The students were instructed to read their experimental procedure and to do the relevant laboratory preparation exercise. The individual tutorial documents were primarily text that provided basic theoretical and experimental descriptions of analytical and instrumental methods. The documents included hyperlinks to basic concepts, simple schematics, and color graphics of experimental set-ups or instrumentation. We chose the World-Wide Web (WWW) as the delivery platform for this project because of the ease of developing, distributing, and modifying hypermedia material in a client-server system. The disadvantage of the WWW is that network bandwidth limits the size and sophistication of the hypermedia material. To minimize internet transfer time, the individual documents were kept short and usually contained no more than 3 or 4 inline images. After reading the tutorial the students answered several multiple-choice questions. The figure shows one example of a multiple-choice question and the response page. Clicking on the "Submit answer" button calls a *.cgi file, which contains instructions in the PERL interpretive language, that generates the response page and saves the date, time, and student's answer to a file on the server.

Usage and student perception of the on-line material was evaluated from server logs and student surveys. On-time completion of the assignments was 75%, but use of other on-line resources such as a question-and-answer page was minimal. Responses from student surveys indicated that the students had sufficient access to the internet. Approximately half of the students completed the prelaboratory exercises from one of several computers in the laboratory, and half worked from a workplace, university library, or home. Greater than 85% of all student usage from the laboratory computers occurred between 11 am and 4 pm. A mid-semester student survey indicated that the spectroscopy prelabs with three multiple-choice questions were better for increasing conceptual understanding rather than preparing the students for the actual lab work. An end-of-the-semester survey based on the electrochemistry assignments, which consisted of two multiple-choice questions and one clickable-map graphical exercise, produced a slightly higher rating for preparing students for the laboratory work. The differences between the spectroscopy and electrochemistry exercises prevent drawing any real conclusions from these two surveys, however, they do help guide the preparation of the content of future exercises. Next year's materials will contain three multiple-choice questions and one graphics-based exercise. The clickable-map graphics and at least one of the multiple-choice questions will be designed to test an understanding of the experimental procedure and instrument use to better prepare students for the actual laboratory work.

Acknowledgment

Literature Cited

1. Laurillard, D. Rethinking Teaching, a Framework for the Effective Use of Educational Technology; Routledge: London, 1993.
2. Tissue, B. M.; Earp, R. L.; Yip, C.-W. Chem. Educator 1996, 1(1), S1430-4171(96)01010-2. Only available at http://journals.springer-ny.com/chedr.