A considerable body of research examines people's perceptions of the nature of science. There is also extensive research about what those perceptions are for teachers, and what strategies can be used to change them. There is, however, very little information about what these perceptions may be in the case of computer science. In fact, computer scientists struggle to agree on a definition of their discipline, and perhaps the only term common term to all existing definitions is that of computational thinking. This paper reports on an investigation into perceptions about computer science occurred during a series of professional development workshops for Australian Digital Technologies teachers. These workshops aimed to promote the computer science discipline by providing skills and resources necessary to teach computer science and computational thinking. The results of our investigation indicate that Digital Technologies teachers in our sample (N=16) had one common misconception about the nature of computer science. We also found that the misconception was changed after 3 days of intensive education about computational thinking, computer science and its applications.