Making the unfamiliar familiar – with everyday spheres
Keith S. Taber
Even scientists reporting their work in top research journals are not above using comparisons with everyday analogues to explain their ideas.
An analogue for a molecular structure?
(Image by Eduardo Ponce de Leon from Pixabay)
One of the phrases I return to a good deal on these pages is 'making the unfamiliar familiar' because a large part of science teaching is indeed about introducing scientific concepts that are currently unfamiliar to learners (oxidising agents, the endoplasmic reticulum, moments of inertia…the list is extensive!), so they become familiar to learners.
So, teachers use analogies, metaphors, narratives, images, models, and so forth, to help link something new (and often abstract) to whatever 'interpretive resources' the teacher thinks the learners have available to make sense of what is still novel to them.
Read about key ideas for constructivist teaching
This process can certainly go wrong – learners can confuse what is meant as a kind of stepping stone towards a scientific concept (e.g., a teaching analogy, or a simplified model) for the concept itself. So, as just one example, dot and cross figures showing electron transfer between atoms that are sometimes employed to help introduce the idea of ionic bonding come to be confused with ionic bonding itself – so that learners come to wrongly assume electron transfer is a necessary part of ionic bond formation – or, worse, that ionic bonding is electron transfer (e.g., Taber, 1994).
The familiarisation devices used in teaching, then, could be seen as a kind of 'dumbing down' as they work with the familiar and concrete or easily visualised or represented, and fall short of the scientific account. Yet, this approach may be necessary to produce meaningful learning (rather than rote learning that is not understood, and is soon forgotten or becomes confused).
Scientists need to make the unfamiliar familiar
So, it is worth pointing out that scientists themselves, not just science teachers and journalists, often appreciate the need to introduce new ideas in terms their readers can imagine and make sense of. I have noted lots of examples from such contexts on this site. 1 Now this happens a lot in 'popular' science communication, when a scientist is writing for a general audience or being interviewed by a journalist.
Read about science in public discourse and the media
But it also happens when scientists are primarily addressing their peers in the scientific research community. One of my favourite examples is the liquid drop model of the nucleus.
The atomic nucleus is like a drop of liquid because…
Lise Meitner had been working with Otto Hahn and Fritz Strassmann in the Kaiser Wilhelm Gesellschaft in Berlin, Germany, where they were investigating properties of radioactive elements. It was known some heavy elements would decay through processes such as alpha decay, which leads to an element with an atomic number two less than the starting material. 2 Their laboratory results, however, suggested that bombarding uranium with neutrons would directly lead to elements much less massive than the uranium.
By the time these results were available, Meitner had left Germany for her own safety. She would have been subject to persecution by the Nazis – quite likely she would have been removed from her scientific work, and then later sent to one of the concentration camps before being murdered as part of the genocide carried out against people the Nazis identified as Jews. 3
Hahn and Strassmann sent Meitner their findings – which did not make sense in terms of the nuclear processes known at the time. With her nephew, Otto Robert Frisch, Meitner decided the results provided evidence of a new phenomenon based on a previously unexpected mechanism of nuclear decay – fission. Nuclear fission was the splitting of a heavy nucleus into two smaller nuclei of roughly similar mass (where alpha decay produced a daughter nearly as heavy along with the very light helium nucleus).
Meitner and Frisch explained this by suggesting a new model or analogy for the nucleus:
"On account of their close packing and strong energy exchange, the particles in a heavy nucleus would be expected to move in a collective way which has some resemblance to the movement of a liquid drop. If the movement is made sufficiently violent by adding energy, such a drop may divide itself into two smaller drops."
Meitner & Frisch, 1939
This was published in the top scientific journal, Nature – but this was no barrier to the scientists using an everyday, familiar, analogy to explain their ideas.
(Image by Gerhard Bögner from Pixabay)
Chemistry and the beautiful game?
A much later example appeared in the same journal when Kroto and colleagues published their paper about the newly reported allotrope of carbon (alongside graphite and diamond) with formula C60 by including a photograph in their article. A photograph of…an ordinary football!
They used the football to explain the suggested molecular geometry of C60, which they referred to as buckinsterfullerene,
"Concerning the question of what kind of 60-carbon atom structure might give rise to a superstable species, we suggest a truncated icosahedron, a polygon with 60 vertices and 32 faces, 12 of which are pentagonal and 20 hexagonal. This object is commonly encountered as the football shown in Fig. 1."
