Projects by Department | Proposal Guidelines | LTLC Homepage

INCORPORATING COMPUTERS INTO FIRST YEAR CHEMISTRY LABORATORIES

Report

My project involved the evaluation of two data-gathering computer systems for eventual incorporartion into first year chemistry laboratories. The preparation of new experiments utilizing the selected equipment was a part of this work.

My technology project was rather different from any that I have undertaken in the past. It involved making a decision about which data acquisition system should be selected to implement the Chemistry Department's plan to incorporate computer technology into our two freshman chemistry courses, Chem 153a, Chemical Principles, and Chem 154b, Inorganic Reactions. Early on it became apparent to me that the constraints that would effect the decision were money (coming from our department's portion of the Sherman-Fairchild Foundation grant), accuracy of the data probes, range of applications, documentation, and ease of use by students.

Our proposal to the Sherman-Fairchild Foundation stated that we would purchase Vernier Software Serial Box Interfaces and Macintosh computers. During the eighteen months after we wrote the proposal two new systems came on the market, each of which has particular strengths and weaknesses. Because of circumstances within the Chemistry Department last summer and fall I was able to examine only two of these devices, but, in retrospect, tackling three would have been far too time consuming. Based on literature provided by the manufacturers I decided to work with the Vernier unit and one called LabWorks, which also uses Macs, produced by Jones and Bartlett Publishers.

First, let's look at the accuracy of the results available from the two systems. It turned out that there is essentially no difference using either the Vernier unit or LabWorks. Both measure voltages to ± 1 mv, temperature to ± 0.1 oC, and pH to ± 0.01 pH units. These are suitable for first year courses and for some applications in higher level courses.

When range of applications is considered the edge definitely goes to LabWorks. Jones and Bartlett has an excellent laboratory manual for first year courses with a wide selection of experiments that have carefully detailed instructions. A lab manual is also available for the Vernier equipment. It's directions are fine but it does not contain as many experiments as the J&B manual. However both look too much like cookbooks and so we will prepare our own lab handouts, as we have done in the past. The LabWorks hardware is far more impressive looking and in fact can do more things than the Vernier equipment.

The documentation on how to set up and use the equipment is an important aspect of all instrumentation. Both manuals leave something to be desired in terms of clarity, but after many hours with both systems the Vernier material began to make more sense, especially in terms of the next constraint.

Ease of use by the lab instructors as well as students is a most important consideration. I had some students do some work with the Vernier system making pH measurements as base was added to an acid (a pH titration). They seemed to have no problems with the software in terms of selecting input variables and setting up the computer to produce a useful plot. Unfortunately I did not have the LabWorks equipment available at that time for them to use. My own experience was that it was far trickier to set up the computer with LabWorks than with the Vernier unit. Adding to some of my difficulty with the LabWorks software were some keystrokes that were not intuitive, i.e., I had to use not so obvious steps to get to a certain point. With time and practice this certainly will not be a problem.

Finally, the bottom line, or cost, comes into play. The LabWorksII Basic System is priced at $783 while the LabWorks II Chem System, which includes 5 useful probes, comes in at $988. The Vernier Serial Box Interface costs $129. Probes, which are extra, range from $28 (temperature) to $129 (pH).

My conclusion should be clear from what I have said above. I have recommended that the Chemistry Department purchase the Vernier Serial Box Interface and appropriate probes. By purchasing used Macs and using the Vernier equipment our available funds can be stretched to enable us to set up eight systems in a first year laboratory. Soon after I came to this decision (in November) Vernier announced an improved version of their software package which will include full spreadsheet applications. It will be available in a few months.

I have not produced as many new experiments as I had hoped, but have made a start. A simple one, used with students in Chem 173a, Enhanced Chemical Principles, used a pressure sensor to verify the ideal gas law. They found this easy to do and obtained some excellent results. Students in Chem 174b, Enhanced Inorganic Reactions, will use computer systems in at least two labs. The first one studies intermolecular attractions by having students prepare time/temperature plots of various liquids as they evaporate from a temperature probe. A simple experiment, but it will make students think. A second experiment will have students study the relationship between concentration of crystal violet and the time elapsed during its reaction with sodium hydroxide. Here we will use our computer equipment connected to a colorimeter so that students can follow the change of light absorbance (which gives the concentration of the crystal violet) with time. In these experiments the "enhanced" students will serve as guinea pigs and from their observations I will revise the experiments for use by the entire class the following year.

My initial proposal from last spring contains other experiments that I will tackle as time permits. However I feel that a good start has been made and the biggest hurdle has been passed. I wish to thank the Technology Committee for your role in helping with this project.

Last updated on 1/26/99; 1:52:07 PM
Send questions about this page to: Herb Ellison
or contact Wheaton College.