1.2.2. Time of Death
RQ- Why is determining the physiological time of death often difficult?
Depending on the conditions the body is in, everything changed. Vital functions are internal so it is more difficult to figure out the time of death.
CQ- Based on the results of your experiment, how does ambient temperature affect the rate of cooling of a body after death?
Based on the surrounding temperature, the body will either cool or heat to match its ambient temperature.
Decomposition 36-48 hrs.
body turns greenish in color and may swell/bloat as bacteria breaks down and tissues release gas.
Livor Mortis 0-24 hrs.
pooling of the body following death that cases a purplish red discoloration of the skin; also referred to as lividity. Blood travels to the ground.
Changing temperatures 0-24 hrs.
the body begins cooling after death to match the the surrounding temperature. Algor Mortis.
Algor Mortis
the change in body temperature after death
Rigor Mortis
the stiffening of joints and muscles after death
Legal Time of Death
the time of death recorded on the death certificate; based on when the body was found or physically pronounced dead
Estimated Time of Death
the time the medical examiner estimates that the death occurred
Physiological Time of Death
the time when the decedents vital functions actually ceased
Goals
1. Evaluate evidence to determine time of death 2. Analyze the results of a scientific experiment
Insect activity 1-145 hrs.
Can provide clues about how long a person has been dead and the presence of eggs, larva, or full-grown bugs provide a timestamp for how long the body has been decaying
Rigor Mortis 2-4 hrs.
Muscles contract/ stiffen and full rigor mortis is present in the body in 8-12hrs. Rigor fades 36-48 hrs. later when decomposition begins.
CQ- Why is determining time of death such a complicated process?
There are so many factors that relate to death and there will always just be a rough estimate of time of death due to temperature, livor mortis, etc.
Clouding of corneas 3-4 hrs.
The corneas (clear part of eyes) become milky or cloudy.
