Life, Death, and Energy Conservation
Most recent answer: 10/22/2007
- Ted. M (age 19)
Valporaiso, IN
You're kidding- your physics teacher brought this up? By energy, we mean a specific measurable physical quantity, which shows no particular dramatic difference when something dies. For warm-blooded creatures, some thermal energy gradually leaks into the environment, if the environment happens to be a bit cooler than living body temperature. We don't mean all sorts of interesting features of how something behaves, which of course do change dramatically when something dies. So conservation of energy doesn't even lead to any interesting questions in connection with death, much less any imaginative answers.
Mike W.
(published on 10/22/2007)
Follow-Up #1: energy and life
- Bob T. (age 47)
Bellefonte, PA
Maybe an analogy will help. When your car is running, there's an interesting flow of energy of a variety of types through the engine, electrical system, and so forth. When the car is off, most of that flow ceases. The energy itself doesn't disappear or do anything surprising or hard to explain. The thermal energy in the hot engine gradually leaks into the environment, etc.
Any of our basic laws might ultimately turn out to be wrong in some circumstances. In testing the laws, however, we try to look for circumstances where there's some theoretical reason to suspect we're near the edge of their range of validity. Just randomly picking events and guessing, for no particular reason, 'maybe the laws don't work here' is a pretty inefficient way to proceed.
Mike W.
(published on 10/22/2007)
Follow-Up #2: vis viva?
- JV (age 30)
MA
Whatever is special about life, all the amazing organized activity, the subjective sense of consciousness, and so forth is not the same thing as 'energy'. We have no physical reason to believe that those interesting and important other attributes are 'conserved', even though energy is.
Mike W.
(published on 10/03/2009)
Follow-Up #3: Energy and life revisited
- Kormak (age 23)
Canyon Hills, CA, 92532
My claim is that there is no known conserved quantity which shows any unusual behavior when a living thing dies. There are things that are conserved, like energy, but they continue to be conserved in these processes. There are important things we care about that change, but there's no evidence that those things are conserved.
What exactly do you want to know?
You're invited to try to make some version of this question that:
1. Actually means something.
and
2. Makes no false assumptions.
Mike W.
p.s. I edited out the gratuitous and incorrect middle initial you gave me.
(published on 01/31/2011)
Follow-Up #4: What happens to neuron energy on death?
- SW (age 41)
Baton Rouge, LA
2. I'm not sure I know exactly which processes you are referring to here. The active processes stop, since there's no incoming free energy to drive them. Passive diffusion processes continue as things approach equilibrium.
3. This is a very philosophical question. I'm not comfortable with some of the implicit assumptions, in particular the idea that mental processes can be divided up into discrete thoughts with well-defined starting points. If one were to look at a system where such assumptions might provide a better model, a digital computer, the last thing one would worry about is energy conservation. All the little circuit elements obey energy conservation in a simple freshman-physics manner. Their collective behavior is interesting anyway.
Please follow-up if I've missed the point of some of your questions.
Mike W.
(published on 03/24/2011)
Follow-Up #5: Energy and power in human body
- Christopher (age 21)
Whittier ca USA
First of all, do not confuse power with energy. Power is the rate of change of energy, expressed in Watts. The average power output of a human body at rest is between 90 and 100 Watts. This about the same as a fairly bright incandescent light bulb. However, this amount of power is used just to keep the bodily functions going, not to do useful work. Its net result is to heat up the surroundings. It is claimed that a good long distance bicycle rider can have a sustained power output of 400 Watts or so. I'm not sure, I've never tried it.
As for your philosophical questions about life, death, and energy conservation, I invite you to read some of our previous Q's & A's on this subject. You can type in 5597 into the search box of the main page to find them.
LeeH
(published on 08/22/2012)
Follow-Up #6: energy, life, and death
- Jennifer (age 44)
Peoria,IL
Everything you say sounds consistent with what we know of physics.
Mike W.
(published on 08/14/2013)
Follow-Up #7: where does life energy go?
- Marilyn deVito (age 62y)
akron, Ohio, United States of America
Yes, when a mammal dies it is usually surrounded by things that are cooler than body temperature. So a little heat leaks out into those surroundings. Also, most of the chemicals we're made of are not in low-energy states. They gradually fall apart, oxidize, etc. and the energy released also trickles out into the surroundings.
Mike W,
(published on 03/09/2014)
Follow-Up #8: Where does our energy go?
- CD (age 40)
Sacramento, CA USA
Actually, any heat energy on the Earth's surface does escape to far space, in the form of (mostly infrared) radiation. The way greenhouse global warming works is by slowing that escape process, so the Earth has to get hotter before the escaping radiation balances the incoming radiation from the Sun.
Mike W.
(published on 05/02/2014)