There's a good chance you could improve your teaching if you were to:
- exemplifying seeing in the lived-in world using the source–medium–detector model
- emphasising the trip time as a delay between source and detector
- working up some convincing demonstrations that light seems to travel in straight lines
- always explicitly accounting for reductions in brightness
Work through the Physics Narrative to find these lines of thinking worked out and then look in the Teaching Approaches for some examples of activities.
- speaking or acting as if light was just there
- assuming that how we see is well understood
- assuming that seeing is all accounted for by the physics
- conflating rays (the theoretical construct) with light beams (the physical)
These difficulties are distilled from: the research findings; the practice of well-connected teachers with expertise; issues intrinsic to representing the physics well.
This appears as Li01TL as Li01TLnugget12 in the full materials.