Posts Tagged ‘laboratory instruction’
Chemical Education Roundup, 2-9-13
What’s new in the world of chemical education in 2013? In this edition of the CE Roundup, I’ll engage in a bit of shameless self-promotion, and we’ll look at articles that shed new light on the costs of publishing, innovations in laboratory instruction, student evaluations, and more.
Let’s get the shameless self-promotion out of the way first. Two weeks ago, the Introductory Organic Chemistry MOOC (massive open online course) kicked off on Coursera. The materials for this course were prepared by myself and my colleagues at UIUC for use with our organic chemistry 1 course for non-majors. I’m leading the Intermediate Organic Chemistry (organic chemistry 2) effort, and although that class hasn’t started yet, I’ve been knee deep in the MOOC world for a while now. I’ve got a whole series of blog posts planned on the MOOC experience, so stay tuned!
What is it about the winter months and great literature articles? Perhaps the cold bores people into writing. Who knows? Either way, the literature’s been very interesting in early 2013.
First, teacher reflection and cognition in the classroom. Reflective teachers generally see better student evaluations than unreflective ones. No surprise there: drivers who actually watch the road are better than those who don’t! But how much reflection is enough? A recent study in Brit. J. Educ. Technol. sheds some light on the question. The authors found that formative (weekly) student evaluations increased teachers’ reflective practice, and that increased levels of the latter lead to higher student evaluations over a multi-year period. Some would say that formative student evaluations could promote a “consumer culture” in education, however. There’s an interesting debate brewing there. In a study focused on science teachers, a team of researchers writing in to J. Res. Sci. Teach. found that teachers’ “noticing patterns”—patterns in their attention during class—indicate the ways in which they frame the classroom. Particular noticing patterns point to particular frames. Furthermore, the authors add, a given teacher is capable of multiple frames, depending on the classroom’s context. Their theoretical ideas are elegantly demonstrated in a video-based study of a high school biology teacher in action.
Laboratory instruction came under the qualitative microscope this month in a report by Bretz, Towns, and co-workers. They studied how instructors of different laboratories prioritize cognitive (thinking), affective (feeling), and psychomotor (doing) learning goals. This work draws attention to a potentially concerning decline in affective learning goals as students move from general chemistry to organic chemistry. In other laboratory news, a simple apparatus for flash chromatography gives results comparable to traditional columns and “obviates the need for students to handle silica gel”, and instructors at South Dakota State University have reported on instructional design for a laboratory sequence aimed at producing student researchers.
The editor-in-chief of J. Chem. Educ. has written an editorial describing the costs of publishing, and rationalizing some recent price increases. It’s worth a look, particularly if you’re interested in the broader forces acting on academic journals these days. Also interesting are the editorials citations, which include familiar language from the journal’s past editors.
Other news: a really nice piece on learning progressions in Science; a perspective on the scale of acidity; development and evaluation of a chemoinformatics curriculum.
Demo This!: Trautz-Schorigin Reaction of Polyphenols in Green Tea
Periodically, I plan to cover a new demonstration from the recent chemical education literature in a feature I’m calling Demo This! Today’s featured demonstration comes from a recent J. Chem. Educ. article, which highlights the use of polyphenols in green tea for the luminescent Trautz-Schorigin reaction.
Background
Pyrogallol, or what we might call 1,2,3-trihydroxybenzene, undergoes an interesting set of transformations under oxidative conditions. In the presence of water, formaldehyde, base, and hydrogen peroxide, pyrogallol is oxidized and excited singlet oxygen is produced. Relaxation of singlet oxygen to its ground state produces red luminescence.
The Trautz-Schorigin Reaction: see if you can draw a mechanism for this beast!
A quick literature search has revealed that this reaction has been understudied (or at least underpublished) over the years. See if you can draw a mechanism accounting for all the products! All manner of oxygen-containing species may be present under these harsh conditions, including superoxide anion and hydroperoxide anion.
This reaction can be slowed or prevented by treatment with boric acid (forming cyclic borate esters, which are resistant to oxidation) or by treatment with ascorbic acid, which can reduce the 1,2-keto intermediate back to pyrogallol and (in a separate reaction) react with singlet oxygen. Considering these quenching reagents, this demonstration has all the trappings of a “green,” easy-to-prepare experiment.
