Category: STEM Education Poetry

“Assembling set-up, distillation,
Can lead to a bit of frustration.
Be sure to securely 
Clamp glassware so surely
Experiment defies ruination!”  

The 9 April 2021 Twitter limerick highlighted distillation, a lab technique used in organic chemistry laboratories to purify liquid samples.  The poem highlights one of the ways in which such a lab technique might go awry… and encourages students to avoid it!  

“Assembling set-up, distillation, /
Can lead to a bit of frustration…” 

The first semester of organic chemistry lab introduces techniques and tools one at a time, building to increasingly complex experiments in which their uses can be combined.  One such technique is distillation: separating a liquid mixture into its component parts, based on differences in their boiling points.

A “simple distillation” is typically one wherein two components of a liquid mixture have boiling points distinct from one another.  This mixture is placed in a round-bottomed flask, which is connected to a condenser, which is connected to a receiving flask.   The mixture is heated until it reaches the boiling point of the first component; at this point, the first component vaporizes, travels as a gas into the condenser, and is condensed into the first receiving flask.  (The condenser circulates cooling water through an outer jacket: within the complex set-up of the laboratory fume hood, one condenser tube connects to a faucet and the other to a drain.)  Once this first component is separated out, a second receiving flask is used to collect the second component, as its own boiling point is reached.    

Typically, these steps are all new for students; although they will become well-practiced with the distillation set-up, assembling it can be frustrating initially.   

“Be sure to securely /
Clamp glassware so surely /
Experiment defies ruination!”  

This set-up is often one of the first to involve multiple pieces of glassware– including, most notably, the condenser. To avoid “ruination” (the watery collapse of the endeavor!), it is important to clamp the pieces of glassware together and, further, to clamp everything securely within the hood itself. 

“Exacting; extracting… 
A sep funnel’s function:
To isolate layers and
Compound obtain.
(Avoid a moment most 
Melodramatical:
Ere product’s sure, 
From waste’s discard, 
Refrain!)”

The 8 April 2021 Twitter poem addressed another laboratory technique: using a separatory funnel, a specialized piece of glassware that allows a chemist to separate different components of a given reaction mixture (the environment in which the reaction has been taking place).  

“Exacting; extracting… /
A sep funnel’s function: /
To isolate layers and /
Compound obtain.”

Each step of an organic synthesis depends on two key parts: the reaction itself, which converts reactant to product, and the work-up, in which the product compound is isolated (identified and purified), while excess solvents and side materials are discarded.  

The separatory funnel (“sep funnel”), as its name suggests, is particularly useful in separating liquid layers from one another, based on their different densities.  Often, the layers of interest are “water” versus “non-halogenated organic solvents,” where the latter layer would be less dense than the former.  In the case of “water” versus “halogenated organic solvents,” through, the latter layer is more dense than the former.  (Chemists typically use “aqueous” and “organic” as efficient shorthand for the layers.)

Either way, depending on which layer the target product occupies, the chemist will use the sep funnel, to “compound obtain.”  

“(Avoid a moment most /
Melodramatical: /
Ere product’s sure, /
From waste’s discard, /
Refrain!)”

I suspect that anyone reading the discussion of different densities above, whether or not they are a chemist, might quickly note the most challenging hazard of using a sep funnel: being absolutely sure which layer is which (and which layer thus contains the product) before proceeding.  A best practice is to wait to discard the other layer until subsequent steps are completed, to be sure the target product hasn’t been accidentally lost: “Ere product’s sure, / From waste’s discard, / Refrain!”

When a student is learning the technique, though, this lesson can sometimes be hard-won.  This is unfortunately clear from the occasional “moment most / [m]elodramatical”… directly after the moment when someone’s synthesized product is inadvertently lost to the waste container.

“Consider lab drawer’s Bunsen burner…
Providing new role for chem learner
(Through method, flame-testing,
Steps towards metal-guessing):
Of cation’s ID, discerner.”  

