Comparisons – Page 25 – Science-Education-Research

distillation separates spirit from phlegm

An example of a term used by analogy,

"In the early 19th century, many formerly artisinal processes were scaled up and intensified as part of the Industrial Revolution. Distillation was well-established as a technique, and production of various kinds of hooch was growing steadily. This involved heating a fermented mash at the bottom of a pot still to separate the more volatile 'spirit' from the heavier aqueous 'phlegm'."

Sella, Andrea (2023), Sorel's plates, Chemistry World, 20 (5), https://www.chemistryworld.com/opinion/sorels-plates/4017311.article

In alchemy the phlegm was the residue after a separation process such as distillation. In ancient Greek medicine, phlegm was one of the four bodily humours (that needed to be in balance for good health). A key feature of traditional thinking (for example, influencing alchemy) was the notion of correspondences in nature – that the body reflected the wider cosmos, as there were correspondences between earth and the heavens.

The term 'spirits' for distilled alcoholic drinks is still in use today.

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battery recycling is like trying to reclaim jam and cream from a Victoria sponge after shredding

An example of an analogy used to explain in science:

"Traditionally, battery recycling is not particularly sophisticated, chemically speaking, [Emma Kendrick, a battery researcher at the University of Birmingham, UK] explains. 'Often you stick it in the shredder, and then you try and sort it out later.' …

'There's a need for redesign, to start thinking about what happens to these batteries at the end of life and how we can more easily disassemble them and reclaim pure material waste streams,' says Kendrick. 'Because right now, we put all this effort into creating highly engineered cells and then stick them in a shredder.' …

Kendrick said battery recycling now is 'a bit like making a Victoria sponge cake, then sticking the entire thing through a shredder and hoping to reclaim the jam and cream'."

Professor Emma Kendrick, School of Metallurgy and Materials, University of Birmingham, was being quoted in,

Anthony King (2023) Battery recyclers race to increase capacity and efficiency, Chemistry World, 20 (5), https://www.chemistryworld.com/news/battery-recyclers-race-to-increase-capacity-and-efficiency/4017302.article

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pools of dissolved lithium salts are like a disturbed artist's palette

An example of the use of simile in science journalism:

"The world's second-largest supplier of lithium is Chile (39,000 tons a year). Rather than crush rocks, the Chilean mines pump out lithium dissolved in groundwater brine, which is then poured into pools that can evaporate in the hot, dry wastes of the Atacama desert, eventually leaving white, powdery lithium salts. Yet as stunning as these appear – from shades of aquamarine to bright yellow, like a disturbed artist's palette dropped in the otherwise empty expanse of the driest place on Earth – they leave a terrible chemical legacy, including damage to fresh water supplies for local communities and disruption to wildlife habitat."

Kit Chpman (2023) The lithium rush, Chemistry World, 20 (5), https://www.chemistryworld.com/features/the-lithium-rush/4017304.article

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alchemist without the damned earth is like a sailor without his ship

An example of analogy, and metaphor, used in explaining a proto-scientific idea:

"The damned earth…is the mighty 'instrument' that opens the gates of matter, allowing the innermost parts of bodies to be revealed and intimately examined. Like a sailor who cannot acquire knowledge of other peoples without his ship, 'so [according to alchemist Edward Kelley] the philosopher, unless he has this damned earth, will perceive little or nothing of the most important secrets in other metals'. This chemical instrument is evidently a solvent capable of dissolving precious metals…' The Damned Earth alone is the doorkeeper, the only master, which can open up these mysteries of nature."

Jennifer M. Rampling (2020) The Experimental Fire. Inventing English Alchemy, 1300-1700. The University of Chicago Press.

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each metal corresponds to a different planet

An example of analogical thinking in proto-science,

"…[alchemist Edward] Kelley explains the nature of the imperfect metal in his fullest elaboration of sericonian doctrine, as a work based on Saturn, or lead. The power of lead is introduced using an analogy between the metals and the orbits of their corresponding planets; thus the work begins with Saturn because this is also the outermost planet, 'within whose [sic] circle the spheres of the others are naturally encompassed'. Just as the orbit of Saturn must contain those of the inner planets, so the metalline water drawn from Saturn's metallic analogue, lead, must include the properties of the other metals. It follows that lead is the only metal whose menstruum will dissolve the rest.

