The Department of Chemistry at Oregon State University has been offering an online general chemistry sequence since 2003. We have struggled to identify a method of facilitating an appropriate distance laboratory program. We have investigated a "kitchen" chemistry kit and various online virtual toolboxes. We are currently using a virtual laboratory package (www.onlinechemlabs.com) which presents the user with a split screen: one side contains chemistry laboratory tools and the other is text. The tools include standard experimental equipment such as an analytical balance, flasks, pipettes, and reagents, as well as more complex analytical instruments or reaction equipment such as an absorbance spectrophotometer, calorimeter, NMR, and a combustion chamber. The logical progress (or flow) of these tools in experiments is analogous to that in classroom labs. The tools incorporate both random and systematic error, providing data simulations where detailed error analyses can be performed that are analogous to that in classroom laboratory experiments. Each of these features allows for a significant enhancement in instructional capabilities, and could integrate very well with the instructional modalities of models and argumentation that have been recently developed and outlined in more detail below.
An analytical balance functions similarly to a real-world balance. The balance has a weighing dish and is tared, the tare works exactly as in a real-world setting. The mass display updates once per second, and fluctuates with an assignable random error (typically +- 0.002 g). Solid reagents are massed by placing reagent bottles on the stand is clicking a dispense button (1, 0.1, or 0.01g), the powder dispensed into the weighing dish amount is only within 10% of the nominal value. Other tools for to be weighed (such as P2O5 and NaOH traps for the combustion tool, or electrodes for an electroplating tool) are placed directly on the balance. The overall simulation is quite remarkable; after the first use both new students and experienced chemists have the uncanny sense that this balance is displaying real data.
The framework for the curriculum development proposed in this virtual laboratory is based on authentic science inquiry that highlights model-based reasoning and argumentation process in knowledge building. We examine and elaborate the nature of scientific inquiry in those two critical aspects and then discuss the utility of engaging students in these processes in the curriculum to be developed in this project.
New online lab tools from are excellent matches for several modes of learning. In our current real-world laboratories, students work with physical models of molecular structures to explore features such as bond angles and equivalent ligands. Experimentalists do not really learn about structures in this manner. Direct access to an NMR spectrometer is clearly not a possibility, nor would this be a suitable experiment for general chemistry students. However, given a number of proposed molecular structures, students can predict the ligand equivalencies and, with a brief explanation as to how NMR can differentiate distinguishable ligands, students can predict the main features of the NMR spectra for different structures. Using simulated 19F NMR, SF5CH3, which shows a two peaks in a 4:1 intensity ratio, is therefore seen as consistent with the octahedral coordination about S, but not with other geometries. Subsequently, students can be given the SF4(CH3)2 sample and be asked to establish a method to determine which structural isomer is present. The students can test their model of molecules of this type by predicting and then observing NMR spectra of SFx(CH3)y examples.
As another example, the virtual laboratory has developed a synthesis tool, where students control the combination ratio of reagents that will combine to form a single product. A thin layer chromatography (TLC) simulation is provided to test each product batch to determine whether a correct stoichiometric ratio was employed. If so, the chromatograph shows only a single spot (with Rf appropriate and matched to a product standard), otherwise one or more reagent spots are observed and can be similarly identified. This type of experiment would be difficult to perform in real world general chemistry laboratory, but the simulation permits students to observe the outcome quickly if the measured amounts were correctly determined. Or, when the student mixes reactants in the correct ratio but observes that both product and all reactants are present by TLC analysis, a guided realization comes that insufficient time was allowed for the reaction to run to completion. This hypothesis can then be tested, with the result that the student feels comfortable that a full understanding has been reached.
