Scientists represent their ideas in a variety of ways, including models, graphs, charts, diagrams, written texts – and the measurement scales they use. Students need to understand that scientific scales have been deliberately constructed for specific purposes, and can be refined over time as they are used for these purposes. However, this does not mean that “anything goes” – understanding how critique and consensus building are used to impart authority to such scales is an important aspect of building science literacy. Understanding and using the literacy practices of science supports students to think in new ways.