Development and Student Use of Web-Based Prelabs

Brian M. Tissue
Department of Chemistry
Virginia Polytechnic Institute and State University
Blacksburg, VA 24061-0212

This document is an annotated summary of a talk presented by Brian Tissue at the 54th Northwest Regional ACS Meeting, Portland, OR, June 20-23, 1999. It provides an update on the Web-based prelabs used in a senior-level Instrumental Analysis course. Annotations are in green.


This talk reports on four years of student use of Web-based prelabs in senior-level Instrumental Analysis. I developed and implemented the prelabs to replace time-inefficient prelab lectures and to encourage greater student independence. Students completed the on-line prelabs before the beginning of their lab period. The prelabs consisted of text and graphical tutorials, interactive instrument tours, and multiple-choice questions. Student and instructor perceptions indicate that the prelab assignments helped prepare students for their lab work.

The overall effectiveness of the prelabs depends on students taking primary responsibility for their preparation and outcomes in lab. Incorporating these prelabs into the course has made evident the need for a curriculum that prepares students for such independence. The on-line prelabs have also highlighted the challenge of teaching students to choose and use effectively an appropriate learning tool. A large variety of learning tools; lectures, textbook, lab work, multimedia, and library resources; can create a fragmented learning environment.

The last part of this presentation discusses some of the costs of using information technology (IT) in education, focusing on the decisions educators must make to provide an effective learning environment.



Instrumental Analysis

Costs of developing and using IT


Educational Uses of Computer and Network Technologies

One-way communication

Electronic communication is fast but not necessarily effective. E-mail messages take more time to compose than verbal announcements and I many users do not know how to use e-mail well. My second response to a question on an abstract topic is to come see me.

Two-way communication

The effectiveness of using these tools depends on the nature and size of a class.


Quality control can be lacking, which highlights the need for educators to help students develop critical analysis skills to be able to evaluate resources they find.

Computer-assisted or on-line tutorials, tracking, and testing

The rapid development of on-line courses raises the question of the purpose of a bachelor's degree. Is it a certification process or an experience?

Educational Technologies
magic lantern video cassette
movie projector videodisc
broadcast television desktop computer
slide projector DVD-ROM
overhead projector Internet

Various technologies have been touted as being able to revolutionize education. How many broadcast television shows would you consider educational experiences? I have seen the overhead projector (developed in bowling alleys years before they were common in classrooms) used brilliantly to enhance both learning and hypnotic trances. I do think that the Internet is different from many of the other technologies listed here, which are primarily presentation tools. The Internet provides a new communication tool and a huge "virtual library," although currently a library with little quality control and rudimentary search tools.

I agree with Laurillard that dialog between an expert and a novice learner are critical for effective learning. Technology might facilitate (or obscure) dialog, but it currently cannot replace it.

Reasons to Use Information Technology in Education

I think the first item on this list is probably the most compelling reason to use information technology in education. Graduates probably need computing skills more than any other technical skill - yes, even more than being able to record an NMR spectrum! Improved learning effectiveness is tough to measure but it can be done - requires looking at sub-groups in a class.

The last comment was made to me in jest about a course syllabus that hadn't changed in 30 years. A side benefit of widespread use of IT in education is that educators are taking a critical look at what we do to help students become independent learners. One, hopefully short-term, problem is fragmentation of the learning environment as more resources are added to a course or curriculum.

Interactive Programming Methods

Client-Side Methods

Server-Side Methods

Client-side methods are good for developing practice exercises or adding interactivity to individual web pages. Java can produce sophisticated presentations or simulations but requires some proficiency at programming. Server-side methods are needed to access a database or log student usage or answers. Commercial packages, such as Blackboard-CourseInfo or WebCT, are now developed sufficiently for the most common teaching tasks, i.e., delivering information, on-line testing, grade administration, and communication.

Senior-Level Instrumental Analysis Lab


The lab stresses hands-on experience with a wide variety of modern analytical methods (approx. 12 instruments) and tries to meet the needs of students who will go on to professional school or into the chemical industry as B.S. chemists. Higher-level skills are stressed in a capstone team project that replaces the final exam in the lecture part of the course. Most final projects have been a proposal to sample and characterize a Superfund site in eastern Virginia. The final grade was based typically on 50% lab (mostly notebook), 30% exams, and 20% final project.


Statistics Excel spreadsheet excercises
Spectroscopy atomic emission
atomic absorption
UV-vis absorption
Separations gas chromatography
size-exclusion chromatography
solid-phase extraction and HPLC
supercritical-fluid extraction
Electrochemistry fluoride-selective electrode
cyclic voltammetry
polarography (recently replaced with anodic stripping)

The first lab is a statistics lab to get everyone up to speed with Excel. The student groups then cycle through a set of three or four experiments in a four week sequence.


Prelab Example: Atomic Absorption Spectroscopy
(from the Winter 1999 CONFCHEM paper, opens in a new window).

The prelabs are mostly HTML with image maps and JavaScript in the instrument tours. The multiple-choice questions use a server-side PERL script to log student grades. Preparing the graphics was especially time-consuming and I was lucky to have NSF funding to hire student help.

Student Use and Perception

Student perception of the prelabs during 1997 and 1998. - The responses suggest that the prelab exercises helped the students to understand the underlying concepts and to prepare for the laboratory experiments.

Desire for more prelabs. - The students are neutral to having more prelabs to prepare for lab. They are positive about having computer-based material to help learn the lecture material. On the surface, this response would indicate that the students value the on-line material. Unfortunately, it also highlights that the students might not be recognizing that the prelabs cover the same material as in the course lectures.

Student-reported time-on-task to do the prelabs. - The difference between 1997 and 1998 highlights the change in grading. During 1997 full credit was given for the on-time prelabs regardless of the student's answer. Approximately half of the class clicked through the prelab questions too quickly to obtain any benefit. In response to student feedback, the script was changed to give full credit for correct answers, half credit for wrong answers, and zero credit for late prelabs. During 1998 the students took the prelabs more seriously and spent more time reading and answering the questions.

Comments on the survey forms indicate that students consider the instrument tours useful. In the current implementation of the tours, there is no logging of completion to know if everyone looks at them. The students are very positive about having the flexibility to do the prelabs at their convenience (often late at night).

Costs of Developing and Using IT

Monetary Costs

Installation and maintenance costs are sometimes hidden because faculty or students are doing these tasks.

Space Costs

Time Costs

Development tools are getting better, but standards and file formats are continually changing.

I present these costs because many of them are not obvious and can creep into an educators to-do list. However, they are changing the teaching and learning environment rather dramatically. As educators I think that we must teach students to use the modern tools of the profession. The question is how do we do so effectively and efficiently?


A short-term problem is fragmentation of the learning environment by adding more resources. A side benefit of introducing IT in a curriculum is that educators are taking a critical look at what we do to help students become independent learners.


Other Contributors



For more detailed presentations see:
    M. R. Anderson and B. M. Tissue, "Development and Student Use of Web-Based Prelabs in Analytical Chemistry Courses" Winter 1999 CONFCHEM: Teaching Spectroscopy, Dec. 1999;

B. M. Tissue, "The Web: A Revolutionary Resource or Just One More Addition to the Chemist's Crowded Toolbox?," Furman University National Symposium on New Information Technologies and Liberal Education, Greenville, SC, May 5-7, 2000.

  Copyright © 2000 by Brian M. Tissue, all rights reserved.

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