Tasker GROUP
Visualizing Chemistry
An essential goal of all our research is to improve student learning outcomes through refining evidence-informed teaching practice.
View Our ResearchView Our practice
The core group presently involves three graduate students, with a postdoc researcher and an animator to join us soon. We also have graduate students in Gabriella Weaver's group working with us, and undergraduate students helping out.
View their profiles
On 5 February 2016 Roy presented a keynote and follow-up workshop at the Chicago Symposium Series ...
We celebrated our first Christmas holiday together as a group. Before we ...
Elijah's teaching performance as a TA was rated as “Exceptional” in Fall semester 2016 ....
A central focus of organic chemistry is the conversion of carbon-based molecules into other molecules. Functional groups in these molecules can be classified into Levels 1, 2, 3 or 4 based on whether there are 1, 2, 3 or 4 bonds between a particular carbon atom and more electronegative atoms (O, N, P, S, or a halogen, X). This scheme was developed by James Keeler and Peter Wothers at Cambridge University.
Converting molecules in one level to a higher level involves OXIDATION (decreasing the electron density on a C atom), and to a lower one involves REDUCTION (increasing the electron density on a C atom). Conversions within a level simply involves swapping one electronegative atom with another. In this way you can see whether you need an oxidizing agent, reducing agent, or a non-redox reagent for a specific conversion.
Visualizations like this can organize lots of ideas into meaningful 'chunks'.
The long-chain molecules in nylon act like sticky cooked spaghetti, lying on top of one another. The dotted lines are weak bonds (hydrogen bonds) between the molecules. So it's a bit like a zipper, where even though all these bonds are weak, there are so many of them, the molecules can't slide over each other. So nylon does not stretch, but it is flexible.
Here we can see the rubber sole getting compressed, with its long-chain molecules squashed closer together. They can’t slide over one another because of the strong bonds (covalent bonds between sulfur atoms shown in yellow) between the molecules. As the molecules are squeezed together the big bulky groups (hexagonal phenyl groups) hanging off the chains repel one another. This is why rubber is compressible and returns to its original shape.
The chemistry education research literature demonstrates that many student misconceptions are due to an inability to visualize substances and reactions at the molecular level, due mostly to misinterpretations of the meaning of chemical formulas and equations.
We need to help students to develop useful mental models of the molecular world to make sense of chemical concepts like equilibrium, entropy, chemical speciation, and hydrophobicity, and to make conventional symbolism meaningful.
However, we know that we cannot do this by simply showing students complex visualizations, that portray our expert mental models of this world, and then just expect novices to adopt them for understanding chemistry concepts. We use a cognitive learning model to inform how we use visualizations.
