This study is on using information and communication technology (ICT) in science education in Iceland. The requirement that ICT be utilized in teaching has only been met to a limited extent though schools appear to be well equipped. Data was collected through a mixed methods approach including a survey, interviews, and an intervention with eight science teachers. The study showed that teachers use equipment available to them but access to computers for pupils’ use is limited. The uses are primarily researching selected topics on the internet for writing essays or other products, watching video-clips and taking photos. Use of science specific applications is rare. Support structures for science teachers are weak and CPD opportunities scarce. Teachers have positive views towards ICT in teaching science. However there are considerable barriers to technology integration, teacher knowledge is a central element and resources, support and time are major factors affecting teachers’ use of technology. Four cases are explored through cultural historical activity theory, analysing the contradictions that are at work in the context of teaching science with ICT. This analysis illustrates how resources, knowledge and more latent factors are pivotal in the extent and proficiency of teachers’ technology use. Three interventions with a quasi-experimental design explore the effectiveness of a selection of digital learning resources (DLR). The results show that benefits from using DLR’s vary. In two topics the experimental classes scored significantly higher than the comparison classes but in the third it was the opposite. The findings indicate that DLR’s will have a more positive effect on learning results the more interactive features they contain. A further finding from the research concerns the expertise and impact of the science teachers’ pedagogical content knowledge (PCK). Perhaps not surprisingly, pupils of teachers with strong PCK tended to score higher, indicating that successful ICT based learning is related to teacher PCK.