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edited bv
Highlights SUSAN H. HIXSON
National Sctence Foundation Arlington, VA 22230
CURTIS T. SEARS, JR. Georgia State University
Atlanta, GA 30303
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Projects supported by the NSF Division of ~ n d e r ~ r a d u a
t e Cducation An Interactive Multimedia Software Program
for Exploring Electrochemical Cells
Thomas J. Greenbowe Iowa State Jn Yerslly of Sc~ence and Techno
ogy Arnes, IA 50011
Many chemical processes are difficult to communicate ef-
fectively because the concepts require individuals to visu- alize
the movement ofmolecules, ions, or electrons. Herron and Greenbowe
(1) have stressed the importance of in- structors helping students
make connections between three levels of representation:
macroscopic, microscopic, and symbolic. Static diagrams, graphs,
chemical equa- tions, mathematical equations. and chemical symbols
are part of the symbolic ievel of representation. ?:hemistry
demonstrations and laboratory actirities idlow students to directly
observe chemical reactions at the macroscopic level. Amissina
component of instruction is a way to con- vey the m i c r ~ ~ ~ i c
level of representation of a ihemical process. Explaining dynamic
processes of equilibrium re- actions and-oxidation&ductibn
reactions becomes easier when students can observe a computer
animation or simu- lation of these processes.
McPhillen and Greenbowe (2), Lynch and Greenbowe (31, and
Greenbowe and Parker (4) have developed computer animated sequences
and interactive multimedia instruc- tional programs for use in
introductory chemistry. The "Electrochemical Cells Workbench" is
one component of a software package that allows students and
faculty to ex- plore building and testing electrochemical cells.
The "workbench" is a microworld environment simulating a chemistry
laboratory in which a student can perform ex- periments. The
"workbench" section of the program pro- vides students and
instructors the opportunity to manipu-
Figure 1. A computer screen image of the electrochemistry work-
bench showing three aqueous solutions and two beakers.
Figure 2. A computer screen image of the electrochemistry work-
bench showing a voltmeter, metal electrodes, wires, and
saltbridge.
late experimental apparatus, chemicals, and instruments in order
to design and build an experiment. Students use a mouse to
"point-and-drag" objects on the screen that repre- sent beakers,
various metal electrodes, salt bridge, wires, and a voltmeter to
seeup and test an electrochemical cell. For example, when viewing
the screen the student selects three solutions to work with from a
menu of 12 solutions. The solutions appear as labeled reagent
hottles on a shelf. Beakers are moved under the spigots of each
bottle. The spigot from a bottle is opened to allow the solution to
fill one of the beakers. Figure 1 shows a computer screen of the
chemistry workbench with three 1.0 M aqueous solu- tions to choose
from. In this example, the student is choos- ing to work with
aqueous 1.0 M coppedII) nitrate in one beaker and aqueous 1.0 M
zinc nitrate in another beaker.
The menu of aqueous solutions also includes the option of
working with 0.10 M, 0.010 M, and 0.0010 M aqueous solutions.
enabline students to exolore concentration cells and calklations
i&olviug the st equation. Next, the student selects metal
electrodes to lace in the solutions. A menu presents various metal
electiodes to choose from. If a student wants to explore building
an electrochemical cell by placing a zinc metal electrode in
copper(I1) nitrate solu- tion and by placing a copper electrode in
zinc nitrate solu- tion, the program will do so. This is an
important compo- nent of interactive multimedia: the user is
presented with decisions to make just as if he or she were in a
laboratory working with electrochemical cells. The program prompts
students with hints if they are having trouble setting-up a cell,
and there is a help menu also. Figure 2 shows the com- ponents of
an electrochemical cell being assembled. One beaker contains 1.0 M
coppedII) nitrate and a copper elec- trode; a second beaker
contains zinc nitrate and a zinc elec- trode. Avoltmeter, wires,
and a salt bridge are available.
The student moves the wires to connect the electrodes to the
voltmeter. Again, the student must make a decision: which
electrodes should be connected to which terminals.
Volume 71 Number 7 July 1994 555
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Figure 3. Acomputer screen image of a copperlzinccell with a
digital color overlay (right).
A salt-bridge must be inserted connecting the two beakers in
order to complete the circuit. If students connect the wires one
way and obtain a negative voltaze on the voltme- ter, they can
readily change the connemions of the wires to obtain a positive
voltage. When the elec~rochemical cell is assembled, a color
digital photograph ol'a similar electro- chemical cell connected to
a voltmeter is displayed along- side the simulated cell as shown in
Firmre 3.
After assembling an electrochemical cell, the student has the
option of viewing animation sequences on two scales. The first
scale shows an animation of the entire electrochemical cell. The
student observes simultaneous oxidation-reduction reactions
occurring at each electrode, migration of ions in the solutions,
migration of ions within the salt-bridge and at the ends of the
salt-bridge, and di- rection of movement of electrons in the wire.
This view re- inforces the dynamic nature of electrochemistry and
pro- vides students with a representation at the microscopic level.
Figure 4 shows a computer screen of one frame of an animation for a
copper-zinc electrochemical cell. A mouse is used to "click-on"
control panel buttons that pause, move ahead one frame a t a time,
move backwards one frame at a time, repeat, or exit the
animation.
The second scale of animation allows users to click-on areas of
the cell to observe a "zoom view" at the atom or ion level as shown
in Figure 5. Zooming in on the copper elec- trode shows copper(I1)
ions in solution and copper atoms comprising the electrode. As
electrons are shunted down
Figure 4. A computer screen image of a copperlzinc electrochemi-
cal cell.
