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Virtual chemistry labs allow first-year students to learn basics online
BY ANDREW VOWLES
Chemistry class wouldn't be chemistry class without hands-on lab experiments. Just ask the thousands of students who visit the science complex teaching labs every week, including more than 1,500 students in first-year general chemistry. But for the past four years, students taking that introductory course — known by its undergraduate calendar appellation of CHEM1040 — have completed two of those requisite lab modules without setting foot in the science complex or the former Chemistry and Microbiology Building.
Now, based on the success of its “virtual chemistry” computer labs, the Department of Chemistry plans to introduce a third electronic lab module next fall, says Prof. Bob Balahura, department chair and co-ordinator of the introductory chemistry courses.
Although students still conduct hands-on lab work for most of their first-year material, they must log into the course website to conduct two groups of experiments — volumetric analysis and atomic spectroscopy — directly on the computer screen. Next fall will see a nuclear medicine unit added to the course roster of virtual labs.
Balahura says introducing computer labs for certain experiments helps course instructors handle large numbers of students more easily. The particular modules allow students to learn and reinforce core analytical principles on their own time rather than in scheduled teaching labs, he adds.
The online experiments — designed by Balahura and Uwe Oehler, the department's software specialist — lead users through demonstrations on the computer screen with both printed text and an instructor's voiceover. Using click-and-point, students manipulate virtual lab tools and materials to perform the experiment, including everything from choosing appropriate equipment to transferring liquids between containers.
In volumetric analysis, for instance, one experiment requires students to dispense precise amounts of liquid from a burette to cause another liquid in a beaker to change colour. Clicking on the computer mouse allows a user to vary the flow from a thin stream to a single drop. Just as in the teaching lab, they need to vary the experiment depending on concentrations of liquids and must perform calculations to yield a correct answer for the exercise.
In an atomic spectroscopy experiment, manipulating the mouse enables users to “dip” a platinum wire into various salt solutions and heat the samples over a virtual Bunsen burner flame. Coloured bands on a scale mimic the characteristic light wavelength patterns generated by emission spectroscopy equipment that indicate the presence of particular elements in the sample. (Balahura notes that the same principle lies behind colourful fireworks spectacles.)
Far from foolproof modules, the experiments were designed to enable students to make mistakes and have to repeat their work. Over-titrating, or adding too much liquid from a burette, may ruin a volumetric experiment, for example. Glancing at the computer monitor in his science complex office, he says: “This is real life. You may need to do it several times.”
Balahura says the virtual labs are intended to underline the importance of following prescribed lab procedures and analysis — in effect, using computer technology to teach not just course content but also how science works.
“They have a couple of weeks to do it,” he says. “They can be as careful as they want.”
He adds that students are marked solely on numerical answers submitted electronically at the end of the experiment.
Although he and his co-instructors have yet to analyze how computer labs affect students' learning, they have found that virtual and real labs complement each other. Prof. Lori Jones has seen benefits flowing both ways for students learning titration, or dispensing fluids to cause a reaction.
“Allowing students to complete the online lab prior to going into the wet labs gives them the opportunity to practise the conceptual aspects of the exercise in advance,” says Jones. “When they then actually carry out the wet lab, they can focus on the hands-on aspects.”
She notes that students were overwhelmingly positive in a survey about the online experiment.
Referring to hands-on labs in atomic spectroscopy, Jones says rotating students through the stations often became cumbersome. In addition, some students found scattered light from nearby setups interfered with their observations.
“With the online labs, everyone sees the same data, which makes identifying the unknown samples much easier.”
Balahura plans to introduce a third computer module on nuclear medicine in which students will manipulate kinds of radioactive isotopes used in medical imaging diagnostics. He's also considering another online experiment that would mimic an aspect of auto emissions testing.
His department has experimented in the past two decades with a variety of e-learning technologies to maintain quality instruction for students in large introductory courses. Since online quizzes were introduced in 2000, for example, failure rates in those courses have dropped from more than 20 per cent to 10 to 15 per cent.