Experiment
This demo can be carried out either with the parent pyrogallol or with polyphenols found in green tea. Either way, set up is straightforward, and the article claims that the entire kit and kaboodle takes less than one hour. Assuming that a tea bag holds about 2 grams of tea leaves, infusing for ~3 minutes in 200 mL of hot water is long enough to push a sufficient quantity of polyphenols into the water. Paraformaldehyde and sodium carbonate are then added to the hot tea with stirring, and the solution is allowed to cool to room temperature in a water bath. The pH of the solution is checked using pH paper or indicator before adding hydrogen peroxide (it should be ~11). 50 mL of the pH 11 solution are transferred to an empty beaker, and the lights are killed. Finally, 50 mL of dilute (3%) hydrogen peroxide are added. Luminescence should be instantaneous, and lasts for 5-10 seconds.
Ascorbic acid completely shuts down the reaction, while boric acid only slows it down. These quenching reagents should be added just before the lights are killed, right before the addition of hydrogen peroxide.
Source
Panzarasa, G.; Sparnassi, K. J. Chem. Educ. 2012, ASAP. doi: 10.1021/ed200810c
Chemical Education Roundup, 8-16-11
It’s been a while since I’ve done a roundup! The world of chemical education has been relatively quiet over the last month, although a few interesting things have happened (mostly in education-at-large). A while back, I blogged about Moskovitz and Kellogg’s intriguing idea of “double-blind science writing“—setting up laboratory experiments and reports so that neither students nor graders had an expectation of what their results should be. The aim of the exercise is to rip the bed of procedural and predictive comfort out from under students’ (and graders’) feet. Such a setup, argue the authors, forces students to use well-supported, rational arguments in lieu of the regurgitative, droning garbage that one usually sees in lab reports, and forces graders to evaluate students’ arguments as arguments—just as they would evaluate an academic paper.
On July 29, Science published a brief retort to the Moskovitz paper by Michael Goggin, a physics instructor who argues…
The first priority should be ensuring that the students get the correct result; their ability to articulate that result is secondary. (emphasis mine)
Goggin’s stated objection is that Moskovitz’s approach aims to teach writing more than science. However, in my opinion, a sufficiently open-minded scientist should take issue with Goggin’s assumption that the ideal lab experiment has “the correct result.” On the contrary, conservative experiments with spelled-out “correct results” lead students to believe that a career in science consists of proving what is already known. As any blue-blooded scientist knows, the opposite is true—most scientists spend their careers convincing others that their work is new! The work of undergraduates does not have to be new per se, but it should be new enough to them that constructing a convincing argument requires learning, not just regurgitation. Moskovitz’s approach to scientific writing is thus a step in the right direction. In a response to Goggin, Moskovitz and Kellogg offer this argument and others (among them: lectures give ample opportunity for students to find “correct answers”) in support of their ideas.
A little closer to home for me personally, Neil Selwyn has written an intriguing editorial in the British Journal of Educational Technology about the need for “pessimism” in the field. I put “pessimism” in quotes because what Selwyn argues for is less pessimism and more “healthy skepticism.” Selwyn states (truly) that there is an obsession among educational technologists with the use of technology as representing “progress” in education. Technology use seems to be associated with progress everywhere else in our lives—why should education be any different? Of course, in all aspects of human life, technology has its downsides. Selwyn argues (again, truthfully) that educators that use technology are often blind to the limitations, pitfalls, and “everything old is new again”-ness of what they do. How much in educational technology is actually new, he asks? Less than we think. ETs need a fresh challenge, a kick in the pants, a wake-up call that alerts us to the fact that what we’re doing may not be all it’s cracked up to be—which could be a good thing! Connections to past scholarship (and challenges to move beyond it) will only do good for the field of educational technology in the long run.
Other news and editorials: an interesting study of central nervous system drugs using calculated electrostatic potential energy surfaces, the harsh realities of narcissism and grade inflation, and a piece from the EIC of the Journal of Chemical Education on striking a balance with assessment. If you haven’t already, read about the epic standardized-test cheating scandal in Atlanta referenced in the last article.
