Science Buddies: "Ask an Expert"

today in my class room we talked about how when you find some one dead at 10:00 did they actually die at 10:00 or at 1:00p.m which would you say 10:00 when the people found them or 1: when they went missing need your honest opinion?.

some one please help me i am out of answers hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeellllllllllllllllllllllllllllllllllllllllllllllllllllllllllllppppppppppppppppppppppppppppppppppppppppppppppp................................

Ariana,

I moved this thread into the Life Sciences forum since it falls into that category and the experts who'll see it here have more relevant experience. Do you have a science project in mind related to this topic?

Also, please note that at least one expert reads each forum every day, but not always at the same time. You will usually receive a response within 48 hours, and often within 24 hours. Any time you receive a response within only a few hours should be considered good luck -- so posting repeatedly won't get you a response any faster.

Amanda

o.k and yes mamm i want to do a project related to this project

Hello, I am not sure exactly what you talked about in class, so I don't know if this is supposed to be a math problem. I would say the person died some time between 1 and 10 PM, but you won't know for sure without having more information. One method is to measure their body temperature to find the time of death using
Newton's Law of Cooling: T (t) = Te + (T0 − Te ) e^(-kt).
Te stands for the temperature of the environment (where the body was found).
T0 is the initial temperature (normal body temperature of a human).
e=2.71828183.
k is a constant that depends on the object (in your case, a human).
t is time.
T(t) is the temperature after that time.

So, if for example, a dead body with 35 degrees Celsius was found in a room that is 24 degrees Celsius at 10PM. Normal body temperature is 37 degrees Celsius. T(t)= 35. Te= 24. T0=37. You want to find the time t, but you don't have k.

To find k, you will have to have another temperature, so maybe you wait for 2 hrs and the body temperature goes down to 30 degrees. T(t)= 30. Te= 24. T0=35. t=2.
T (t) = Te + (T0 − Te ) e^(-kt).
30= 24 + (35 - 24) e^(-k x 2). Solve to find that k= 0.30307.

Now use the equation again with the bolded values and k.
35= 24 + (37 - 24) e^ (-0.30307 x t). Solve to find that t= 0.55 hrs.
This means that the person died 0.55 hours or about 33 minutes before the time he was found. The answer then is at 9:27 PM.

I'm sorry for this super long and complicated answer, I hope you can understand this.

Also, you said you want to do a project related to this. Well, Newton's Law of Cooling works on other objects as well (hard-boiled eggs) as long as you have all the required variables. But this would be more calculations rather than a experiment.

thank you drowningfish very much i kind of understand it.because we learned about newtons law of cooling.thank you very much.oh and may you help me with this?if you add co2 with qH and trap H2O in it you'ld it explode? :D