from Inquiry, Volume 3, Number 1, Fall 1998, 6-8
© Copyright 1998 Virginia Community College System
Abstract
The CBL unit is versatile, portable, and reasonably priced. Use of the CBL will provide opportunities for real-life applications of math functions, quick and accurate scientific data collection and analysis, and easy transfer of data to computers.
How do you show the connection between lecture and the real world? One answer useful in math, chemistry and biology is the use of a calculator based laboratory (CBL) system. The CBL system consists of a relatively small hand-held unit to which different probes may be attached that will measure temperature, acidity, motion, or force. The unit is also connected via cable to a hand-held Texas Instruments graphing calculator of the type that is used in mathematics courses. Additionally, the unit comes with a small, waterproof carrying case that contributes to its portability. The entire system runs on batteries.
There are several features about this equipment that make it appealing for use at a community college. Because the system is lightweight and portable, it is easily transported outside the classroom and into the field for data collection and analysis at places like our local nature park. This park, which is close to our campus, has two lakes, one which is teaming with life and the other which is relatively lifeless. The students’ preliminary studies of these two diverse ecosystems have generated interesting findings about the effects of differences in acidity and temperature. In addition, the students feel as though they are doing "real science." By taking water samples at different sites and at various depths throughout the lakes, they have developed profiles of the lakes for use by the park management
In the math class, this equipment can be used to give a real-world flavor to the lecture. Often, we discuss sine waves, power functions, and linear equations. With the CBL equipment, these topics can be quickly demonstrated, adding another dimension as the students get a better feel for the origins and the use of the principles they are learning. As an example, the motion of a weight attached to a spring can be described by a sine function. Weights and springs can be brought into the math class, their motion can be analyzed, and the students can see the "real life" application of the math functions that they are studying. The entire demonstration takes only five minutes and has such an effect on the students that it is considered to be a good use of the class time.
In addition to analyzing data using the calculator, we are also downloading data to a computer in the laboratory. A special cable allows the calculator to be connected to the computer, and a program allows the two machines to transfer data to each other. Using a computer allows a clearer display of the data and ease of analysis and manipulation. Educators believe that the more we expose students to computers, the better prepared they will be in the future. We have already given the students some data analysis exercises to enhance not only mastery of the subject matter but also experience with the technology.
There is no doubt that time is a scarce resource in the classroom. A nice feature of this equipment is that data collection occurs quickly. Students spend much less time gathering data and much more time analyzing it. Indeed, one author reflects on a general physics lab done as an undergraduate. The experiment involved the motion of a falling object. A ball was dropped and photographed using a strobe light. Coordination and setup took an hour. The picture showed the position of the ball at several points in time. This data was painstakingly converted by hand to a graph and analyzed. Using this technique, the experiment lasted two hours and contained a great deal of error. Using the CBL, the same experiment could be run in less than five minutes with much greater accuracy: simply align the motion sensor, drop the ball, download the data to a computer, and produce a graph. Using the CBL will allow the students to perform more experiments with more variables, thus obtaining a fuller understanding of the phenomenon being studied.
Another great feature of this system is the versatility. With one device and a few probes, a student can make several types of measurements. It must be pointed out that this device can be used to take the place of several other devices that were dedicated to only one type of measurement. By investing in the CBL and probes, a school would not need to purchase a pH meter, a spectrophotometer, a Geiger counter, an oxygen meter, a carbon dioxide meter, or a manometer. The CBL and probes take the place of these expensive machines. Schools that are considering upgrading equipment would be well advised to consider CBL for economic reasons alone. Basic CBL packages start at $300, and complete packages, with all the probes needed for experiments in a discipline, cost about $600.
Using the CBL unit also has given us an excellent opportunity to interact with local high school teachers. We have made several presentations in which we demonstrated the application of this technology in an integrated format for use in the high school curricula. Many secondary school budgets cannot accommodate computers in every classroom, and the CBL offers them an affordable alternative for that technology. Further, school systems are receiving this equipment and implementing it as a means of fulfilling the Virginia Standards of Learning.
Through our presentations, we have been asked to provide a for-credit special topics course for a local high school as part of their "in-service" program. Although the intent of this project was to improve teaching and learning at TNCC, we are pleased to see that it will also allow more interface with the community, as well as generating additional FTEs.
Most importantly, this project was well received by the students. One author directed a lab experiment, a titration, in which students used the older methods and graphed by hand. When the same group of students repeated the experiment using the CBL and the computers in lab, the time spent on gathering and analyzing data was cut in half. Moreover, the students unanimously preferred the CBL. Some students’ comments were: "The CBL was more accurate. The CBL was quicker. The graphs look better. We enjoyed using state of the art equipment. CBL was more efficient."
In closing, the CBL equipment has provided many benefits to teaching and learning. It provided opportunities to interact with the high school teachers in our service area. Math and science teachers would be well advised to consider using this equipment.
Acknowledgements
The authors graciously acknowledge the assistance of several individuals in the completion of this project. Our appreciation goes to Barbara Mowery, Susan Fortunato, Robert Auerbach, Duane Stephens, and Eryn Welch.
This project was funded by a VCCS professional development research grant.
Steve Arnold is an instructor of chemistry at Thomas Nelson Community College. His current interests are the use of technology in the laboratory and laboratory simulations.
Jacqueline Spencer is an instructor of biology at Thomas Nelson Community College. She involves her students in science activities in the community. Her focus is incorporating the World Wide Web as a resource for biology education.
Pat Taylor is an assistant professor of mathematics at Thomas Nelson Community College. Her interests include bringing science into the mathematics classroom and utilizing technology in learning math concepts.