In this thesis, I explore the role that visual representations play in the teaching and learning of chemistry, using chemical bonding as a particular case. I do this in a novel way by drawing on a combination of social semiotics and phenomenography. This combination allowed me to explore both the “what” and the “how” of teaching and learning with regards to the visual representations used. And, by exploring the three interconnected dimensions that constitute the phenomenographic concept of the object of learning – the intended, enacted and lived object of learning, I am able to provide a more extensive understanding of the role visual representations play in chemistry education.

The empirical context is the Swedish upper secondary school chemistry classroom. I conducted interviews with teachers and students to explore their views of the role visual representations play in the teaching and learning of chemistry. When observing and recording teachers’ lessons of intermolecular forces I also explored their unpacking of visual representations. 

I found that chemistry teachers do not always explicitly reflect on their use and selection of visual representations. The teachers’ limited reasoning in this regard presents a strong case for increasing the focus on visual communication in chemistry teacher education and in teacher development programmes in order to improve teachers’ visual representational practices. Furthermore, I found that visual representations can be unpacked in five qualitatively different ways when teaching intermolecular forces. These ways of unpacking can be arranged hierarchically, based on their perceived complexity from a student perspective. Two of these ways of unpacking are teacher-centered, whilst the other three are student-centered. The hierarchy suggest that teachers should reason not only about what visual representations they should use, but also how they should unpack them in order to maximise the possibilities for their students’ meaning-making. The analysis of the students’ interviews confirmed that if teachers are going to open up learning possibilities, then they need to unpack visual representations in student-centered ways. However, a key issue from a student perspective is that the teacher should also reflect on how to verbally guide the students through this process of unpacking.