students' answers with the correct answers, and then prints the tables of results. The printing and grading programs were written in COBOL. MDHS provides a convenient and reliable method for giving individualized homework assignments to large classes. It has been used successfully in classes of over one hundred students. It was desiened to work on the eauioment which was currentlv available, but it could be modif;eedadvantageously to run on other equipment. Listings of the homework-printing program, the homework-grading program, and documentation will he sent upon request Figure 4. Student answer card for computer-managed homework system.
Applications of Alphanumeric Calculators David Holdsworth
University of Papua New Guinea Papua, New Guinea FOLLOY I R S I R U C T I O W I C l l C T L I Y H C N * I R K I N G A W Y I I I 01111s. MOT 8s C I W N 1011 IIIPIIOPEIIIY M A R X E D I N S H E R C A R O I . C I Y E YOUR A W I Y C R I I N S I C H I P I C A N T IICUtTI. ONE "WD YE*.
LW011 MILL
SCIENTIFIC HOTITION ROUUDED 10 I H R C C THE MINTl5ll W I T BE I UU*8FR B l r W f l *
Innovations in designs and features of pocket programmable calculators continue. Storage capacity and the ability to nrocess data increases. A new generation of instruments. such as the Hewlett-Packard ~ k - 4 1 have ~ , the we~comd feature of disolav . .or .orintout of letters and svmhols as well as numhers. Words and numhers can he combined for storage, recall. and disolav. ~ h use k of prompt statements and conditional operations enables interactive student-calculator programs to he written, increasing their versatility and acceptability in class use. Previouslv, the student was expected to enter a series of numhers in a particular order and interpret the results of the operations by assigning functions, units, or formulae to a series of displayed numhers. Alphanumeric calculators enable questions to he displayed. The student answers the questions Table 2. Weak AcidlBase pH Calculations ( 6 ) on a Numerlc Calculator (HP-29C) Disolav
Enter 1.8 5
1.80
EEX CHS ST0 1
-05 .8
GSB 1
2.42 Figwe 3. Typical assignment sheet far computer-managed homework system.
5.25 EEX 4 CHS ST0 2 5.25
-04 ,273 GSB 2
After the student answer cards have been collected thev are read and punched on an IBM 519 document reproducer.-The nunched cards are then eraded hv MDHS. The svstem compares the student's answer withthe correct answer. If the student's answer is within 3.5% of the correct answer, the student earns the numher of points that that particular problem is worth. Tables are printed and posted giving each student's results for each assignment and the total numher of points earned to date. A summary of the results of each assignment and an error listing are also posted. The system was designed to run on an Itel As5-3, which is the equivalent of an IBM 3701158. I t consists of three programs: a prohlem-generating program, a homework-assignment-printing program, and a homework-grading program. The prohlem-generating program produces many variations of any selected problem and assigns point values for problems. The program used is the GENIE program developed by Paschke and Bentsen ( 5 ) ;however, other similar programs could he used instead. The output of the GENIE program is read by the homework-printing program which prints the individualized homework assignments and assembles a table of correct answers. The homework-grading program reads the student answer cards, makes validity checks, compares the
604
Journal o f Chemical Education
12.08 3.58 GSB 3 2.63
-04
SRO
-11
RIS
Student lnter~retation
Dissociation constant of weak acid = 1 8 X Molar canwnhation of weak acid = 0.80 pH of weak acid solution = 2.42
Dissociation constant of weak base = 5.25 X lo-' molar concentration of weak base = 0.273 pH of weak base solution = 12.08 pH of solution = 3.58 molar concentration H+ ions = 2.63 X lo-" molar concentration OH- ions = 3.8 X lo-''
Table 3. Weak AcidlBase pH Calculations on a Alphanumeric CalCulatM IHP-41C) Oisplay/FTint
Ka WlAClD = ? (W/ACID) = ? PH = 2.42 Kb WIBASE = ? (WIBASE) = ? PH = 12.08 pH
=7
(HA) = 2.63 E-4 (OH-) = 3.80 E-11
Enter 1.8 .8
A EEX 5 CHS RIS RIS
B 5.25 EEX 4 CHS RIS 2 7 3 R/S C 3.58 RIS RIS
Table 4. Analysis of a Mass Spectrum (7) on Numeric Calculator (HP-67) 0is~Ia~
Enter
Student interoretatian
45 A RIS R/S R/S R/S
maximum nitrogen atoms in molecule is 1 approximate m / e of each m / e peak = 45 C2 H7 N . . . C2H7N
RIS
l i r ~t peak mass = 45.0579
m
RIS
no double bonds or rings in molecule
RIS
-M+1-2.7%
RIS
M+ 2 -0.03%
R/S R/S R/S RIS RIS
M ratio M C2 H5
+ 1/M + 2 = 101
...
0
C2Hs0 m peak mass = 45.0341
-e
Second
RlS R/S R/S R/S
CI or 1 double band 8 ring in molecule CI H 3 N1 01 CHaNO m third -peak mass = 45.0215 e CI or 1 double bond 8 rino in molecule
R/S R/S R/S R/S RIS RIS RIS R/S
error
Enter
Oisalau/Print M/E ANALYSIS MAXN=? APPROX M/E = ? C2 H7 N 1 M/E = 45.0579 D.B. R. = 0 M 1 = 2.7% M 2 = 0.03%
+ +
+
M
R/S
R/S
Table 5. Analysls of a Mass Spectrum (7) on an Alphanumerlc Calculator (HP-41C)
... ratio M+l/M+2 CI HI
=7
...
R/S
02 C H 0 2 m fourth - peak mars = 44.9977
RIS
no more peaks possible
by entering numbers or words which are stored and processed, enabling further questions to he asked until all data relevant to the problem has been entered. he-calculator can display each numerical result in a statement, avoiding misunderstandings in data interpretation. User functions enable direct access t o a particula;sub-program and allow functions to be assigned to certain keys. Some examples are chosen in which student originally written for a numeric instrument can be made more useful and meaningful with an alphanumeric calculator (see Tables 2-5). I t can be appreciated that the student can often
+
M 2 = 0.21% M+I/M+2=7 CH02 4 MIE = 44.9977 M/E PEAKS = 4 MOL. IONS = 4 M/E ANALYSIS
R/S elc.
be in doubt in interpreting data continuously being displayed on a numeric calculator. Should he lose the sequence of the displays, his interpretations become meaningless. An alphanumeric calculator with a printer can not only print results with statements that a nonscientist can follow but also can automatically print graphs of results, in which the X and Y coordinates as well as the location of the X axis may be controlled. Graphic symbols can be designed on a 7 X 7 matrix and used in a graph or statement. A suitable program for an automatic graph printout would be counter-current distribution of a solute in different solvent systems, using a variety of solvent transfers (8). The pocket calculator now has features previously found in computers and desk-top calculators, yet retains its advantages in ease of programming and debugging, low costs, and portability from classroom, laboratory, and office. Literature Cited (1) "BuyingSolsr,"F. E. A./C-7611SI.FederalEnergy Administration. Printing Office, Pueblo, CO. (2) Beckman.
US. Government
W.A , Klein. S. A,, and Duflic, J. A,. "Solar Hearina h i m , " Wilev-Inter-
.-, ..... (61 Holdsworth. D. K.. School Science Reuinli, 58.88 (1976) (7) Holdsworth. D.K.. J. CHEM EOUC.. 57.99 (1980). (8) Holdsworth.D. K.. J. CHEW. E ~ ~ c . , 5 7 . 6 2(1980). 1
Volume 59
Number 7
Julv 1982
605
