Two stages in research on scientific literary are identified: a composite saturation stage in which definitions covered all objects of science education and a stage where researchers focused on small manageable portions of scientific literary. Initial and continuous scientific literacy research in which the focus is on cognitive preference for science and informal science teaching is described. Underlying cognitive preference is a value preference for science. Three interdependent but clearly distinguishable forms of science teaching, formal, nonformal and informal, are described. Informal science teaching is identified as a condition for and an outcome of scientific literacy.