Kroto, et al., 1985
A football (notice the panels are hexagons and pentagons 4). (Image by NoName_13 from Pixabay)
Kroto and colleagues submitted a photograph like this to be published as a figure in their scientific report of the discovery of the buckminsterfullerene allotrope of carbon
What could be more familiar to people than the kind of ball used in Association Football ('soccer')? (Even if this is not really a truncated icosahedron 4). Their figure 1 showed,
"A football (in the United States, a soccerball) on Texas grass. The C60 molecule featured in this letter is suggested to have the truncated icosahedral structure formed by replacing each vertex on the seams of such a ball by a carbon atom."
Kroto, et al., 1985
The scientists explained they had come across the suggested shape when searching for a viable molecular structure that fitted the formula (sixty carbon atoms and nothing else) and which would also satisfy the need for carbon to be tetravalent. They investigated the works of the designer/architect Richard Buckminster Fuller, famous for his geodesic domes.
A stamp commemorating the life and works of Richard Buckminster Fuller and representing geodesic domes.
Thus they provisionally called the new substance buckinsterfullerene, albeit they acknowledged this name might be something of a 'mouthful', so to speak,
"We are disturbed at the number of letters and syllables in the rather fanciful but highly appropriate name we have chosen in the title [of their paper] to refer to this C60 species. For such a unique and centrally important molecular structure, a more concise name would be useful. A number of alternatives come to mind (for example, ballene, spherene, soccerene, carbosoccer), but we prefer to let this issue of nomenclature be settled by consensus."
Kroto, et al., 1985
We now know that the term 'buckyballs' has become popular, but only as a shorthand for the mooted name: buckinsterfullerene. (Later other allotropic form of carbon based on closed shell structures were discovered – e.g., C70. The shorter term fullerenes refers to this group of allotropes: buckminsterfullerene is one of the fullerenes.)
I recall seeing a recording of an interview with Harry Kroto where he suggested that the identification of the structure with the shape of a football came during a transatlantic phone call. What I would love to know is whether Kroto and his co-authors were being somewhat mischievous when they decided to illustrate the idea by asking the world's most famous science journal to publish a figure that was not some abstract scientific representation, but just a photograph of a football. Whether or not they were expecting kick-back [sorry] from the journal's peer reviewers and editor, it did not act as an impediment to Curl, Kroto and Smalley being awarded the 1996 Nobel prize for chemistry "for their discovery of fullerenes" (https://www.nobelprize.org/prizes/chemistry/1996/summary/).
Work cited:
- Kroto, H., Heath, J., O'Brien, S., Curl, R. F. & Smalley, R. E. (1985) C60: Buckminsterfullerene. Nature, 318, 162-163. https://doi.org/10.1038/318162a0
- Meitner, L., Frisch, O.R. (1939) Disintegration of Uranium by Neutrons: a New Type of Nuclear Reaction. Nature, 143, 239-240. https://doi.org/10.1038/143239a0
- Taber, K. S. (1994) Misunderstanding the ionic bond, Education in Chemistry, 31 (4), pp.100-103.
Notes:
1 There is a range of tactics that can be used to help communicate science. Generally, to the extent these make abstract ideas accessible, they are presentations that fall short of the scientific account – and so they are best seen as transitional devices to offer intermediate understandings that will be further developed.
I have included on the site a range of examples I have come across of some of the ways in which science is taught and communicated through analogies, metaphors and so forth. Anthropomorphism is when non-human objects are discussed as if having human feelings intentions and so forth.
Read about anthropomorphism in science discourse
2 The radioactive decay of unstable but naturally occurring uranium and thorium takes place by a series of nuclear processes, each producing another radioactive species, till a final step produces an isotope which can be considered stable – 206Pb (from decay of 238U), 207Pb (from decay of 235U) or 208Pb (from decay of 232Th). By a pure coincidence of language (a homograph), in English, these radioactive decay cascades lead to lead (Pb).
3 That is not to say most of those murdered because they were Jewish would not have self-identified as such, but rather that the Third Reich had its own racist criteria (established by law in 1935) for deciding who should be considered a Jew based on unscientific notions of bloodlines – so, for example, being a committed and practising Christian was no protection if the Nazis decided you were from a Jewish family.
(Nazi thinking also drew on a very influential but dangerous medical analogy of the volk (people) as a body that allowed those not considered to belong to the body to be seen as akin to foreign microbes that could cause disease unless eliminated.)
4 Of course a football is not a truncated icosahedron – it is intended to be, as far as possible, spherical! The pentagons and hexagons are made of a flexible material, and within them is a 'bladder' (nowadays this is just a metaphor!) which is an elastic sphere that when inflated presses against the outer layers.
If a football was built using completely rigid panels, then it would be a truncated icosahedron. However, such a 'ball' would not roll very well, and would likely cause some nasty head injuries. Presumably the authors were well aware of this, and assumed their readers would see past the problem with this example and spontaneously think of some kind of idealised, if far from ideal, football.