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Sunday, 18 September 2016

Does thermodynamics matter?

To put it another way, do ordinary folk need thermodynamics, or an understanding of it? C. P. Snow, later Lord Snow, certainly thought they did, because, as he saw it,  thermodynamics is an area that matters intensely.

As a scientist who also wrote literary novels (as did his wife, Pamela Hansford Johnson), Snow was very aware of how ‘the other side’ saw science, and vice versa. Here, Snow is characterising the attitude of scientists to the ‘arts culture’, in his first entry into this arena, his lecture called The Two Cultures:
…the whole literature of the traditional culture doesn’t seem relevant…They are of course, dead wrong. As a result, their imaginative understanding is less than it could be. They are self-impoverished.
But what about the other side? They are impoverished too—perhaps more seriously, because they are vainer about it. They still like to pretend that the traditional culture is the whole of ‘culture’, as though the natural order didn’t exist. As though the exploration of the natural order was of no interest either in its own value or its consequences…
As with the tone-deaf, they don’t know what they miss. they give a pitying chuckle at the news of scientists who have never read a major work of English literature. They dismiss them as ignorant specialists. Yet their own ignorance is just as startling. A good many times I have been present at gatherings of people who, by the standards of the traditional culture, are thought to be highly educated and who have with considerable gusto been expressing their incredulity at the illiteracy of scientists.
Once or twice I have been provoked and asked the company how many of them could describe the Second Law of Thermodynamics. The response was cold: it was also negative. Yet I was asking them something which is about the scientific equivalent of: Have you read a work of Shakespeare’s?
I now believe that if I had asked an even simpler question—such as, What do you mean by mass, or acceleration, which is the scientific equivalent of saying Can you read?—not more than one in ten of the highly educated would have felt that I was speaking the same language.
Sir Arthur Eddington thought thermodynamics mattered very much to scientists:
Eddington was always at his best when he was having fun with science: “Electrical force is defined as something which causes motion of an electric charge; an electrical charge is something which exerts an electrical force.”
That, however, was bettered by this comment, also from his book, The Nature of the Physical World:
The law that entropy always increases—the second law of thermodynamics—holds, I think, the supreme position among the laws of Nature. If [your pet theory of the universe] is found to be contradicted by observation—well, these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation.
So, yes, thermodynamics matter. It would be worth asking a climate change denier who babbles (as they all do) some drivel about the uncertainty of science, one of Snow's questions.

Oh, and if you aren't sure what the second law says, try this: In any spontaneous process, there is always an increase in the entropy of the universe.

Another way of saying this is to assert that there can never be a 100% efficient (or perfect) heat engine. Another form of the law states that heat flows spontaneously from a hot object to a cold object. Heat will not flow spontaneously from a cold object to a hot object.

If you understand thermodynamics, you can answer this:

You have a perfectly insulated room, and inside it, there is a refrigerator. It has been switch on, and the door had been wedged open. Now:

  • Does the room get cooler? or
  • Does the room get hotter? or
  • Does the temperature stay the same?

This one tricks a lot of people, and the odds are that it will fool climate change deniers as well.  Nobody who is unable to answer this should speak about climate matters.

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