Number of coils held

Slinky drop length

drop 1

drop 2

Observations

Because of the lighting, the pulse can be seen clearly as it travels along the slinky. The top of the slinky leaves the ball behind soon after release. This means that the top is experiencing a greater acceleration than that due to gravity alone.

drop 1

drop 2

Observations

The two bright spots that appear shortly after release are reflections off the 10-coil clump at the top of the slinky. As the slinky further contracts, the clump grows larger as more coils become added to it. Upon release, the ball still separates from the top of the slinky.

drop 1

Observations

The distance between the top of the slinky and the pulse gradually decreases until both the top and the pulse collide to form one large clump of coils. The ball separates from the top upon release, although it does so more slowly than when only 10 coils are held.

drop 1  

Observations

This clip is a good demonstration of why the bottom of the slinky remains motionless until the pulse reaches it. Initially, the slinky is completely relaxed under its own weight. When the top is released, the bottom does not immediately "know" that the top has been released. If it did, then the bottom would begin to fall immediately. The pulse generated by the release of the top is the method used to "inform" the rest of the slinky that it has just been released.

drop 1

drop 2

Observations

Upon release, the clump of coils at the top begins to decrease in thickness, then the clump begins to rebuild itself as the top continues to fall. Near the end of Drop 1, the pulse just barely appears to collide with the bottom before the top reaches the pulse. Holding 30 coils, the bottom of the slinky moves before the entire slinky collapses, for the first time in this sequence of clips.

drop 1

drop 2

Observations

With increased clarity in this clip, the decrease and subsequent increase in the thickness of the clump at the top can be seen over time. Near the end, an interesting effect occurs. When the pulse collides with the bottom of the slinky, several coils, which together form a clump roughly the same thickness of the pulse, spring away as if the coils were balls on a Newton's Cradle.

drop 1

Observations

In this clip, the top of the slinky never seems to leave the surface of the ball until much later. This means the top is accelerating only slightly greater than the acceleration due to gravity. Unlike the previous clips, this clip shows that the distance between the top and the pulse is increasing. The pulse reaches the bottom of the slinky before the top overtakes the pulse, and as a result, the bottom of the slinky is set into motion.

drop 1

Observations

With the greatest degree of clarity within this sequence (7x zoom), we can see an almost complete transfer of coils from the clump at the top to the bottom of the slinky. The coils are transferred through the motion of the pulse.

drop 1

Observations

This last clip, taken at 1x zoom, shows that the entire slinky eventually contracts. Although the bottom has been set into motion from the collision between the pulse and itself, the top continues to fall (at the same acceleration as before?) and merges nicely with the rest of the coils.