MathWorlds is a piece of educational software that allows students to explore a variety of topics related to the mathematics of change and proportionality, utilizing dynamic graphs and animated "worlds". SimCalc is the package of MathWorlds software plus curriculum and teacher professional development, and has a history of significant success in single classroom studies. According to Simonsen and Kensing (1998), "users will not change the way they work to adapt to a computer system if the benefits are not significant and obvious." While researchers know SimCalc has a significant impact on student outcomes, is this obvious to the teachers? One powerful source of information about this question is the corpus of extensive phone interviews that my colleagues and I conducted with teachers after they completed the SimCalc curriculum.

Many of our teachers recognized SimCalc as something that could be beneficial for their students. Besides raising test scores, teachers using SimCalc introduce more complex mathematical ideas to their students, which have ordinarily been considered outside a normal 7th grade math lesson. This was reflected in the phone interviews when treatment teachers mentioned more complex mathematical ideas than the control teachers. However, some treatment teachers struggled with using SimCalc because it was so different from their current teaching methods. In this case, SimCalc was not compatible with their current teaching methods. Also, for some teachers, using technology such as MathWorlds is a complex process with many hurdles to overcome. Future research must investigate ways to bridge the gaps in teaching methods and encourage more support for teachers using technology. By doing this researchers can make SimCalc more compatible for teachers with different teaching methods and reduce the number of obstacles teachers face when using technology in the classroom. With continued effort, research and support, we can look forward to the diffusion of more educational innovations such as SimCalc.