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Asia-Pacific Forum on Science Learning and Teaching, Volume 7, Issue 1, Article 4 (June, 2006) Muammer ÇALIK , Alipaşa AYAS and Richard K. COLL A constructivist-based model for the teaching of dissolution of gas in a liquid
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Asia-Pacific Forum on Science Learning and Teaching, Volume 7, Issue 1, Article 4 (June, 2006) Muammer ÇALIK , Alipaşa AYAS and Richard K. COLL A constructivist-based model for the teaching of dissolution of gas in a liquid
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Eliciting students’ pre-existing ideas
Before the enactment of the activity, all students are divided into groups of four students. The teacher then asks students about their pre-existing ideas in an attempt to engage them with the task; using prompt questions such as: “How does the dissolution of gas change with pressure? Please explain your reasons”.
In the next step, the activity is explained to each student so that the students can gain experience in following the directions. The teacher observes students’ activities and encourages them to discuss the topics within their group, helping them to explore their understanding of the topic. Also, at this point the teacher tries to help students clarify points, but does not give any clues. After the activity, the teacher asks the students to answer questions that are presented in activity paper, and defend their answers within their groups; in other words they are asked to explain their answers and reasoning to their peers. The questions provided used are: “After doing the second step, what did you observe? Please explain”, “After doing the third step, what did you observe? Please explain”, “Please compare the results of the fourth step with that of the second step?”, “Taking into account the experiences you acquired as a result of activity, please explain the effect of pressure to the dissolution of a gas into water?”
In this evaluation step, the students should by now understand the target concept. However, if students do not, teachers should verify the knowledge domain the students acquire. In this case, for the concept under investigation, the teacher needs to point out that there is a steady increase between dissolution of a gas into liquid and external pressure, that is, if pressure increases, the dissolution of a gas into water also will increase; if it decreases, its dissolution decreases as well.
In this step, it is intended that the students try to apply their experience learned to another different situation, in order to reinforce their new knowledge. Likewise, they also may be able to make relationships between these rather contrived examples, and their daily life. In case of the above concept, students are asked to respond to the following questions: “When a diver dives into the sea, if he or she tries to reach the surface too rapidly, he or she is exposed to a kind of paralysis. Please explain this process by looking at the dissolution of N2 gas in blood”, “When you open a bottle of cola, what happens?” Finally here, in order to explore students’ understanding more deeply the teacher requires them to prepare a composition as to what they felt they learned during these activities. As a result, students can engage in some self-assessment, in order to aid their conceptual understanding. However, in our experience with this sort of self-assessment exercise, students are often reluctant to write down a composition. Therefore, we devised a kind of self-assessment form drawing on the worm of Çepni (2006). When we exploit this, students tend to fill the form easily and seem to enhance their enthusiasm. The form is in the following:
Please select the choice that reflects your self-assessment and write down the concepts you think you have learned and/or the concepts you think you have not learned:
(a) I learned the concepts involved in this activity
(b) I did not learn the concepts involved in this activity
(c) I need to revise them
The concepts I learned: ...............................................................................................
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The concepts I did not learn: .....................................................................................
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Teaching science in many developing countries, or in poorly resourced schools in more developed countries, is often problematic because of lack of teaching facilities or equipment, such as laboratory equipment and technological support such as computer networks (Ayas, Çepni & Akdeniz, 1993). The activity presented here, based on recommendations from the science education literature, and the authors own classroom experiences does not require advanced equipment, and may prove a useful tool and teaching approach for the teaching and learning of the dissolution of a gas into liquid. The present study shows how to use this activity step by step, and is designed based on students’ preconceptions. Teachers are often aware of student alternative conceptions, but not sure how to tackle them. Likewise, administering similar activities may foster better learning. These activities have the benefit of being simple to design and implement, and also help address problems associated with a ‘crowded-curriculum’. Hence, the activity presented here is not only time-efficient but also can be administered easily.
Copyright (C) 2006 HKIEd APFSLT. Volume 7, Issue 1, Article 4 (June, 2006). All Rights Reserved