The 7 April 2021 limerick summarized a qualitative analysis technique often used in introductory chemistry, which employs one of its most memorably named instruments, the Bunsen burner.  

“Consider lab drawer’s Bunsen burner… /
Providing new role for chem learner…”

Combustion can occur completely or incompletely.  Complete (stoichiometric) combustion is what is taught in the textbooks: a hydrocarbon fuel reacts with oxygen and is converted fully to carbon dioxide and water.  The path from start to finish actually occurs via a wide network of complex reactions involving radicals, which are species with unpaired electrons; these can cause all sorts of side reactions and products.  When the combustion is incomplete, these side reactions include the formation of soot.  Soot has many detrimental effects, and Robert Bunsen (1811-1899) was interested in developing a burner that could produce a particularly clean flame, avoiding these effects.  His burner has been widely adopted for use in introductory chemistry laboratories (by “chem learner[s]”).     

“(Through method, flame-testing, /
Steps towards metal-guessing): /
Of cation’s ID, discerner.”

A traditional and interesting use of the Bunsen burner is the flame test, or “method, flame-testing.”  A wire is placed into a solution made from an ionic compound, which includes a cation derived from a metal of interest.  The wire is then placed into the flame, and as the ionic solution evaporates, the flame will turn a certain color based on the emission characteristics of the metal ion in question.  For instance, copper would turn the flame a bluish-green, and potassium would turn the flame violet.  

If a student is given an unknown compound and asked to determine the cation in this compound, they could use the flame test behavior as a step towards identifying the unknown; their role as “chem learner” could then also include being “of cation’s ID, [a] discerner.”              

“Procedure today: use the crucible!  
Obtain sample’s make-up, deducible
Through tasks gravimetric 
And steps arithmetic;
Key data emerge, thus computable.”  

The 6 April 2021 limerick addressed another common laboratory technique: the use of a crucible, which can have applications both qualitative and quantitative in the chemistry lab.  

“Procedure today: use the crucible!”  

Crucibles are containers that can be heated to very high temperatures; as such, they are useful in a wide variety of chemistry settings.  In introductory chemistry, they typically inform some of the most interesting questions during lab check-in, as they aren’t as familiar and/or repetitive as some of the other materials in a lab drawer, such as flasks, beakers, or graduated cylinders.  

While the composition of crucibles can vary in industry and other settings, in the intro lab, crucibles are typically small ceramic dishes.  The main idea is that, when a crucible containing a sample of interest is heated, the sample will be affected by the heat (decomposing or otherwise reacting), while the crucible itself will be unaltered.  (In popular culture, the name is likely most familiar from Arthur Miller’s 1953 dramatic work, giving this essay its title.)  

“Obtain sample’s make-up, deducible /
Through tasks gravimetric /
And steps arithmetic; /
Key data emerge, thus computable.”  

One common use of the crucible is in a technique called gravimetric analysis.  By heating a reaction product to high temperatures in a crucible, it is possible to fully dry the product and obtain its exact mass (“tasks gravimetric”).  Through the use of that exact mass and the principles of reaction stoichiometry (“steps arithmetic”), a chemist can also determine the percent composition of a component ion, or analyte, in the pertinent starting material: “the sample’s make-up [is] deducible.”  

While this limerick emerged out of contemplating some rhymes (one more accurate than the other!) for “crucible,” it was a fun challenge to align the poem structure with a reasonable summary of the experiment. 

“With cylinder’s use (graduated),
A volume can be calculated…
Keep eye on meniscus;
Report results; discuss
The findings from lab extricated.”

This Twitter limerick was posted on 5 April 2021.  It (and, indeed, the next few as well) will pose some interesting challenges!  During this “week” of poems from April 2021, my goal was to take introductory chemistry lab routines and summarize them poetically. While it was fun to turn those everyday tasks into some brief, lyrical descriptions, I am less confident in my ability to expand on them here!  However, as I saw with this post, I still have much to learn regarding background information and etymology for even the most typical of lab routines.  

