Editing 2501: Average Familiarity

{{comic
| number    = 2501
| date      = August 11, 2021
| title     = Average Familiarity
| image     = average familiarity.png
| titletext =  "How could anyone consider themselves a well-rounded adult without a basic understanding of silicate geochemistry? Silicates are everywhere! It's hard to throw a rock without throwing one!"
}}

==Explanation==
This comic claims that experts vastly overestimate how familiar other people are with their own field of study. As an example, [[Randall]] shows a conversation between [[Ponytail]] and [[Cueball]] as two {{w|geochemistry|geochemists}} specializing in {{w|silicate}} chemistry. Although the two scientists understand that the layman does not know all that they know about silicates, they are still under the impression that other people at least know the chemical makeup of {{w|olivine}} and some {{w|feldspar}}s. Cueball also mentions {{w|quartz}}, an even simpler mineral taken for granted by Ponytail. 

In truth, the average person can't be expected to know the chemical makeup of ''any'' arbitrarily-chosen substance reliably (or any material at all), if that average person's job and hobby do not involve chemistry — aside from the few that made their way into {{w|common knowledge}}, like NaCl for salt (sodium chloride or {{w|halite}} in mineral form), H<sub>2</sub>O for water (facetiously known as dihydrogen monoxide, {{w|ice}} in mineral form), or CO<sub>2</sub> for carbon dioxide (while most people are more familiar with its gaseous form, it is also used in mineral form as {{w|dry ice}}), and may not even know the definition of "feldspar" beyond "a mineral", if at all.

It even goes so far as to initially gloss over the 'everyday' knowledge of quartz... until prompted by the slightly-less-overestimating partner in the conversation. Perhaps like a gardener forgetting to mention the lawn he maintains (along with the 'actual' plants in the borders or vegetable patches), there seemed no need to include such a common mineral as a subject of silicate chemistry. Quartz is a basic silicon oxide (SiO<sub>2</sub>) that many non-chemists ''have'' heard of because it is common and has a variety of uses, though they would not know its chemical structure. Quartz ''can'' be found as distinct large-scale crystals (probably obvious to the layman, as an ice-cube is in a drink) but also features as a hard-wearing micro-constituent of many rocks. At a certain high level of weathering - hazily defined as between gravels and silts - sand is overwhelmingly the ultimate residual silicon-dioxide grains in most cases (the main exception to this being coral sands, which are calcium carbonates) though with varying internal linkages as SiO<sub>4</sub> 'units' (sharing oxygen atoms) and other residual constituents dictating the general colour, feel and other physical qualities as you enjoy your day at the beach. Quartz crystals are made into jewelry and other decorative objects. Most modern clocks use the resonance frequency of quartz to keep time.

Minerals like feldspars and olivine generally exist as a continuum of varying chemical formulas, represented as a mixture of "endmembers" that have some pure composition. Feldspars are a category of aluminum-containing silicate minerals that account for the most of the rock in the earth's crust by mass. They are composed of a silicon-aluminum-oxygen lattice filled with sodium, potassium, or calcium ions. The major varieties are CaAl<sub>2</sub>Si<sub>2</sub>O<sub>8</sub> (anorthite), NaAlSi<sub>3</sub>O<sub>8</sub> (albite), and KAlSi<sub>3</sub>O<sub>8</sub> (potassium feldspar). Olivine is most notable as being the primary constituent of the upper mantle and commonly found in stony meteorites, and has the formula X<sup>2+</sup><sub>2</sub>SiO<sub>4</sub>, where X is any iron or magnesium ion. The ends of the spectrum are Mg<sub>2</sub>SiO<sub>4</sub> ({{w|forsterite}}) and Fe<sub>2</sub>SiO<sub>4</sub> ({{w|fayalite}}).

In the title text the two geologists express belief that the average person ''should'' be more familiar with silicates because of how ubiquitous they are. Their somewhat-exasperated statement plays on the phrase "you can't throw a rock without hitting one," a standard hyperbole about how common something is. Indeed, {{w|Silicate mineral|silicate}} rocks are extremely common on Earth &mdash; not only would a rock thrown in a random direction stand a decent chance of striking a silicate mineral rock, but the rock being ''thrown'' also has a very high chance of being a silicate mineral rock. With the exception of a few carbonate deposits, rocks found in large deposits on Earth's surface nearly all have silica in them, even extraterrestrial rocks. The Earth's crust is about 60% silica by weight.<ref>"Constraining crustal silica on ancient Earth" C. Brenhin Keller, T. Mark Harrison. ''Proceedings of the National Academy of Sciences'' Sep 2020, 117 (35) 21101-21107; DOI: 10.1073/pnas.2009431117</ref>

==Transcript==
:[Ponytail and Cueball are talking. Ponytail has her hand raised, palm up, towards Cueball.]
:Ponytail: Silicate chemistry is second nature to us geochemists, so it's easy to forget that the average person probably only knows the formulas for olivine and one or two feldspars.
:Cueball: And quartz, of course.
:Ponytail: Of course.

:[Caption below the panel]
:Even when they're trying to compensate for it, experts in anything wildly overestimate the average person's familiarity with their field.

== References ==
<references />

{{comic discussion}}

[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Cueball]]
[[Category:Geology]]
[[Category:Science]]