Many experienced teachers make rolling out a science class appear to be easy. In reality, there is usually deep and complex thinking behind their practice. This knowledge is sometimes so intrinsic and part of their everyday practice, that it remains hidden and unexplored. This article presents data from a study that attempted to draw out such knowledge from expert science teachers by using a framework called Content Representations (CoRes). It was found that CoRes was a very useful tool for teachers in revealing aspects of, and informing their current practice, and might offer teachers a new way of viewing their professional knowledge of practice. (Contains 1 figure.)