Virtual chemistry lab for acid-base titration
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UnderstandingThe students agreed that both the information part and the experiment part helped understand the concepts of acid and base and the procedure of titration. They pointed out that the explanation connected to everyday life was very interesting and helpful because it help them not only transfer our everyday life to the science subject but also grasp the concepts of acid and base. Especially, when they went through the classification of everyday things into acid and base and the diagram of pH values of them, they nodded and looked at the web page with interest. However, when they encountered the pure scientific explanations and terms, which one of the students called ătechnical stuff,ä they frowned and their reading speeds were definitely reduced. Without the context of real life, it was difficult to motivate the general users to study further.
The students also mentioned that the organization of the information helped their understanding. Not only the connection to everyday life, but also the organization of the information page -- step by step explanation, the visualized explanation with equations and figures, and relevant examples -- helped them understand the concepts. However, when interviewing, one of the students complained that some parts were difficult to understand and she felt she needed more detailed explanation about the concepts to understand. For example, there is an equation about pH value. ăpH = -log [H+].ä When she saw the equation, she didnât remember the meaning of ălog,ä and wanted some examples of it.
When constructing the information part, I paid a lot of attention to make the explanation more understandable and easier than explanations from other textbooks or web sites and add more graphics and examples for better understanding. However, because it was displayed on the web, I tried to limit the length of the explanation to avoid the visitors to get discouraged by the lengthy illustration and move around to other ăfunä sites. Even though it seemed easier than other explanations, it was still difficult and not enough for the Internet users. The question is how to comprise between more lengthy explanation and more visitors.
Interface
It was true that the longer the lines of the program are, the more positive reaction you get. The favorite part of the simulation program was the titration step. All of the students liked the changes in color, pH, and volume of mixed solutions during titrating an acid and a base (Maybe they didnât expect to see that kind of change from a mere graduate studentâs program). However, some students were not able to proceed the titrating procedure because the manual of this part did not provide enough information about the technique of determining the equivalence point (end point). So, it was thought necessary to add more information about it.
Another feature of the program the students didnât feel comfortable with, although they liked it, was choosing chemicals for titration among many kinds of solutions with various concentrations and volumes. This discomfort was caused when they realized they need thorough understanding about titration and careful reflection. They were usually spoon-fed even during lab hours and have used one set of given solutions with determined concentration and volume. As a result, they were not familiar with selecting or designing their own experiment. This is not regarded a problem from the interface of the simulation program. Rather, it is a problem caused by not inquiry-based lab environment or by the teacherâs emphasis only on experimental manipulation skills instead of on the principles and methods of the experiment.
When designing the simulation program, I tried to apply easy and conventional interface and most of the simulation was well understood by the users. However, there were some difficulties proceeding the virtual lab.
One common problem was the inconvenience using the userâs guide while doing the virtual experiment. The location of the explanation was outside of the simulation program and the users had to scroll up and down the web page to view the manual. A student even didnât go back and try to understand the interface of the program. This inconvenience was caused because I wanted to reduce the loading time of the Java applet. Usually Java applets take a long time to download with modem connections, so I figured that it would make the users get bored with waiting if the explanation were put in the simulation itself to make the file size a lot bigger. To minimize the loading time, I tried to make the size of the simulation program as small as possible and the manual of the program was separated from the simulation program.
Another technological problem is caused by display setting. In Java applets, the size should be provided with pixels not with the percentage of the screen. Also, to view the full image of the program in the lowest resolution setting, it was necessary to fix the image size of the applet to smaller than 640X480 pixels. This caused a problem with 1024X768 setting on 17ä monitor, which was the display setting used for the evaluation. The image of the program was small and the students felt uncomfortable reading small fonts and graphics of the program.
Comparison
In the comparison with actual titration experiment, two students definitely preferred the virtual experiment and only one student preferred the actual experiment because it is hands-on and you can see the actual things and events in front of your eyes. However, she also pointed out the advantages of the simulation program like other students; it was easier, quicker than the actual and selection of the solutions and repetition of the process was possible. Usually a chemistry lab takes more than two hours for acid-base titration, but the virtual chemistry lab allowed the experiment to be finished within 40 minutes. The simulation program itself only took the students 15 to 20 minutes (Here, I counted the time for reading the userâs guide for the simulation program). More importantly, when the students performed the virtual lab, they could see an in-depth explanation about background information of the lab and the lab procedure. They said that when they carried out an actual chemistry experiment, they didnât really pay attention to the principle of the lab nor to the reason why they used specific chemicals. One essential reason for letting students carry out an experiment is that help them understand the major science concepts more effectively as well as help them acquire experimental skills. In this sense, the virtual lab attributes the main purpose of chemistry lab more than the actual lab.
In the comparison with other simulation programs, one student compared the program with one of his physiology simulation program. According to him, the physiology program used video clips instead of drawings, and this feature made the user feel like doing a real dissection, in other words, it was more like a real experiment. It is known that some of software for biology and physiology class has a good quality and it shows inside of human body layer by layer using drawings and real video clips, otherwise impossible for students to view the inside up close and personal. I admit that this program does not have that kind of significance and this program does not have high quality video clips. However, in my simulation program, I donât think that it is really necessary to implant a video clip to make it a bigger file. Pictures of a beaker and other equipment will provide more reality, but the simple operation of titration does not seem to require ărealä video clips.
One student compared the program with a similar simulation program that she used in her college chemistry course. She preferred the other simulation program because the display of the program was bigger, and the lab simulation and the manual were not separated. The one she used in her chemistry course was a form of CD-ROM, which can carry many pictures. The display setting in the computer lab was adjusted for the simulation program. These limitations of my program she mentioned were due to the fact that the program is an Internet application. Internet users usually do not change display setting frequently for a better size of one Internet application, and the programming language for Internet application, Java, is one of the slowest programming languages. Even though the programmer cannot set up a display setting for every user, it is possible to combine the simulation program and the manual for the Visual Basic version because it is a downloadable file to local computers.
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