Figure 5. Acomputer screen image of acopperlzincelectrochemical
cell with zoom, click-touch areas.
the electrode, copperiII) ions move toward the electrode where
they each acquire two electrons. When the electrons are awuired.
the size of the co~~er ( I1 ) ion increases as it becomes a copper
atom and atta%est;the electrode. Com- uuter animation helus make
the connection between the chemical symbols, ci21(aq) + 2 e ->
Cub), and the mi- croscopic level of representation of this
process. Figure 6 illustrates the reduction process occurring at
the cathode. -
A small image of the copper-zinc cell appears in the up- per
right-hand corner with a box around the copper elec- trode to help
students recognize that what they are view- ing is the enlarged
area around the copper electrode. I t also serves to reinforce to
students that other processes are happening simultaneously in the
cell.
While comuuter-animated sequences are fine for simu- lating
dynamic motion of molehes (microscopic repre- sentation), students
need to be able to connect these mod- els with actual chemical
processes. Used by instructors in their lecture presentations, the
animations are most effec- tive when coupled with live
demonstrations of electro- chemical cells. In the laboratory,
students construct sev- eral electrochemical cells using metals,
solutions, a salt bridge, wires, and a voltmeter. Before they
measure the voltage, the students draw a diagram predicting the
loca- tion of the oxidation and reduction processes, the move- ment
of electrons in the wire, migration of ions within and at the ends
of the salt bridge, and the identity of the anode and the cathode.
They check their predictions with the
Figure 6. Azoomed-in image of a representation of a copper elec-
trode functioning as a cathode.
556 Journal of Chemical Education
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computer animation. Of particular interest is the discov- ery by
students that a negative voltage does not indicate that the
electrons and oxidation-reduction process is re- versed.
The results of preliminary studies indicate that the pro- gram
helps students achieve a better conceptual under- standing of the
processes occurring in electrochemical cells. These studies also
indicate that student learning styles play a role in whether or not
students benefit from viewing and working with the animations,
simulations, and instructional modules. The interactive multimedia
program becomes a problem solving tool, a wnceptualizer, and a
tutorial for the student.
Acknowledgement The National Science Foundation Division of
Under-
graduate Education has provided support for this project through
Grant No. DUE 9253985.
Literature Cited 1. Hermn, J. D.; Greenbowe, T. J. J Cham Edue
1986,63. 528. 2. Lynch, M ; Greenbowe,T J. "An InteractiveKineties
Program'.Apaper presented at
the 12th Biennial Conference on Chemical Education, University
ofCalifornia - Davis. Davis. CA, Augvrt 6.1992.
3. McPh3len. M. A ; Greenbowe, T. J. "An Int t tadi~e E l ~ t t
h h m i i i l Cell Programgra.A paper presented at the 12th
Biennial Conference on Chemical Education, Univer- sity of
California-Davis, Davis, CA, Avgvrt 6, 1992.
4. Greenbowe, T J . ; Parlte~ M. M. l l s ing Interactive
Multimedia To Help Students understand f i n p l e a and concepts
of ~ ~ ~ ~ t ~ = h ~ ~ i ~ ~ ~ C ~ I Y S . A~~~~ presolted nf the
American Chemical Society meetin& San Diego, March, 1994.
Science Education Is Focus of New RCS Prosram - - -- -
The recently reestablished State and Lacal Government Affairs
program (SLGA) within the American Chemical Society's Department of
Gavemment Relations and Science Policy will aid ACS members in
pmduetively interacting with their state and local deeisianmakers.
The initial focus of the Proeram will be science education a t the
elementaw and secondary level.
Wide acceptance of the need to reform education in the United
States exists. Efforts by the Nation's governors and recent
congressional passage of legislation supporting the development of
national standards testify to this fact. While the American
Chemical Saiety and many other groups contribute to Congress's
development of federal education policy, much of the reform
activity is centered a t the state and local levels. The SLGA
program will help fill this niche and build on the work underway in
many ACS Local Sections across the country. Through distribution of
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local reform measures, the Pmgram will enable ACS members to become
a force in shaping education reform to the benefit of the sciences.
A Public Affairs Kit, newsletter, and other materials will allow
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State legislatures offer a unique opportunity to affect public
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edueation to environmental protection. Legislators a t the state
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counterparts. Many also hold other full-time jobs, making the
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credibility lacked by groups representing narmwer interests.
In the education area, the Society Committee on Education
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several areas for emphasis: (1) measures dealing with teacher
training and qualifications, (2) account- ability for federal
funds, and (3) programs to attract and retain populations
underrepresented in the sciences. Afive- member Advisory Board
provides strategic direction. The Board includes chemical
professionals from industry, academe (precollege, two-year, and
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To maximize its impact, SLGA has selected 15 target states in
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Jersey, New York, North Carolina, Ohio, Pennsylvania, Texas,
Washington, and Wisconsin. Members may request further assistance
for other states or an additional issues.
While intended far American Chemical Society members, the
SLGAnewsletter also will be useful to others following science
education reform developments. Ta receive the free newsletter and
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SLGAstaff. He i s a t the American Chemical Society, 1155 Sixteenth
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2021872-6206 (fax), or wtg93Bacs.org (Internet). ACS members
requesting informa- tion are asked to identify their Lacal Section
affiliation.
David R. Schleicher Depattment of Government Relations and
Science Policy
American Chemical Society Washington, DC
Volume 71 Number 7 July 1994 557