Voltage Plotter Ill Vernier Software. 2920 S.W. 89th St.. Portland, OR 97225 Hardware Components
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Voltage Plotter I l l Voltage Input Unit pH Amplifer & pH Electrode High School, pH meter $154.95
Level and Subject: cost:
Summary Ratlngs:
Categoly Ease of Use: Subject Maner Content: Pedagogic Value: Student Reaction:
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Voltage Plotter III is a data gathering and displaying tool that may be used to measure directly electrical potential difference with respect to the computer's ground (voltage) a t a given instant or a t selected time intervals. Similarly, i t may be used to measure indirectly the pH of a solution. Each of the functions requires that peripheral devices be connected to the computer's game port. A voltage input unit with test clips-red for signal to be measured and black for ground-is used in direct voltage measurement. For measuring pH, a pH amplifier is plugged into the voltage input unit and a gel fdled pH electrode is connected to the amplifier. I f a measurement uf voltage ur pH i~ made, the reading may be displayed on the monitor in large digits Data arc gathcrcd at cstahhshed t m e inwrvsl.s and saved to a data dlsk to be m a ~ h e dat some later time, or they may be placed in a data table Gaph a s each successive measurement is made. The table and/or eraoh mav he minted. Numbers. exceut time. m e disolaved in thr& sren i & a n t ' d i ~ t sin the dataiable;. The length oitime during whit-h readings arcto be taken isdcterminrd by theuser and the numhrr of readings &red is limited by the computer's memory. If the user wants to save the collected data, this must be done before a new experiment is begun, otherwise the new data will be written over the previously collected data. Voltage Plotter I11 could be used by the teacher in demonstrations and by individual students or groups of students incollecting data in a laboratory setting. Owing to the fact that secondary school students are in a hurrv and not alwavs willine to read the documentation, this revlewer would recommend that the use of the software and peripheral devices be demonstrated and explained by the teacher prior tn its use. If Volmp Plotter 111 ir to be used to measure pll, it ir necessary that cahhratrm usmg two buffer sulutiuns ofknown pH be done befjre the electrode can be usrd. The clcetmde is tn bc rinsed in distilled water, and users must be aware of proper storage techniques far the electrode. The documentation of the software package is excellent. Included are sneeific instructions for the connection of each of the neriuheral dkviees to the wmuuter. I t also contains troubleshooting information. The hack of the disk includes files that may be used by people who wish to mdify the program Thrsc filcs are dererihed in the printed doeumcntation. Each main menu and
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submenu option is explained clearly, a s is the interfacing with a printer. The program performed exactly as indicated in the d m mentation. The sophistication of the graph option allows the user to choose from automatic or manual scaling, and to elect to connect the points on the plot or to use a least squares regression line. Additionallv. . v, ". a statistical function will urovide the user with s h e~. mtercept, and a carrelatam cwlficwnt of the regression h e . Any numhrr of these options may be selected and used simultaneously from a n on-off menu. The user may move from one function to another with ease hy pressing the escape key. Collected data may be saved on a formatted ProDOS disk. Since PraDOS limits the size of the volume directory to 51 files, lt may he necessary to use ~uhdirrctories.Data may beswred in a file type that will transfer to Appleworks; how. rvcr, this file type cannot be loaded back into Volmge I'lotter Ill. The program allows the user to set alarms that can be used to monitor the process from which data is being collected. This feature permits the experimenter to carry out other tasks while the experiment is in progress. Further, the voltage input unit contains special circuits that prevent damage to the computer if the input voltage is above the specified upper limit of 3.4 Y This is especially important when students are using the equipment. Voltage Platter I11 may be extended to include peripheral devices that can be calibrated and used to measure indirectly other quantities. The documentation includes the suggestions t h a t strain gauges be used to measure force, and that a thermocouple or tcmpcrnture probe be used tn measure temperature Circuit diagrams are rneluded for each of these as well as for modfyng the vultage input unit tu allow the readmu of buth higher and lower voltages. Students who have used Voltage Plotter III found it easy to use and were pleased that data readings were made automatically rather than their having to mark time and read. They certainly expressed an appreciation far the use of technology in research. The fact that data files could be transferred to a n Appleworks s~readsheetallowed them to ahserve the effect of several trials on the results of a n experiment. The calibration for the use of the pH probe provided the students with a n important learning experience. In summary, this rcvicwcr found the largcdigit display ofvoltah- Plvttcr 111 to be a lueful tool to make r e a d m ~ vtaken during demonstrations visible to the students. Also. the devices in the kit could he used to monitor changes i n potential difference that occur over long periods of time, and to monitor indirectly the pH of a reaction svstem. Valtaw Plotter 111 is easv and safe to use and provides s t u d e n ~ swnh a n understanding of and an appreclatmn for the apphcation of technolugy lo the c u l l e a m and analysrs uf dam. Owlng w the vrraatilit). of the sonware and voltage input unit, this reviewer would recommend it a s a valuable addition to any high school science laboratory. ~
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G o r d o n K. Horgen Winner Hiah School P.O. Box 231 Winner, SD 57580-0231
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Reviewed in This Issue
Reviewer Computer Learning P a c k a g e s and Fhm VernierSoflware, Voltage Plotter I l l Dmitr~Mendeleyev: Father of t h e Periodic Table Books
Gordon K. Horgen George B.Kauffman
A1 3 9 A1 40
S~dneyHarris, C a n ? You Guys Read? Cartoons on Academia
Geroge B.
Kauffman
A1 40
Volume 69
Number 4
April 1992
A139
