Comparisons – Page 38 – Science-Education-Research

heat dissipation is like wealth redistribution

An example of an analogy used in popular science writing:

"…imagine that instead of large numbers of air molecules moving with different energies, there are crowds of jostling people with different numbers of coins in their pockets. Individuals in the crowd move in random directions but only advance one or two paces before bumping into another person. In this analogy, a fast molecule with many energy units is represented by a person with a large number of coins, a slow one by a person with a small number. A hot oven in a cool room can thus be seen as a small group of rich people bunched together in the corner of a large room full of much poorer ones.

Continuing the analogy, the equivalent of the temperature oof each of the two groups is the average of wealth of its members. Some individuals in each group are richer or poorer than the average, just as with gases of two different temperatures some particles are moving quicker or slower than the average. The equivalent of a fast molecule bumping into a slow molecule and losing some of its energy is a rich person bumping into a poor person and handing over some of his coins, making the rich person poorer and the poor person richer…."

Paul Sen (2022) Einstein's Fridge. The science of fire, ice and the universe. William Collins.

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Many examples of science analogies are listed in 'Creative comparisons: Making science familiar through language. An illustrative catalogue of figurative comparisons and analogies for science concepts'. Free Download.

gas molecules are like frantic bumper cars

An example of a simile used in popular science writing:

"Gas molecules are basically tiny spheres or clumps of spheres in constant collision, like frantic bumper cars. Although an individual molecule is moving rapidly, it has barely gone any distance before it collides into another one, and its journey is deflected."

Paul Sen (2022) Einstein's Fridge. The science of fire, ice and the universe. William Collins.

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Many examples of science similes are listed in 'Creative Comparisons: Making Science Familiar through Language. An illustrative catalogue of figurative comparisons and analogies for science concepts'. Free Download.

heating is like moving noisy people

An example of an analogy used to explain a principle in a popular science book:

"The idea that the same amount of heat causes a greater change of entropy in a cold place than a hot one can seem strange. But consider this as an analogy: A noisy, crowded pub is next to a a quiet library. Five rowdy people leave the pub. The din drops but by an indiscernible amount. The five stumble into the library. The noisiness there increases noticeably. When a group of raucous people enter a quiet place, the increase in disruption there is much greater than its fall in the boisterous place form which they came.
Similarly, when a quantity of heat flows out of a hot room, the fall in entropy there is smaller than the increase that occurs when the heat enters a cold room."

Paul Sen (2022) Einstein's Fridge. The science of fire, ice and the universe. William Collins.

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heat is sucked out of the piston cylinder in an engine

An example of a metaphor (to an alternative conception) used in popular science writing:

"For an engine to keep going, some of the work created during expansion must be sacrificed, pressing the piston back to its starting position…heat must be sucked out of the cylinder into a sink in this compression stage."

"The ideal refrigerator takes the fifty calories' worth of work from the ideal engine, sucks fifty up from the sink, and pumps one hundred calories into the furnace."

"Behind the refrigerator's inner wall is a network of pipes called an evaporator. The coolant evaporates inside it, sucking heat out of the device's interior at a constant temperature of 4˚C."

Paul Sen (2022) Einstein's Fridge. The science of fire, ice and the universe. William Collins.

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Many examples of science metaphors are listed in 'Creative comparisons: Making science familiar through language. An illustrative catalogue of figurative comparisons and analogies for science concepts'. Free Download.

Read about common ideas about sucking being contrary to science

heat engines are like water mills

An example of analogy used by a scientist:

"Carnot had analogised heat engines to water mills. In the latter, water creates energy in the form of work as it streams downhill. In heat engines caloric fluid was supposed to do the same as it flows form hot furnace to cool sink. The same amount of both substances leaves their respective devices as enters. Neither water nor caloric fluid are destroyed.
Clausius abandoned this comparison. Though water enables a mill, it does not turn into work. That derives from gravity. Water at a height possesses potential energy that becomes work with downhill flow."

Paul Sen (2022) Einstein's Fridge. The science of fire, ice and the universe. William Collins.

[Note that energy cannot be created nor destroyed (the principle of conservation of energy) so the idea that energy was created in a mill is an alternative conception.]

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there is an exchange rate between work and heat

An example of an analogy use in popular science writing:

"To Joule, work and heat had become incontrovertible, the one into the the other much like the dollar and the pound. They are both forms of money, and if one knows the exchange rate, one knows how many dollars are equivalent to one pound. Joule believed there was an exchange rate between work and heat. Naming this 'the Mechanical Equivalent of Heat' he set out to discover its value."

