The Falling Slinky

W. G. Unruh
CIAR Cosmology and Gravity Program
Dept. of Physics
University of B. C.
Vancouver, Canada V6T 1Z1
email: unruh@physics.ubc.ca
The slinky, released from rest hanging under its own weight, falls in a peculiar manner. The
bottom stays at rest until a wave hits it from above. Two cases– one unphysical one where the
slinky is able to pass through itself, and the other where the coils of the slinky collide creating a
shock wave travelling down the slinky are analysed. In the former case, the bottom begins to move
much later than in the latter.