Examining preservice science teachers’ skills of formulating hypotheses and identifying variables

After the study was completed, preservice science teachers’ skills of formulating a hypothesis and identifying variables were investigated in detail. The study also examined preservice science teachers’ preferences on hypothesis structure (H0, H1-non-directional and H1-directional) while formulating a hypothesis. Additionally, the types of mistakes made by preservice science teachers while identifying variables were examined, along with what they believed caused their mistakes. In addition, in this study were what causes their mistakes in identifying variables and formulating a hypothesis according to preservice science teachers. The results obtained for each sub-problem are as follows:

1. The study examined preservice science teachers’ skill formulating hypotheses and identifying variables in Scenario-1 and Scenario-2. The study results show that preservice science teachers’ skill formulating hypotheses correctly was quite poor. Those results are supported by observation findings; three preservice teachers (PST-7, PST-8 & PST-9) selected among preservice teachers with poor hypothesis formulating skills failed to formulate their hypotheses correctly according to Scenario-3 and Scenario-4 in a real classroom environment. Scenario-1 and Scenario-2 were used in this study and other studies for the purpose of assessing science process skills of both teachers and preservice teachers. The same scenarios were used by Aydoğdu, Erkol and Erten (2013) to evaluated elementary school teachers, as well as by others (Aydoğdu, Yıldız, Akpınar & Ergin, 2007; Bağcı-Kılıç, Yardımcı and Metin, 2009) to evaluate preservice science teachers. All of these studies found low levels of hypothesis-forming skills. Other studies that just identified the skill of preservice science teachers to formulate a hypothesis found that their hypothesis formulating skills were poor (Saka, 2012; Çelik & Özbek, 2013). Formulating hypotheses depends on perception and interpretation of abstract concepts (Taşkın and Koray, 2006: 99). This situation may be one of the reasons for deficiency of formulating hypothesis of preservice science teachers. The reason for this deficiency in formulating hypothesis of preservice science teachers should be analyzed further in future studies. The study also examined preservice science teachers’ identifying and controlling variables in a given scenario. The study results show that preservice science teachers’ skill in this area was quite poor. The same scenarios (Scenario-1 and Scenario-2) were used by Aydoğdu, Erkol and Erten (2013) for elementary class teachers and the study results indicated that the skills of elementary class teachers were poor. In the studies where the same scenarios were used again to evaluated preservice teachers (Aydoğdu, Yıldız, Akpınar & Ergin, 2007; Bağcı-Kılıç, Yardımcı & Metin, 2009), it was found that their skills were quite poor. Furthermore, the same scenarios were used for preservice elementary class teachers, and the study results indicated low level skills (Aydoğdu & Buldur, 2013; Bağcı-Kılıç, Yardımcı & Metin, 2009). Many other studies have found that preservice science teachers lack the skill to identify and control variables (Ateş, 2005; Saka, 2012; Çelik & Özbek, 2013). Similar results were found in studies conducted at the high school level. These study results demonstrated that high school students’ skills of identifying and controlling variables were low (Beaumont-Walters & Soyibo, 2001). In their study, Aziz and Md Zain (2010) compared the science process skills in 10th, 11th, and 12th grade students’ physics books in Yemeni schools. Their studies’ results showed that physics books included little on formulating hypotheses or identifying variables. This study, along with other study results, indicates that generally, preservice science teachers’ skills of formulating hypotheses and identifying and controlling variables were low. Different activities to improve preservice science teachers’ science process skills should be administered. Ünal-Çoban (2013) revealed that the curricula should be supported by practice in order to have a significant gain in science process skills. Other studies found that laboratory work improved students’ science process skills (Tamir, Doran & Chye, 1992; Germann, Aram, Burke, 1996; Zuzovsky, 1999; Hofstein &Lunetta, 2003). For this purpose it is very important that students should study in laboratories until the end of improving their science process skills.

