(Lecture: 10 minutes)

• Introduction to parable of surveyor's parable
• Use same units
• Distance is invariant
• Conversion is rotation

Based on the first two paragraphs of §5.1 of the text.

This is the first of two short lectures based on the surveyor's parable, introducing the parable in its Euclidean setting, where its consequences are rather obvious. The second lecture then discusses the implications for special relativity, setting the stage for the use of spacetime diagrams.

Both lectures can be given the same day, although it is quite effective to end one day with the first lecture, ask students to reflect on it, then begin the next class with an interactive version of the second lecture.