• Length contraction is just the result of different observers making different measurements.
• Spacetime diagrams can be calibrated using hyperbolas.

Estimated Time: 30 minutes, including wrap-up

Students should be asked to answer the following questions on their whiteboards:
Draw a diagram showing a meter stick on a moving train.
Draw a diagram showing a meter stick at rest.
Calibrate these diagrams using unit hyperbola.

Basics of hyperbola geometry.

• Small whiteboards with markers

• Ask several students to present/defend their responses.
• Construct right triangles with unit hypotenuse in both reference frames, emphsasizing the location of the right angle.