Michael Young has written extensively about "powerful knowledge" as the type of knowledge that should be central in education: knowledge that is -- among many other things -- reliable and potentially testable, that helps us understand the natural and social world, and offers us a language to engage meaningfully in moral and political debates. As a contribution to the powerful knowledge debate, the authors introduce a so-called knowledge curve, depicting types of knowledge along the axes of level of abstraction and degree of explanatory power. They argue that combining elements of knowledge that are situated on different positions on this curve is what makes the use of knowledge and the thinking process powerful. The implications for school geography are illustrated with the example of global south to north migration.