Figure 1
A typical example of the H-R diagram used in astronomy. Eriksson (2007).
Figure 2
A resource with high disciplinary affordance, but low pedagogical affordance can be unpacked to make it more accessible. Note how this process usually entails lowering the disciplinary affordance of the resource.
Figure 3
Diagram showing the surface temperature of stars of different spectral classes (colours) in the Harvard classification system. Note that temperature increases to the left towards the origin.
Figure 4
An example of an H-R diagram with higher pedagogical affordance that unpacks some of the disciplinary affordances for newcomers to the discipline. Here, the axes are labelled and directions of increasing brightness and surface temperature are depicted using arrows. The four main stages of stellar evolution are also named and ordered using the numbers 1–4.