Teaching floating and sinking concepts with different methods and techniques based on the 5E instructional model

The purpose of this study was to investigate the influences of the prepared instructional material based on the 5E instructional model combined with CCT, CC, animations, worksheets and POE on changing alternative concepts of students about floating and sinking concepts.

Quantitative analyses were done in order to find whether there is a significant difference between the EG and the CG pretest, posttest and delayed posttest results. As seen from Table IV, there is no significant difference between the EG and the CG according to pretest results. Average order of the EG and the CG were closer to each other [U= 276.000, p>0, 05]. This shows that the EG and CG has similar backgrounds on floating and sinking concepts. After the implementation of the material, when the posttest results were examined, significant difference was found in favor of the EG [U= 128.500, p<0.05]. This means that the material based on the 5E instructional model enriched with different teaching methods and techniques like POE, worksheets, CCT, CC and animation activities has a more positive effect on concept learning of floating and sinking concepts than the existing material based on the 5E instructional model implemented by the Ministry of Education. Also, when the delayed posttest results were examined, a significant difference was seen in favor of the EG [U= 73.500, p<0.05]. Using different teaching methods and techniques together in an instruction is more effective than traditional learning in removing students’ alternative conceptions (Reid et al., 2003; Havu-Nuutinen, 2005; Hardy et al., 2006; İpek & Çalık, 2008; Yin et al., 2008; Özmen et al., 2009). It could be concluded that using instructional material enriched by different teaching methods and techniques has a positive influence on the permanence of learning.

When the results of Wilcoxon signed rank test for the CG are examined, it is seen that there is no significant difference in favor of the pretest, posttest and delayed posttest results for the CG. When Table VII is examined, it has seen that 10 students’ pretest scores are higher than their posttest scores, and 10 students’ posttest scores are higher than their pretest scores in the CG. However, when results of the EG are examined it is seen that there is a significant difference in favor of posttest results for the EG. When Table IX is examined, 3 students’ pretest scores are higher than their posttest scores in the EG. Twenty-one students’ posttest scores are higher than their pretest scores. Since the posttest results of the EG are better than the CG, we could conclude that educational materials have an important effect on the EG students’ conceptual development about floating and sinking more than the existing material in the textbooks. In other words, it can be said that results of Wilcoxon signed ranked test is consistent with the result of Mann Whitney U test. Also, when the delayed posttest results for the EG and the CG students were compared, students in the EG perform more permanent learning than students in the CG.

Figure 1, 2 and 3 show that students in the EG removed their alternative conceptions and most of them moved to the CC-CR category in the delayed posttest. But not many of the CG students moved to the CC-CR category in delayed posttest. This also shows the effect of instructional material embedded with different teaching techniques through the existing one (Çalık, 2006; Özmen et al., 2009).

Figure 1, 2 and 3 show that most of the students in the CG have not moved their alternative concepts in the posttest, although the EG students moved their alternative concepts in the posttest.

From these findings, we can conclude that instructional materials enriched with different techniques could be effective in removing alternative conceptions and providing conceptual change more than the existing material. Although we used the 5E instructional model enriched with different teaching methods and techniques for the EG, we were not fully successful in removing all of the alternative concepts for all students (Çepni et al., 2006). For example, students in both the EG and CG could not remove their alternative conceptions like “objects inside of water are sunk, because floating means to be above of water,” and “heavy objects always sink.” There are well known reasons for not removing alternative conceptions fully. Concepts could be too abstract for the level of students (Başer & Çataloğlu, 2005), the nature of the concept is resistant to change (Fisher, 1985; Çalık, 2006) and the concept has a hierarchical structure.

Although every teaching methods and technique is useful in teaching and learning science, each one has some defects (Carlton, 1999; Keleş & Çepni, 2006). Using a single teaching methods and technique could not always provide conceptual change if students alternative conceptions were resistant to change (Keleş & Çepni, 2006). We used the 5E instructional model enriched with different teaching methods and techniques to overcome these weaknesses. We were successful to some extent in removing alternative conceptions in the EG in comparison with the CG. We can conclude that using different teaching methods and techniques together has a positive influence in removing some alternative conceptions.

Students sometimes have problems in constructing abstract and hierarchical concepts in their minds because it is difficult to know sub-concepts, which will build a base on the related concept, and to build relationships between the concepts and to understand the nature of an abstract concept (Rowell & Dawson, 1977; Sere, 1982; Snir, 1991; Macaroğlu Akgül & Şentürk, 2001; She, 2002; Grotzer, 2003; Kawasaki et al., 2004; She, 2005; Özsevgeç & Çepni, 2006). To learn floating and sinking concepts, at first students should construct the concept of density in their minds. Before understanding the density concept, students have to construct the particular structure of the subject (Strauss et al., 1983; Grotzer, 2003).

Also, it is known that perfect learning sometimes does not occur although a perfect teaching has been executed (Bodner, 1990), as every student perceives in a different way. Although the material was very effective for some of the students to remove their alternative conceptions, it was ineffective in removing some of them (Thorley, 1990; Duit & Treagust, 2003). These conceptions are called hardcore in the related literature. Aypay, Erdoğan and Sözer (2007) suggest that the teacher-centered instruction model should be tried to remove the hardcore alternative conceptions because maybe the difficulty of removing the alternative conception comes from the nature of the concept and Turkish students were familiar with teacher-centered instruction.

Therefore, to have efficient results in conceptual change studies, it is becoming important to use different teaching and learning activities and presenting alternative teaching materials.