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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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Activity
To carry out this activity, students conduct the following steps:
- Suck up 10 mL of a carbonate drink such as ‘cola’ using an injector (ensure that there is no air space between the cola and injector).
- Pull the pump of the injector from I to II as indicated in Figure 1.
- During this step, make sure to move the pump of the injector from II to I as indicated in Figure 1.
- Repeat step 2.
Figure 1
As students conduct Step 2, they should observe that there are many bubbles in the injector. From this exercise, they should conclude that as the pressure decreases (as the injector moves from I to II), the bubbles can then be seen by the naked eye. When carrying out Step 3, the student’s should observe that the bubbles, which emerged in the previous step, disappear; in other words, the bubbles cannot be seen easily by the naked eye. From this, they should deduce that the more the external pressure increases, the more gas molecules dissolve in the liquid. By repeating the process in Step 2, the students should again see the effect of the external pressure, and this should help confirm their previous observation and subsequent conclusion.
We now consider how we can adopt this activity based on the four-step 4E constructivist-teaching model (engage, explore, explain, evaluate, see Bodzin, Cates & Price, 2003; Bodzin, Cates, Price & Pratt, 2003), and show how teachers are able to use the activity to enhance student understanding.
Copyright (C) 2006 HKIEd APFSLT. Volume 7, Issue 1, Article 4 (June, 2006). All Rights Reserved.
