Evidence Based Design: The Open Learning Initiative

ON THIS PAGE:

• Scenario-based Learning
• Virtual Lab
• The solution of the Bangladeshi chemist. (Try it in the OLI Chemistry course!)

Prior to beginning work on the OLI chemistry course, the chemistry group conducted an analysis of chemistry as practiced versus chemistry as taught. For evidence of the domain of chemistry as practiced, they chose for the Nobel prizes awarded for past fifty years along with all chemistry related articles for one year of the New York Times Science Times and Scientific American News Bites. This led to a conceptual map of the domain based on three main activities: explaining phenomena, analyzing matter, and synthesizing new substances. These activities are supported by a toolbox of basic notational and quantitative schemes. A similar analysis of chemistry as taught, based on the California state content standards and two best selling textbooks, showed significant misalignment, with traditional introductory courses focussing almost exclusively on the toolbox and the explain activity. (Evans, Karabinos, Leinhardt, Yaron; 2006) This misalignment is evidence that traditional courses do not meet one of the basic goals of scientific literacy, that of showing what chemists do. This misalignment also hides from students the very things that are most interesting about the field.

Much of college level chemistry is often taught out of context as a set of abstract mathematical skills. Students employ learning strategies to solve typical text book problems and perform well on traditional chemistry exams but often fail to see either the relationship between the mathematical procedures and the chemical phenomena those procedures represent or the relationship between the chemical phenomena and the real world. The OLI chemistry course is designed to address both of these educational challenges.

We address the challenge of connecting the mathematical procedure to use in chemistry by replacing traditional textbook problems with problems to be constructed and solved in the virtual chemistry lab. We use the virtual chemistry lab to create learning environments with ill-structured, ambiguous problems that require flexible application of procedural knowledge.

We address the second challenge of connecting the procedures of chemistry to the real world by employing scenario based learning. The OLI introductory Chemistry course situates the learning of chemistry in an authentic investigation that addresses questions that are significant to the domain of chemistry and to real world problems.

For example, The OLI Chemistry course unit on stoichiometry is situated in a real world problem of arsenic contamination of the water supply in Bangladesh.

The video above appears early in the course and introduces the student to the problem they will use the tools of chemistry to solve.

The video gives the student an overview of the real world problem, the distribution of arsenic in Bangladesh, the health effects of arsenic poisoning, the difficulty in discouraging people from drinking the contaminated well water because the well water is clear, and the arsenic is an odorless, colorless, and tasteless poison, the need for an inexpensive and easy way to test the level of contamination in each well and the need for an inexpensive and easy way to remove a sufficient amount of arsenic from the water to make it safe to drink.

Following the video, the student engages in a process to solve the problem as a chemist would. At each step of exploring a solution to the arsenic contamination problem, the student is introduced to and practices one of the target stoichiometric concepts or skills. In the very first step, determining the level of arsenic contamination in a sample of well water, the student uses the Chemistry Virtual Lab to analyze a well water sample and compare the level of arsenic found in the sample to the acceptable levels set by the World Health Organization. The challenge the student confronts is that virtual lab experiment gives them the concentration of AsO2 in units of moles/liter. The WHO gives its safety standard as 10 micrograms as As per liter. The student must be able to convert the results from the lab to evaluate the concentration of elemental arsenic in units of micrograms per liter. In order to evaluate the safety of the water, the student must either understand the concept of the “moleâ€? and apply dimensional analysis, composition stoichiometry and solution stoichiometry.

At one point in the course, the student explores a potential solution to the arsenic contamination problem developed by a Bangladeshi chemist who uses powders made from local bricks to make filters that remove arsenic form the water. In the course, the student uses the virtual lab to reenact the work of the Bangladeshi chemist.

In the video below you see a screen capture of a student working through the virtual lab problem as the student reenacts the work of the Bangladeshi chemist. We give the student samples of various powders in the virtual lab and ask students to characterize the powders' ability to absorb arsenic. Students must determine the amount of arsenic that can be absorbed by 100g of absorbent, to an accuracy of 3 significant figures.

As you view the video of the student working through the problem, notice that students may ask for hints as they design the experiment and get immediate feedback on the results. If a student enters the incorrect answer 3 times, the lab gives the correct answer and prompts the student to try again. The software then generates a new problem with different values.

The virtual lab in the course provides opportunities for students to interact with the environment by exploring and manipulating objects, wrestling with questions and designing experiments. Students find such experimental design problems considerably more challenging than text book problems but struggling with these types of problems supports better learning outcomes.

Click here to enter the OLI Chemistry course at the beginning of the 3 page that covers the solution of the Bangladeshi chemist. You can try the tutors and the virtual lab activities. The last page of the sequence has the virutal lab activity that you just viewed above.

An analysis of the data logs of student use from a study conducted on the OLI stoichiometry course revealed that the number of engaged actions with the virtual lab not only matters, it matters a lot explaining about 48% of the variation observed in the post test scores for students taking OLI. The number of interactions with the virtual lab outweighed all other factors including gender and SAT score as the predictor of positive learning outcome. (Evans, Yaron, Leinhardt; 2007).