Ask the Dreadlocked Science Geek

[dreadgeek]

Originally Posted by Linus

To tag to June's question I was just reading this: http://www.huffingtonpost.com/robert..._b_810936.html

Since humans are known to contain "energy" (about 20 watts) and since energy cannot be destroyed or created but altered, then when we die where does that 20 watts go?

[/I]

Reason Two. Conservation of energy is a fundamental axiom of science. The first law of thermodynamics states that energy can't be created or destroyed. It can only change forms. Although bodies self-destruct, the "me'' feeling is just a 20-watt cloud of energy in your head. But this energy doesn't go away at death. A few years ago scientists showed they could retroactively change something that happened in the past. Particles had to "decide" how to behave when they passed a fork in an apparatus. Later on, the experimenter could flip a switch. The results showed that what the observer decided at that point determined how the particle behaved at the fork in the past.

I highlighted the relevant part in red.

Actually Lanza gets the First Law of Thermodynamics almost *precisely* wrong. Yes, the common simplification of the law is that energy cannot be created or destroyed but that's not *precisely* what is meant and you cannot derive Lanza's conclusion from the actual, formal definition of the law.

So what does the law state? In any system where work is performed the total amount of energy of the system (work performed plus loss from inefficiencies) is conserved. What this means is that you cannot get more energy OUT of a system than you put IN to a system. The problem with Lanza's explanation is that he doesn't say that, for instance, physicists are talking about a closed (isolated) system. The total energy amount of the Universe, for example, is actually fixed. Whatever that quantity is, the Universe is a closed system (no energy can be introduced from outside), but the Earth, for example, is not a closed system. Energy is being introduced to the system all the time by way of sunlight.

The second problem is that the 20 watts he mentions can be accounted for WITHOUT it having to go to some mysterious place. The 20 watts or so that your brain uses stops (becomes potential energy) when all of your metabolic processes cease. So then various microbes and worms come along and decompose (eat) your mortal remains. They transfer all of the energy stored in your cells to *their* cells (that is what eating does, it is simply a way of taking the energy from one living thing and making it useful to another living thing). This actually satisfies the requirement that energy is conserved. The energy does not exit the Universe (because it can't be destroyed*) but neither does this energy continue to persist in some kind of coherent state. The 20 watts of energy that Dr. Lanza is invoking is a product of your neuronal activity. Once the substrate that generates that activity no longer functions, the total energy of the system that is described by your body starts to go to its most natural (i.e. disordered) state with a consequent loss of energy.

Dr. Lanza pulls one of these tricks that is always like nails on chalkboard. In the service of his ideology, he invokes some commonly recognized but not well understood (by laypeople, I mean) principle in physics and then offers what seems like a plausible explanation but is actually glossing over the issue. He then claims that this or that physics principle proves that his particular idea/ideology/belief is backed up by science.

Cheers
Aj