Prospective physics teachers’ level of understanding energy, power and force concepts

Even though it has been known only as a physics subject, the concept of energy has an interdisciplinary background and it has been subjected to lots of studies because of its complex nature. Boyes and Stanisstreet (1990), Domenech et al. (2007) and Trumper (1998) reported that students mentioned the energy as a difficult concept to learn. Some other researchers (e.g. Solomon, 1983; Warren, 1983; Watts, 1983) studied the difficulties of teaching about the concept of energy. The difficulties associate with teaching and learning these concepts oriented some researchers to devise effective approaches to teaching.(e.g. Brook & Wells, 1988; Kirkwood & Carr, 1988; 1989; Trumper, 1990a; 1990b; 1991; Huis & Berg, 1993; Gürdal et al., 1998; Heuvelen & Zou, 2001; Fry et.al., 2003; Mutimucuio, 2003; Aydın & Balım, 2005; Tsagliotis, 2005; Papadouris & Constantinou, 2006). For teaching the concepts of energy, some approaches were put forward including, “Abstract Picture Language” (Fry et al., 2003), “Multiple Representations Approach” (Heuvelen & Zou, 2001; Mutimucuio, 2003), “A Systems Approach” (Huis & Berg, 1993).

In spite of the existence of such different approaches, a work concept-grounded approach has been suggested and most adopted for teaching the concepts of energy (Warren, 1986; Küçük et al., 2005; Kurnaz, 2007). When one realizes the associations between work, distance and force concepts, then it is obviously meaningful that to a large extent learning the concept of energy depends on the force concept, which is one of the principal concepts of physics. Certain studies focusing on this relationship determined that students confuse these concepts with each other and could not state the difference between them (Duit, 1984; Goldring & Osborne, 1994; Küçük et al., 2005; Ünal Çoban et al., 2007). Additionally, it was determined that this confusion obstructs students ability to develop alternative ideas related to the concept of energy and truly understand the conceptual nature of it (Duit, 1984; Goldring & Osborne, 1994; Trumper, 1998; Gürdal et al, 1999; Kurnaz, 2007; Küçük et al., 2005; Ünal Çoban et al., 2007). Whereas, according to Domenech et al. (2007), the basic barrier for students to perceive energy arises because they do not know how to define energy. The studies about the issue have shown that students tried to define energy based on only a single discipline, they could not associate meanings of energy in different disciplines and they had difficulties understanding energy related terms like power and force (Hırça et al., 2008; Kurnaz, 2007; Küçük et al., 2005).

It is known that determining students’ probable weaknesses and mistakes about conceptual perceptions in advance is helpful in terms of providing students and teachers with necessary information to solve and to develop solution strategies for scientific or daily life problems related to these concepts (Küçük et al., 2005; Trumper, 1990a). Therefore, in order to tackle probable problems faced while teaching the closely interrelated terms, power, force and energy, the first thing one should determine is how much students know about these concepts and to what extent they can differentiate between them. Most of the studies about this issue were carried out at the primary school level. In this context, researchers have investigated the students’ levels of understanding of energy and related concepts. Watts (1983) carried out a study with primary school students of different grades; Duit’s study examined (1984) primary and secondary school students (6^th to 10^th grades) from different countries; Goldring and Osborne (1994) studied 6^th graders; Küçük et al. (2005) studied 7^th grades; Ünal Çoban et al. (2007) and Hırça et al. (2008) studied 8^th graders. The striking findings of the research related to students’ alternative conceptions and learning difficulties are presented below.

Alternative conceptions	Only living organisms have energy.	Watts (1983), Ünal Çoban et al. (2007) and Hırça et al. (2008)
	Non-living things do not have energy because they do not move.
	Moving/activity means energy.	Watts (1983)
	Energy can be generated.	Watts (1983)
	Energy is a kind of matter.	Küçük et al. (2005)
	Energy can not be stored in objects such as oil, coal and books. They have energy when they burn or move.	Watts (1983) and Küçük et al. (2005)
Learning difficulties	Students do not have proper information about energy forms.	Watts (1983), Ünal Çoban et al. (2007) and Hırça et al. (2008)
	Students confound the concept of energy with force, power and electric concepts.	Küçük et al. (2005)
	Students mostly define energy in colloquial terms rather than in a scientifically meaningful way.	Duit (1984)
	Students can not explain the meaning of energy conservation.	Duit (1984), Goldring & Osborne (1994)
	Students generally fail to determine the unit of energy or power.	Goldring & Osborne (1994)

There have been not enough studies examining students’ perception of energy and related terms with university students. Thus, this study was aimed at determining prospective physics teachers’ level of understanding of energy, power and force concepts and how these concepts are primarily associated in relation to physics. As a result, it is believed that instructors may use students’ alternative frameworks related to energy, power and force to construct a meaningful understanding of students in a scientific manner.