Students in England and Wales wishing to read for a physics-based degree will, in all but the more exceptional situations, be required to follow the two-year GCE Advanced-level physics course. This course includes, in its mandatory core, material that addresses the topic of ‘quantum phenomena’. Over the years journals such as this have published teaching strategies, for example Lawrence (1996), but few studies addressing what students understand of quantum phenomena can be found. This paper aims to address just this problem.