2014 Volume 54 Issue 3 Pages 403-417
To investigate students’ understanding of ‘buoyancy’, we conducted two research studies from grade seven to university students. The purpose of the first research study (I) was to examine whether introducing the concept of water pressure to students at lower secondary level would affect their understanding about buoyancy. The second research study (II) was conducted for the purpose of investigating the students’ recognition of buoyancy in objects moving in water; one was coming up to the surface and the other was sinking in the water. We also focused on their recognition of buoyancy with regard to ‘the objects above the water and on the bottom in the water’.
As a result of research study I, the following two points were revealed.
(1) The students who understand the feature of water pressure tend to have two images of buoyant force; the deeper the object in the water, the larger the force with which it is buoyed up; actually the buoyant force remains constant whether in shallow or deep water.
(2) On the other hand, the students who did not understand the feature of water pressure had three images of buoyant force; two of three were same mentioned above, in addition, the shallower in the water, the larger the force with which the object was buoyed up. The number of students who gave these three images was the same.
As a result of research study II, the following two points were revealed.
(1) Some students who had not learned about buoyancy could answer that buoyant force acts on static objects hanged by strings in the water. However, they could not point out that buoyant force acts on the floating or sinking object in the water.
(2) The students who have already learned about buoyancy did not have the misunderstandings mentioned above.However most of them thought an equal buoyant force acted on the object both wholly and partly immersed in water.
Moreover, we have suggested the implication of teaching method of buoyancy for grade seven students.