Paul Sen (2022) Einstein's Fridge. The science of fire, ice and the universe. William Collins.

This extract can also be seen as including a tautology: "if one knows the exchange rate, one knows how many dollars are equivalent to one pound". That ('how many dollars are equivalent to one pound') is in effect the definition of the exchange rate.

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nerves are to wires as blood vessels are to pipes

An analogy used by a scientist:

"Just as we do not need to distinguish, in principle, between the current in a water pipe and the flow of blood in the vessels, no more should we expect, beforehand, any profound fundamental difference between the propagation of sense impressions in the nerves and conduction of electricity in a metal wire."

Bohr, Neils (1934) Atomic theory and the description of nature. Cambridge University Press

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matter waves leak from the atomic nucleus

An example of metaphor used in a scientist's writing:

"On the other hand, the ordinary mechanical conceptions completely fail to provide us with a description of the course of the disintegration process [of the nucleus], since the field of force surrounding the atomic nucleus would, according to these ideas, prevent the particles from escaping the nucleus. On the quantum mechanics, however, the state of affairs is quite different. Though the field of force is still a hindrance which, for the most part, holds the matter waves back, yet it permits a small fraction of them to leak through. The part of the waves which escapes in this way in a certain time gives us a measure of the probability that the disruption of the atomic nucleus takes place during this time."

Bohr, Neils (1934) Atomic theory and the description of nature. Cambridge University Press

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building stones of atoms were discovered

An example of metaphor in the writing of scientists:

"…despite the great success attending the discovery of the building stones of atoms – a discovery depending on the application of classical concepts – the development of the atomic theory has, nevertheless, first of all given us a recognition of laws which cannot be included within the frame formed by our accustomed modes of perception."

"Negatively charged particles, the so-called electrons, which are held within the atom by the attraction of a much heavier positively charged atomic nucleus, enter as common building stones in all atoms."

Bohr, Neils (1934) Atomic theory and the description of nature. Cambridge University Press

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QBism is to science as Cubism was to art

An example of an analogy used to discucss science:

"But QBism ['Quantum Bayesianism'] is a way of thinking about science quite generally, not just quantum physics, and it is pertinent even when probabilistic judgements, and therefore 'Bayesianism', play no role at all. I nevertheless retain the term 'QBism', both to acknowledge the history behind it, and because a secondary meaning remains apt in the broader context: QBism is as big a break with twentieth-century ways of thinking about science as Cubism was with nineteenth-century ways of thinking about art."

Mermin, N. David (2017) Why QBism is not the Copenhagen interpretation and what John Bell might have thought of it, in, Neils Bohr and the Philosophy of Physics. Twenty-first-century perspectives (Jan Faye & Henry J. Folse, eds.) Bloomsbury Academic: London, pp.367-377.

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split between classical and quantum is shifty

An example of a metaphor used is discussing science:

"…a quantum-mechanical description is always relative to the particular user of of quantum mechanics who provides that description. Replacing that user with an apparatus introduces the notoriously ill-defined 'shifty split' of the world into quantum and classical, that John Bell so elegantly and correctly deplored.

Bell's split is shifty in two respects. Its character is not fixed. It can be the Landau-Lifshitz split between 'classical' and 'quantum'. But sometimes it is a split between 'macroscopic and microscopic'. Or between 'irreversible' and 'reversible'. The split is also shifty because its location can freely be moved along the path between whatever poles have been used to characterise it."

Mermin, N. David (2017) Why QBism is not the Copenhagen interpretation and what John Bell might have thought of it, in, Neils Bohr and the Philosophy of Physics. Twenty-first-century perspectives (Jan Faye & Henry J. Folse, eds.) Bloomsbury Academic: London, pp.367-377.

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Bell's split is shifty

An example of a metaphor used is discussing science:

"…a quantum-mechanical description is always relative to the particular user of of quantum mechanics who provides that description. Replacing that user with an apparatus introduces the notoriously ill-defined 'shifty split' of the world into quantum and classical, that John Bell so elegantly and correctly deplored.

Bell's split is shifty in two respects. Its character is not fixed. It can be the Landau-Lifshitz split between 'classical' and 'quantum'. But sometimes it is a split between 'macroscopic and microscopic'. Or between 'irreversible' and 'reversible'. The split is also shifty because its location can freely be moved along the path between whatever poles have been used to characterise it."

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