a 10 mL graduated cylinder. Position the cylinder 30 cm above the target surface, and pour the entire volume of blood all at once onto the target surface. Observe the pattern and record your observations in Data Table B. Save the stain pattern and al low it to dry overnight. Label the stain ‘large volume vertical drip’ pattern.

Data Table A

Data Table B

Part B: Vertical Drips on Various Surfaces: Pattern Recognition

Materials Needed per Group:

Simulated Drip and Projected Blood

Meterstick

5 x 8 notecard

Computer paper

Cardboard

Paper bag (such as a paper grocery bag)

Plastic bag (such as a plastic grocery bag)

A non-porous surface such as: painted wood or Plexiglas®

1. Using the 5 x 8 notecard as the target surface, hold the Simulated Drip and Projected Blood bottle upside down in a vertical position so that the dropper end is 30 cm from the target surface(card).
2. Gently squeeze the bottle so that one drop is released from the bottle at the 30 cm height and lands on the target surface.
3. Observe the pattern and record in Data Table C.
4. Repeat Steps 1-3 using the other materials listed in the table as target surfaces.

    

    

   Data Table C

    

   Target Surface Material	Description and Sketch
   5 x 8 Notecard
   Computer Paper
   Cardboard
   Paper Bag
   Plastic Bag
   Non-porous Surface____________

    

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