Number of coils held
Observations
Slinky drop length
The ball never appears to leave the top of the slinky. Even as the slinky bounces off the pad at the bottom of the clip, the ball remains on top of the slinky, throughout the entire bounce. Perhaps the top end of the metal slinky became stuck to the baseball before release. After this drop, the ball came apart from the slinky rather easily with a pull.
45 coils
A longitudinal wave can be seen forming gradually in the slinky, becoming prominent about one-third of the way through the clip. The ball appears to have moved relative to the top end of the slinky, between the time of release and when the wave collides with the bottom of the slinky. Like the
previous case, the ball remains in contact with the slinky throughout the drop.
Compare with
slinky dropped independently, 50 coils held,Or
view a clip.
30 coils, drop 1
This is the first set of clips in which the top end of the slinky falls faster than the baseball. In this drop, the wave moves down the slinky with a slight horizontal component of motion, which appears to cause the slinky to rotate in the horizontal plane once it fully collapses. The second drop shows a more uniform fall. The top end of the slinky clearly experiences a greater downward acceleration than the baseball does.
Compare with
slinky dropped independently, 30 coils held,Or
view a clip.
30 coils, drop 2
Again, the top of the slinky experiences a greater downward acceleration than the baseball. The top of the slinky overtakes the longitudinal wave that forms after release, just before it collides with the bottom. As a result, the bottom remains motionless until the entire slinky is contracted. An interesting observation is the relaxing of the slinky after collapse. The slinky relaxes slightly and appears to continue falling at the same length without change.
Compare with
slinky dropped independently, 30 coils held,Or
view a clip.
10 coils
The ball and slinky separate quickly. A longitudinal wave forms in the slinky, but the top quickly overtakes the wave before it reaches the bottom. As a result, the bottom remains motionless until the entire slinky collapses.
Compare with
slinky dropped independently, 10 coils held,Or
view a clip.
5 coils, drop 1
bottom end coil of slinky is just above the pad near the bottom of the clip
If any wave forms, it cannot be seen in either of these two drops. The top separates very quickly from the ball, illustrating how much greater its acceleration must be.
5 coils, drop 2
bottom end coil of slinky is just above the pad near the bottom of the clip
In this clip, the top part of the slinky curves over somewhat in its fall, producing an interesting bounce when it lands. The slinky's overall motion is not much different from that of the first drop.
