. By Chung Chieh (e-mail), Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L3G1

5. Demonstrations

One of the early intentions of Computer Assisted Chemistry Tutorials (CACT) was to provide computer Demonstrations, which could be simulations of chemical principles, visulization of chemical concepts, demonstrations of experiments, and illustrations of theories.

For simplicity, demonstrations were called Demos in the DOS version of CACT. We implemented selected topics, each had a Demo as an enhancement of our teaching. We did not intend to cover all the lecture material or course content.

5.1 Demos

Demonstrations of term I
Battery Galvanic cell simulation
BondEL Chemical bond length and energy
Conventn Conventions used in CACT
EMWave Electromagnetic radiation wave
Gaslaws Gaslaws
HBond Electron density of H-H bonds
Hybrid Hybrid atomic orbitals
KinetGas Gas kinetics
Limitn Limiting and excess reagents
Molecule User controlled molecular display
Orbital Electron density of atomic orbital
PeriodTb Electronic periodic tabel
PiBond Electronic density of pi-bonding
QuantNum Quantum numbers
Spectrum Simulation of spectrum
TVP The ideal gas law
VSEPR VSEPR and molecular shapes
The personal computers' ability to display vivid graphics in color has attracted many educators to write programs to demonstrate (Demos for short) chemical concepts and theories. We have also written a number such programs, which were organized for students to use in the DOS version of CACT, first for students in the Chemistry programs, and then for all freshman chemistry students.

The Demos used for the first term are listed in the Table here. Most Demos were written by me, in the Quick Basic language. The Demos were organized using the Menu like that shown on the right. Each Demo had its own Instruction and Dialogue. Few Demos were adopted from other sources, because of copyright and difficulties in their integration into CACT. Approximately the same number of Demos were written for the second term freshman chemistry, but for brevity, they are not given here.

The drawback of the DOS version of CACT was that the Demo and its Instruction could not appear on the same screen. This created some inconvenience for students, because they had to copy down the points in order to fully realize the benefit of the Demo. Having the Instruction and its Demo on the same screen would have been more convenient.

5.2 Loss of Demos in the Internet CACT

Because the Demos are written in Quiz Basic, they cannot be directly implemented in the Internet documents. If they were hyper-linked on the pages and the user clicks them, the users' computers will ask if they want to download them onto their computers. Such an arrangement is not practical for freshmen taking chemistry, and the Demos were not included in the Internet CACT. Thus, the Demos ceased to function in the Internet CACT, due to the change in technology. However, the Demos can still be used during lectures in classrooms with computer display facilities.

It is possible to rewrite the Demos in Java applets or Java scripts. However, due to time constraints, these have yet to be done.

5.3 Advantages of Internet CACT

Despite the loss of the Demos, making CACT available on the Internet offers many advantages over the DOS CACT: Because computers are close to each other in our computer labs, we have not included any sound tracks, nor have we included any video demonstrations. These require much more effort to implement.

Key word searching is very useful for active learners, but most students are passive learners.