Representations of scientific concepts are important tools for creating understanding of science. In connection with the scientific concepts mentioned in textbooks it is common to use many other forms of representation to clarify them. In this study, we focus on physics textbooks for lower secondary school and more specifically, how the concept of pressure is presented. The examination of the textbooks will be divided into in two parts. In the first part we study the representations that occur from a quantitative perspective. The representations will be sorted into three main categories (Liu & Khine, 2016). For each category there are sub-categories. In the second part of the study, representations will be studied from a qualitative perspective and described with respect to how they are used and interconnected in the textbooks. In this second part, the representations are analysed and sorted into four main categories (Slough, McTigue, Suyeon, & Jennings, 2010). Preliminary results from the first part of the study show that textual representations dominate together with graphical representations in all textbooks, while the mathematical representations only occur occasionally. The second part of the study is on-going and preliminary results will be presented and discussed, together with implication for teaching.