New Chemistry Tools for LON-CAPA

Matching Problems in LON-CAPA

LON-CAPA offers a variety of ways to present matching problems. The simplest involves the common "multiple choice" problem (called "Radio Response" in LON-CAPA) where a series of items or statements is listed with check boxes by each, and only one item is "correct". The statements can be selected randomly from a larger list of correct and incorrect statements, with the computer choosing only one of the correct statements to present in the list. In a true-false question, for example, only one of the statements would be true.

The more versatile "Option Response" problem matches items in one list (called the "foil") to items in another list (called the "value"). Each foil can have only one value, but the same value might apply to more than one foil. Using "true" and "false" as values, for example, allows one to ask a series of true-false questions. The foils can be randomly selected from a large list, or some variable in a foil or a value can be generated algorithmically with a Perl Script. The values can appear in a drop-down box next to the foil, or they can be given separately in a lettered list with the letters appearing in the drop down box. The latter method is required when the values are complex items such as images, chemical formulas, or items with some types of HTML formatting that cannot be displayed in a drop down list. Images can be used in either foils or values or both.

Foils can be arranged in "Concept Groups" with one foil randomly chosen from each concept group to insure that the question covers the scope of concepts intended.

Slight variations on matching can include comparing two or more items in a foil (which of three structures is not an isomer, are two structures the same or different, which temperature is greater, etc), or rank ordering values of items in a foil (order atoms by size, order elements by atomic number, order units by size, etc).

The common feature in these problems is that the student "selects" an answer from a predetermined set, rather than "producing" an answer in the form of a string, a numerical value, or a structure. Features of the matching problems can be combined with other problem response types, though.