Both Kelley's orbital analogy and the theory of metals that underpins it are grounded in late medieval sources that present alchemy as a 'lower astronomy' (astronomia inferior), in which the seven metals map onto the seven Ptolemaic planets."

Jennifer M. Rampling (2020) The Experimental Fire. Inventing English Alchemy, 1300-1700. The University of Chicago Press.

Traditionally the correspondences are:

lead – Saturn
tin – Jupiter
iron – Mars
copper – Venus
quicksilver – Mercury
silver – Moon
gold – Sun

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This extract also reflects the common personification of the planets (i.e., 'whose' to refer to Saturn's orbit rather than 'which').

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menstruum nourishes the philosopher's stone

An example of metaphor used in proto-scientific thinking:

"The spirit of wine is called aqua ardens because of its burning virtue, and menstruum because it nourishes the stone just as menstrual blood nourishes an infant within the womb. It is also called coelum, or 'heaven', because it is infused with celestial virtues."

Jennifer M. Rampling (2020) The Experimental Fire. Inventing English Alchemy, 1300-1700. The University of Chicago Press.

Rampling is here commenting on writings of 16th Century alchemist and physician William Blomfild (or Bloomfield).

The term 'mentsruum' was commonly used by alchemists for a solvent used in their laboratory work. Spirit of wine was obtained by distilling wine – to give a concentrated solution of ethanol. Strong alcoholic drinks do indeed 'burn' the tissues when imbibed.

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The comparison with menstrual blood is an analogy

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tail of a comet ascends away from the sun like smoke that ascends in a chimney by the impulses of the air in which it floats

An example of an analogy used to explain a scientific phenomenon:

"Someone else believes that there can be particles with the property of levity as well as gravity and that the matter of the [comet] tails levitates and trough its levitation ascends away from the sun. But…I suspect that that this ascent arises rather from the rarefaction of the matter of the tails. Smoke ascends in a chimney by the impulses of the air in which it floats. This air rarefied by heat, ascends because of its diminished specific gravity and carries along with it the entangled smoke. Why should the tail of a comet not ascend away from the sun in the same manner?"
Isaac Newton

Isaac Newton (1999) Mathematical Principles of Natural Philosophy (3rd edition, 1726): The authoritative translation (I. Bernard Cohen and Anne Whitman), University of California Press

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The idea (that Newton ascribes to an unnamed other) that some materials might exert a property of levity (a tendency to ascend), as an inherent quality distinct from gravity, was once quite common.

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Parker Solar Probe speed like flying from London to New York in less than 30 seconds

An example of an everyday comparison used to explain an extreme scientific fact:

"The Parker Solar Probe is plunging into our star's outer atmosphere, enduring brutal temperatures and extreme radiation…

The probe will have to endure temperatures of 1,400C and radiation that could frazzle the onboard electronics. It is protected by a 11.5cm (4.5 inches) thick carbon-composite shield but the spacecraft's tactic is to get in and out fast. In fact, it will be moving faster than any human-made object, hurtling at 430,000mph – the equivalent of flying from London to New York in less than 30 seconds."

Rebecca Morelle & Alison Francis (2024, 24th December), Spacecraft attempts closest-ever approach to Sun, BBC News on-line article

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sulphur nanoparticles are bound in the cathode in a sort of spiderweb network

An example of simile used to explain a scientific idea:

"An additional complication with lithium sulphur batteries is that, when the sulphur absorbs lithium during battery discharge, it swells by about 80%. A slab of sulphur would disintegrate after a few cycles; a more elastic material is required. 'We have developed a sort of spiderweb network where we use flexible binders to hold nanoparticles of sulphur together, and then the cathode could swell up and contract without falling apart,' Hill says."

Prof. Matthew Hill, Head of Department of Materials Science and Engineering at Monash University, Australia

was quoted in James Mitchell Crow (2023) Building better batteries, Chemistry World, 20 (5), https://www.chemistryworld.com/features/building-better-batteries/4017313.article

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lithium ions nestle in a happy house built of graphite

An example of the use of metaphor in reporting science:

'In terms of whether there are brand new chemistries that can have the energy density competitive with lithium, at this moment the short answer is no,' argues Ping Liu, a battery researcher at the, US. But that's not to say we couldn't make lithium-based batteries with many times the energy density of today's commercial batteries, he adds.