2. The preservice science teachers who formed a correct hypothesis used both H1-one-directional and H1-non-directional structure. The data from observations also confirmed that observed pre-service science teachers did not formulate a single Ho hypothesis. Preservice science teachers used a H1-non-directional hypothesis because they thought the dependent variable may change with the independent variable but could not guess in which direction (linear or reverse) this change would occur. Abruscato (2000:46) says that the hypothesis to be formulated should depend on observations or arguments. Since students make many observations in daily life, they actually have pre-understanding about most issues to be researched. For example, students came across many times in their daily lives that a cube of sugar dissolved faster in hot water than in cold water. Students may then formulate the hypothesis that all substances that can dissolve more quickly in hot water than they do in cold water. A hypothesis may also be produced from an argument at the same time. For example, if a glass jar is put over a burning candle, the candle will be extinguished in a short time. One may formulate the argument on the basis of this observation that the candle was extinguished due to lack of oxygen. Later the students may formulate the hypothesis that the candle surrounded with glass jar will be extinguished when the oxygen is the jar is used. Similarly, Ateş (2005) specifies that creation of conceptual knowledge by individuals depend on their formulating hypotheses and testing them. Furthermore, it is necessary to withdraw the first hypothesis and formulate a new hypothesis to test if they encounter any disconformity between the initial expected results and the experimental results. In this study, preservice science teachers generally tend to formulate alternative hypotheses, probably owing to observations and arguments they encounter in their daily lives. Preservice science teachers may be inclined toward alternative hypotheses when they consider that an independent variable may have effect on a dependent variable based on those observations and arguments. In addition to this, preservice teachers may also think the change in the independent variable may lead to change in dependent variable while they are formulating alternative hypothesis. Why preservice science teachers prefer H1-non-directional hypotheses should be studied in another study in detail.

3. The types of mistakes preservice science teachers made was examined in detail. In particular, preservice science teachers wrote off-topic variables instead of the relevant variable, wrote more than one variable, or mistook one variable for another variable. The data from observations also confirmed that pre-service science teachers confused the independent variable with dependent variable. During observation, seven pre-service science teachers did not indicate any control variables while doing a controlled experiment. Other studies have identified that variables are taught similar to statistics in science teaching as dependent, independent and controlled variables (Bağcı-Kılıç, Yardımcı & Metin, 2009), and that this terminology might be confusing (Ateş, 2005; Bağcı-Kılıç, Yardımcı & Metin, 2009). For this reason, some researchers have stated that its better to use “observed variable” instead of “dependent variable,” “changed variable” instead of “independent variable” and “controlled or whose effect can be controlled variable” instead of “control variable” (Bağcı-Kılıç, Yardımcı & Metin, 2009).

4. This study also interviewed 58 preservice science teachers who had identified both the hypothesis and the variables incorrectly. They gave the following reasons for their poor performance: their courses do not teach science process skills, experiments done in the laboratories do not include enough science process skills, unaware of the importance of science process skills, the traditional teaching methods used in their courses and instructors did not have enough science process skills. These findings indicate that preservice science teachers accept their mistakes. Moreover, the excuses provided by the preservice science teachers are attention drawing, but not surprising because theory is not really put into practice. Although pre-service science teachers should acquire science process skills through open-ended experiments which include those skills, contemporary methods of instruction, and well-equipped instructors, who have already developed science process skills and are able to transfer these to their students through science laboratory activities (Nantarat Kruea-In and Orawan Thongperm, 2014), it is not the case. Therefore, it is necessary to redesign science teaching in a way that it helps preservice science teachers develop those skills (Huppert, Lomask & Lazarowitz, 2002; Saat, 2004). In science teaching, laboratories have an important effect (Lawson, 1995). Moreover, laboratories can greatly contribute to the acquisition of science process skills (Renner, Abraham, Birnie, 1985; Bryant & Edmunt, 1987; Germann, Aram & Burke, 1996; Tamir, 1997; Zuzovsky, 1999). However the experimental techniques used in the laboratories are significant as well. Many studies have found that open-ended experiments are more effective than closed-ended experiments in terms of science process skills (Renner, 1986; Tsai, 1999; Reid & Shah, 2006; Aktamış, 2007; Aydoğdu, 2009; Özgelen, Yılmaz-Tüzün & Hanuscin, 2012). Because close-ended experiments have a limited role in teaching science process skills, open-ended (i.e. inquiry based experiments) experiments, which help students to acquire science process skills, are preferred. Open-ended experiments will also help students be in the center of the teaching-learning process. Other courses should also be taught with methods that enable students to more actively develop science process skills. Some students might not attach any meaning to those skills or those skills do not make any sense to them and hence, they might not give importance to learn those skills. This finding is also not surprising because one can meaningfully learn unless s/he has an already cognitive structure with which the new information can be associated. In other words, learning will not be meaningful if a learner lacks that cognitive structure (Ivie, 1998).