Implications of Data-logging on A.L. Physics Experiments: A Preliminary Study

Asia-Pacific Forum on Science Learning and Teaching, Volume 1, Issue 2, Article 5 (Dec., 2000)
Pun-hon NG and Yau-yuen YEUNG
Implications of Data-logging on A.L. Physics Experiments: A Preliminary Study

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Implications and Conclusion
All secondary schools will be equipped with data-loggers in the coming two years. There should be no doubt that this IT tool can increase the scope of physics experiments. It can measure something that cannot be measured before. However, our focus should be not only on more data recording experiments, but also on collecting data for more investigative activities.

The data collected in this study is quite preliminary but it can still give some insight about the adaptation of data-logging into the teaching and learning of physics.

The approach on how to guide the students to become familiar with the software needs further investigation. In this study, a paragraph supplemented with diagram on how to use the software to record data was given on every worksheet. One student commented that: "The guidelines are useful in doing the first experiment but they become boring when similar description is found in every experiment." Students need to invest a certain amount of time to gain familiarity and confidence in using the software. Rogers (1997) suggested a progression of sophistication approach in which the students are first asked to describe a graph obtained from a very simple data-logging activity. Then the progression moves to a more quantitative approach to measure changes and gradients. At the highest level, groups of observations are linked and relationships are explored. In this approach, teachers don't need to describe and explain too much. They just give some very brief introduction on how to log and present data. They will guide the students to finish the tasks simply by providing some prompting questions.

Some students expressed that observing a data recording process was boring. For this risk to be avoided, there is a clear need for the students' activities to be carefully structured (Newton, 1997). They should be encouraged to develop the habit to think and comment about their data as they appear on the screen, by providing some prompting strategies or activities.

Two students stated that they preferred to use CRO to observe a varying signal rather than using data-logger because the selection of a correct voltage gain is a very common topic in both written and practical examinations. Actually, auto-ranging CRO's are quite common in industrial applications as their prices are decreasing. There is also a trend to use fast interfacing card (with similar function as a data-logger) to replace the CRO. As data-logger is becoming more popular in physics experiments, some 'old' apparatus and techniques should be phased out, particularly in the public examinations. There is a similar case known from a data-logging pilot school. The students performed the motion experiments with both the data-logger (because it gave better results) and the ticker-tape (because this was stated in the examination syllabus). This is a waste of time and resources.

Another implication to the public examinations is what skills should be assessed. The proposed Teacher Assessment Scheme (TAS) still focus on the setting up of apparatus and the recording of data. Quite often, a graph is the final output. However in data-logging, it is almost impossible to assess the data recording skill, and the graph is just the starting point rather than the end-product of the whole experiment. Part of the TAS focus should shift from low level skills such as data recording and graph plotting to higher cognitive skills such as setting and testing hypothesis and problem solving by data-logging investigative activities.

Although data-logging can assist investigative activities, students in this study did not perform well in this aspect. This can be reflected from the interview and the worksheets they have handed in. It is not a surprise to have such result as investigative approach is very uncommon in current ways of teaching physics in Hong Kong. The authors predict that some teachers will definitely have similar problem as the students. There is an urgent need for in-service training of physics teachers on the effective use of data-loggers. Similar findings were obtained from another study by the authors (Yeung & Ng, 2000). Among all the IT tools that can support physics teaching, data-logger was rated as the highest in the need of more in-depth training by a group of physics teachers attending an IT workshop.