“With cylinder’s use (graduated), /
A volume can be calculated…”

A graduated cylinder is a common tool in an introductory chemistry student’s lab drawer. As the name suggests, this piece of glassware is cylindrical in shape, and the “graduations” marked on it are indicators of the volumes that can easily be measured with that specific cylinder.  Typically, a student’s lab drawer will contain several of these cylinders, spanning a range of possible volumes to be measured.

“Keep eye on meniscus; /
Report results; discuss /
The findings from lab extricated.”

These last three lines sum up the purpose of using a graduated cylinder: measuring a given volume. To do this, a student carefully examines the reading in a graduated cylinder, looking for where the meniscus, the curve created by the liquid in the cylinder, hits the pertinent line on the side of the cylinder.  

(It is always intriguing in writing even these brief essays to come back to the etymologies of some of these terms.  Meniscus is from the Greek for “crescent,” the descriptiveness of which word presumably accounts for its varied presence in multiple disciplinary settings.)

This poem grew out of some idle pondering of a rhyme for an unusual chemistry term, as many of these do.  To make “discuss” plausible as a rhyme for the final two syllables of “meniscus,” this poem describes a common goal in a lab setting. In reporting on the volume measured for a given liquid, a student would “discuss / [t]he findings from lab extricated”: the data they obtained in lab by using their graduated cylinder to complete the week’s procedure.

“3-D geometry:
V S E P R, the
Theory confusing can
Seem when first faced;
So many vocab terms,
Matter-of-factual.
Summed up: electron pairs
Want their own space.” 

The 2 April 2021 Twitter poem approaches the form of a double dactyl.  It introduces a common theory used in introductory chemistry coursework: valence-shell electron-pair repulsion theory, or VSEPR Theory.       

“3-D geometry: /
V S E P R…”

One major theme of a first-year chemistry course is molecular geometry: the shape a molecule takes.  One explanation for this shape is VSEPR Theory; the acronym stands for “valence-shell electron-pair repulsion.”  For this poem’s meter, the letters are pronounced individually; it’s common for a chemistry instructor to alternate between stating the letters and saying the word “vesper.”      

“…the /
Theory confusing can /
Seem when first faced; /
So many vocab terms, /
Matter-of-factual.”

Learning VSEPR Theory can be challenging on multiple fronts.  Not only is the general idea of a molecule’s having a three-dimensional geometry often new to students, depending on what they’ve seen in previous courses, but the specific vocabulary with which VSEPR geometries are described is extensive.  Terms like “see-saw,” “linear,” “T-shaped,” and “bent” (and many others) all have particular denotations in VSEPR theory; further, many overlap with words that already have everyday meanings for students.  (I used “matter-of-factual” in the single-word line here, since chemistry is generally described as the study of matter.)  

“Summed up: electron pairs /
Want their own space.” 

The last two lines here translate VSEPR into everyday language.  Valence electrons are the outermost electrons for a given element, contrasted with the core electrons.  When elements combine to form molecules, these electrons (ultimately present in a molecule as covalent bonds or lone pairs) will repel one another, meaning that the geometry that the resultant molecule adopts will be the one that maximizes distance between these electron pairs, which “want their own space.”  While this phrasing is far less precise than the subsequent vocabulary we will use, deliberately demystifying the acronym is a useful first step in class.     

Fall 2020 winds
Down to a close in
Semester historic with
Finals week near. 
Faculty, students, and
Staff can consider, most
Thankfully, respite from
Challenging year.

The 23 November 2020 Twitter poem highlighted the nearing “finish line” of the autumn semester, commemorated by the week’s Thanksgiving break.  

“Fall 2020 winds /
Down to a close in /
Semester historic with /
Finals week near…”

Autumn 2021 has also been unusual, but there are many welcome returns to routine that I have noted with the passing weeks: classes in person; events on campus.  The 2020 fall semester was truly historic, and it was a relief to near the end of the semester.   

“Faculty, students, and /
Staff can consider, most /
Thankfully, respite from /
Challenging year.”

