Special Relativity: Fit a 100 foot Train into an 80 foot Barn

A 100 ft train races through an 80 ft barn at 80% of light speed. The farmer says it fits; the passengers say it never does. See length contraction, time dilation and out-of-sync clocks, and how both sides can be right.

About 5 minutes. Sound on. Space pauses, arrow keys skip sections.