…Commercial lithium-ion batteries invariably use graphite as an intercalation anode. The lithium ions nestle between individual layers of the graphite host. 'With graphite you build a happy house for lithium,' Liu says. But the graphite adds bulk and weight to the battery, lowering its energy density.

…In Liu's lab, his recent work has focused on the surface that the lithium plates onto. Lithium plating involves two interfaces: the anode surface and the electrolyte. Lithium's high reactivity means the anode is always coated with a passivation layer called the solid electrolyte interface (SEI), produced by electrolyte decomposition…For efficient battery charging, an SEI rich in lithium fluoride has been shown to be beneficial. 'That has been a magical compound,' Liu says. 'People say it is because lithium has very weak interaction with lithium fluoride, so the passivation layer doesn't slow it down.'…Having the incoming lithium ions able to skate about on the surface might be a better route to a smooth, flat lithium surface, Liu suspected. 'If lithium fluoride is such a magic compound, why don't we also have it on the substrate side?' he wondered. His team created a lithium fluoride surface studded with conductive iron fluoride islands as lithium nucleation sites. 'Once lithium nucleates on iron, its surface diffusion is very rapid and we got these beautiful crystals. So the whole idea that lithium fluoride is magical is true.' The team now aims to incorporate the concept into a practical battery.

…In the commercial lithium-ion battery, electrode compromises continue at the cathode side of the cell. Again, a nice, layered home is provided for lithium ions to nestle into as the battery is discharged, in the form of a nickel cobalt manganese oxide material. But the metal oxide material adds a certain weight, as well as cost. "

James Mitchell Crow (2023) Building better batteries, Chemistry World, 20 (5), https://www.chemistryworld.com/features/building-better-batteries/4017313.article

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explaining celestial motion with vortices is like explaining the mechanism of a clock before inspecting it

An historical example of an analogical argument in science:

"In mechanical clocks one and the same motion of the hour hand can arise from the action of a suspended weight or an internal spring. But if the clock under discussion is really activated by a weight, then anyone will be laughed at if he imagines a spring and on such a premature hypothesis undertakes to explain the motion of the hour hand; for he ought to have examined the internal workings of the machine more thoroughly, in order to ascertain the true principle of the motion in question. The same judgement or something like it should be passed on those philosophers who have held that the heavens are filled with a certain most subtle matter, which is endlessly moved in vortices. For even if these philosophers could account for the phenomena with the greatest exactness on the basis of their hypotheses, still they cannot be said to have given us a true philosophy and to have found the true causes of the celestial motions until they have demonstrated either that these causes really do exist or at least that others do not exist. Therefore if it can be shown that the attraction of all bodies universally has a true place in the nature of things, and if it can further be shown how all the celestial motions are solved by that attraction, then it would be an empty and ridiculous objection if anyone said that those motions should be explained by vortices, even if we gave our fullest assent to the possibility of such an explanation."

Roger Cotes (1713), Plumian Professor of Astronomy and Experimental Philosophy at Trinity College Cambridge, Editor's preface to the second edition of Newton's Principia.

In, Isaac Newton (1999) Mathematical Principles of Natural Philosophy (3rd edition, 1726): The authoritative translation (I. Bernard Cohen and Anne Whitman), University of California Press

(The notion of the 'heavens [being] filled with a certain most subtle matter, which is endlessly moved in vortices' reads as a rather poor straw man target today, but was seriously proposed by Descartes.)

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anthropological insight is ethnographer's magic

An example of a simile used in writing about research:

"Anthropology, after Malinowski, was presented as a scientific exercise, but it was essentially an interpretive subject. It required an ability to see through everyday activities and reveal their deeper meaning: this was the 'ethnographers's magic', a kind of academic insight that could seem hopelessly elusive when your greatest challenge was to follow basic conversations in an unfamiliar language."

Frances Larson (2021) Undreamed Shores. The hidden heroines of British anthropology. London: Granta

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