The nature of science (NOS) is a phrase used to represent the rules of the game of science. Arguably, NOS is the most important content issue in science instruction because it helps students understand the way in which knowledge is generated and validated within the scientific enterprise. This article offers a proposal for the elements of NOS that should inform classroom science teaching and learning, including the distinction between law and theory, the shared methods of science, the role of creativity and subjectivity, the idea that scientific knowledge is tentative, long-lasting and self-correcting and the important reality that science has limits.