Activity 1.1.5: Time of Death Experimental
Design
1. Identify the Problem or Question
How do different ambient temperatures affect the rate of body cooling?
2. Predict a solution to the problem or an answer to the question.
Hypothesis: The rate of cooling will be fastern in a cooler room then a
warmer room because the environmental tempture will effect the rate
of cooling.
The independent variable is: The temputure in the water baths.
The dependent variable is: The rate of body cooling.
3. Design the experiment to be used to test your hypothesis.
Materials:
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1 Vernier Temperature Probe
Goggles
Gloves
Laboratory apron
Oven mitt
Ring stands with clamp
Test tubes
Sodium polyacrylate (also known as waterlock)
Weigh boats
Electronic balance
Thermometer
37˚C Water
Graduated cylinder
Room temperature water
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Principles of Biomedical Science Activity 1.1.5 Time of Death Experimental Design – Page 1
Procedure:
1. Wear the appropriate personal protective equipment.
2. Create the following: A 250 mL beaker filled with 200 mL of water at room
temperature (approximately 20˚C).
3. Obtain one test tube and measure and place 0.1 gram of sodium polyacrylate
into the test tube.
4. Obtain one Vernier Temperature Probe, an analog thermometer, and a ring stand
with clamp.
5. Connect the Temperature Probes into CH 1 of the Ti Nspire lab cradel Telecom
connector.
6. Place the thermometer in the water bath to ensure that they maintain the correct
temperatures. Record this temperature in the Evidence Record table.
7. Attach the Temperature Probes to the clamp on the ring stands.
8. Place 20 mL of 37˚ water into the test tubes. These represent dead bodies.
9. Place a test tube with waterlock representing the dead body in each of the three
water baths.
10. Place a Temperature Probe in the center of each test tube with waterlock.
11. Wait for the temperature sensors to reach the temperature of the waterlock. Click
to begin data collection. Note that the experiment is set to collect data for
20 minutes.
4. Carry out the experiment.
Evidence Record
Assigned
Temperature:
Actual
Temperature of
Water Bath
Maximum
Temperature
of Waterlock
Minimum
Temperature
of Waterlock
(˚C):
(˚C):
(˚C):
Temperature
Change
(˚C):
50˚C
50
51
37
14
Room
temperature
24
37
20.9
-28.9
(0)c
2
33.7
0.5
33.2
© 2013 Project Lead The Way, Inc.
Principles of Biomedical Science Activity 1.1.5 Time of Death Experimental Design – Page 2
5. Analyze the data and observations.
98.4-92.4/1.5=4
Atd=6:00 a.m
6. State the conclusion.
Conclusion:
7. Summary Paragraph
Summary Paragraph:
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Principles of Biomedical Science Activity 1.1.5 Time of Death Experimental Design – Page 3