Most formal definitions characterize explanation as a statement that makes something comprehensible by describing the relevant structure or operation or circumstances. Predominantly, explanation is seen as a tool for describing relevant phenomena, developing students' logical thinking, and guiding students by inductive judgement to generalising. It leads to clarifying interrelations, demonstrating and justifying (Skalková 1999:172). Mayes (2006) argues that explanation goes beyond mere description. Accordingly, a key aspect of explanation is the emphasis on why things happen. In other words, one can think of explanation as an attempt to identify the cause of something. Fairhurst (1981) contextualized explanation in term of requiring something to be explained (the phenomenon that needs to be explained), an explainer (the provider of the explanation) and the explainee (the recipient of the explanation). In this context, Metcalf and Cruickshank (1991) argued that the role of an explanation is to make some concept, procedure or rule plain and comprehensible. Brown and Armstrong (1984) operationally defined explanation as an attempt to provide understanding of a problem to others. This definition strengthens the view of Perrott (1982) who argued that a clear explanation depends on (a) identification of the elements to be related to, for example objects, events, processes and generalisation, and (b), identifying the relationship between them, for example casual, justifying and interpreting. Horwood (2006) on the other hand provides a distinction between explanation and description. According to Horwood (2006), description is purely informational, and the bits of information are isolated from any network of relatedness. In this context, an explanation is given when connections are drawn between and among pieces of information. Furthering this view, Hargie and Dickson (2003) argue that the act of explaining is essentially the same act of describing, instructing or giving of information.