Learning to Use Formulas and Variables for Constructing Computer Models in Lower Secondary Physics Education

In physics education, models of modelling almost always contain a mathematization phase that links the real world with a mathematical representation for the purpose of describing, explaining, or predicting the phenomenon of interest. Mathematization often means the algebraization of a model of the real world in the form of an equation or formula. Success of students in modelling activities of this type depends on how well the students know what a variable and a formula are. This algebraic competency cannot be taken for granted: research has shown that students, both at lower and upper secondary level, have difficulties in selecting, using, and defining relevant variables and relating them algebraically. We argue that these difficulties ask for actions to let students develop the mathematical competency by explicit teaching the concepts and usage of variables and formulas. We discuss the design of a modelling learning path for lower secondary physics that incorporates a partial learning path with a focus on variables and formulas. In this modelling learning part, emphasis is on modelling with computers, in particular on system dynamics-based graphical modelling, because it enables students to study dynamic physical processes from a general point of view, allows treatment of subjects that are more realistic than usual in textbooks, enriches the students’ understanding of the notions of variable and formula, and gives them the opportunity to do what professional modellers do nowadays. We argue that graphical modelling can help lower secondary students develop understanding of the notions of variable and formula.