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===== Galilean Spacetime Diagrans: Instructor's Guide =====

==== Main Ideas ====

Representing motion as worldlines in a spacetime diagram.

==== Students' Task ====
//Estimated Time: 20 minutes, including wrap-up//

Students should be asked to answer the following questions on their
whiteboards:\\\\
//
Draw a diagram representing yourself, standing still.\\\\
Draw a diagram representing your partner, moving right at 5 mph.\\\\
Draw diagrams representing each of you throwing a ball to the right at 10 mph.
//

==== Prerequisite Knowledge ====

None.

==== Props/Equipment ====

  * [[:Props:start#whiteboards|Small whiteboards]] with markers

==== Wrap-Up ====

  * Ask several students to present/defend their responses.
  * Ask how fast each observer sees each thrown ball move.
  * Ask students to explain how to answer this question from the diagram.
  * Conclude that speed is (reciprocal) slope.