Description: A flat surface is quickly removed from underneath the slinky, allowing it to drop vertically. 

Problems: Friction between the surface and slinky causes the slinky to tilt horizontally as it falls.

Description: The slinky is held at both ends, is contracted, and is then dropped. 

Problems: Fingers unavoidably release different portions of the slinky's bottom at different times, imparting horizontal tilt to the slinky's motion.

Description: The slinky is held freely by the top end coil, and is released after it has reached equilibrium. 

Problems: Slight motion caused by holding the slinky at its top end and air currents in the room keeps the slinky from perfectly reaching equilibrium. However, this problem was minimized by lowering the slinky to the floor, then carefully raising it to drop height.

Description: The slinky, at contracted length, is made to roll off a flat surface. 

Problems: The flat surface may not have been perfectly level at the moment of release. Care was taken to make sure that all portions of the slinky rolled off the flat surface at the same time by moving the slinky to the edge of the flat surface and tilting the surface slightly to allow the slinky to roll off.

Description: The slinky is now at horizontal relaxed length, and is made to roll off a flat surface. 

Problems: Again, the flat surface may not have been perfectly level at the moment of release, but care was taken to minimize this problem.

Description: The slinky is held by its two end coils only, and is kept at horizontal relaxed length before dropping. 

Problems: There was no way to make sure that both hands held the slinky at the same height, and that the slinky was not tilted in planes other than the horizontal. Upon release, slight motion from fingers likely influenced the slinky's fall. Also, both ends of the slinky could not be released exactly at the same time.