There's a good chance you could improve your teaching if you were to:
- speaking about duration and distance in order to calculate speed
- using full quantity algebra when calculating speeds
- relating calculations on speed to useful examples
- always being careful about specifying differences (in position, or in clock time) in order to calculate speeds
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.
- uncritical use of the word
- achieving fluency at the expense of understanding
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 Mo01TL as Mo01TLnugget09 in the full materials.