Abstract: We have identified ‘scale’ as a threshold concept that students must overcome to make progress in A-level chemistry. We have developed a new teaching sequence that is presented in order of increasing scale, from smallest subatomic particles to atoms, then molecules, then giant structures. The sequence includes several concept spirals, so that key chemistry ideas are met on multiple occasions at different levels of scale. This sequence is ideal for introducing ideas related to bonding and structure at the start of an A-level course. We have observed a dramatic shift in the type of questions students ask towards higher order, inquisitive questions, suggesting they are thinking much more deeply about the content than previously.