This will be a short post: not much can be said beyond a statement of gratitude for the immense efforts expended by the entire university community over the past year and a half, aiming for the best possible outcomes in incredibly challenging circumstances.  As always, the Thanksgiving weekend is a good chance to gather energy for the final few weeks of projects and exams in the semester.    

Gaseous chapter frames
Axiomatic’ly
P, V, n, R, T:
Equation “ideal.”
(Think re: gas species’ own
Volumes and actions as
Rule is expanded to
Statement more “real.”)

The 16 November 2020 Twitter poem commemorated a traditionally late-in-semester topic, with a summary of some key equations related to gas chemistry.  

“Gaseous chapter frames /
Axiomatic’ly /
P, V, n, R, T: /
Equation ‘ideal.’”

One of the most useful equations in an introductory chemistry course is the ideal gas law, which combines several principles of gas behavior into an equation, “axiomatic’ly”: PV = nRT.  Here, P represents pressure, V represents volume, n represents amount, R is the gas constant, and T represents temperature.  

The ideal gas law is a flexible formula that has several useful applications for scientists, letting us both see qualitative relationships (e.g., at constant volume and amount, pressure is directly proportional to temperature) and complete a variety of calculations related to these properties.      

“(Think re: gas species’ own /
Volumes and actions as /
Rule is expanded to /
Statement more ‘real.’)”

The ideal gas law is named as such because it idealizes gas behavior, imagining that an atom or molecule of any gas (regardless of chemical identity) will act in the same way as an atom or molecule of any other gas.  Gas particles are envisioned as spheres that undergo efficient collisions at the particulate level, resulting in the big-picture properties modeled by the ideal gas law at the macroscopic level.  The volume of the gas sample is treated as the volume of the gas’s container. 

Scientists have also developed “real” gas laws, which take gas molecules’ own chemical behaviors into account: the volumes that the gas molecules occupy and the intermolecular forces exhibited by each specific molecule.  In other words, they “think re: gas species’ own volumes and actions,” compiling experimental parameters for a variety of gases to more accurately represent behavior in extreme conditions (such as high pressure).  Multiple real gas equations have been devised. 

“Writing a lab report!
Challenging hurdle in
Finishing weekly work:
Goals, findings linked. 
Provide the record most
Quantificational;
Share with the audience:
Summ’ry succinct.”

The 9 November Twitter poem highlights another common writing endeavor from STEM courses: drafting and revising a lab report, after writing up the week’s experiment in the lab notebook.  

“Writing a lab report! /
Challenging hurdle in /
Finishing weekly work: /
Goals, findings linked.”

Laboratory (lab) courses generally require a subsequent write-up of objectives, procedure, and results, after each week’s experiment is completed.  This is a separate writing endeavor from keeping a lab notebook and involves a more formal writing effort.  While report format can vary across scientific fields, the main idea of reporting both “goals [and] findings” is consistent.  

“Provide the record most /
Quantificational…”

In chemistry lab reports, one main aim is contextualizing the data and calculations involved in the experimental procedure.  For a synthetic experiment, what were the masses of the reagents, and what was the ensuing theoretical yield? If the experiment involved a spectroscopic procedure, what were the instrumental settings and the findings of interest?  Are these results on a plausible scale, and can the student show/support the path by which they obtained their findings?  These data and analyses tend primarily to be quantitative, or “quantificational,” in double-dactyl parlance.  

“Share with the audience: /
Summ’ry succinct.”

More generally, other essays in this space have also addressed writing lab reports and scientific papers as key parts of a STEM education.  The skill set of using observational and communication techniques to write an effective explanatory report to a specific audience is one that will undeniably transfer into a wide variety of post-graduate paths.  

However, to return to the “challenging hurdle” characterization in the second line, it is also undeniable that a lab-report-writing effort can be frustrating in the moment, as it requires simultaneously learning and using a challenging disciplinary jargon to succinctly sum up a complicated procedure.