Thermodynamics is a word we’ve probably all heard but don’t use much. Certainly, many of us aren’t sure what it means. It would be good if we did because, after all, it’s the law. Actually, there are four laws of thermodynamics, of which two are worth talking about. The first law is most likely to have familiarity to most of us. It is frequently referred to as the law of conservation of energy.
Energy has several forms: mechanical, electrical, radiant (e.g., light), heat, acoustic (sound), and nuclear. The first requires that the energy of an isolated system remain constant. It may be converted from one form to another, but the bookkeeping must account for it all and it is constant. Most systems we witness are not isolated but are exchanging energy with the surroundings in numerous ways.
The internal combustion engine is a thermodynamic system we should be able to relate to. The fuel is a source of stored chemical energy. In the combustion chamber, combustion is the chemical reaction of the fuel with oxygen, converting that chemical energy into mostly heat but also light, which you don’t see, and acoustic energy that you hear. The heat causes the gases in the chamber to expand and push the piston down, some of the heat are absorbed by the
cylinder block and dumped into the atmosphere by the cooling system.
We can easily hear where the acoustic energy goes. Some of it also goes out the exhaust pipe along with some of the heat energy. The first law requires that when all of these components are added up, they must equate to the chemical energy that was extracted from the fuel.
The second law is more abstract and less evident in our everyday observations. That will be where the theological implications occur to me. It states that thermodynamic processes proceed in one direction only and are not reversible. For example, helium in a balloon will spontaneously gush out into the atmosphere, but it won’t go back of its own accord. Heat will flow from a hot region to a colder one but not the other way around. In the case of the filled balloon, when the helium is in the balloon and not elsewhere, we can consider that a certain state of order. We know where the helium is and where it isn’t. Once it escapes, we no longer know exactly where it is; that’s disorder. The physical measure of this disorder is called entropy, and it has the units of energy divided by absolute temperature.
A very general statement of the second law is that any thermodynamic process will always result in a net increase in the disorder of the universe. That’s a bleak prediction. The logical conclusion is that we are using up the order in the universe and ultimately it will run out. Perhaps that is something for environmental zealots to ponder.
Should we strive to conserve the order in the universe since it is not renewable? This is where the theological implication occurs to me. Since we are using up the order that is present in the universe, how was it created in the first place? Is that not the hand of God?
There are two other laws of thermodynamics, the zeroth and third laws. I won’t talk about them unless you ask me. That information is on a need-to-know basis only.
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