What Happens When You Drop a Slinky
High speed cameras finally put the myth to rest. 
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29 
Science-FAIL!!! 
Why bother trying to explain the phenomenon to people if you're dumb enough to use expressions like "It KNOWS"... WTF! It's a thing! There were thousands of better ways to explain this... 
cool 36
What crap show is this - where they don't even know how to explain plain simple things. Why mangle physics?
25
Like #1 and #2 said, this is a misleading and childish explanation.
While the spring above the bottom is stretched, it is properly "hanging" on the higher parts of the slinky, its environment is exactly the same as before the top is released. The same holds if there is a tennis ball there. At the moment of release, the forces are unbalanced only for the topmost part. The disturbance then propagates downwards like waves.
If you observe the center of mass, it falls just like any other object. Only the shape of the object changes in a way that some parts remain stationary for a while. Kinda like a falling cat, only the cat's motion is much more complicated.
42
9. loadrunner 235 days ago
What walks down stairs, alone or in pairs
and makes a slinkity sound?
A spring, a spring, a marvelous thing!
Everyone knows it's Slinky...
20
Well just physics at work. But all science on the side - the cool part was how the bottom looked almost still in time. Hax 
22
13. Comment rated too low. Show this comment detonatordan 235 days ago
What a large amount of mis-wording, Hey I was once rewarded a pardon from a judge for a cop mis-wording my charges by saying I knowingly did a misdeed!The bottom of the slinky knows nothing! It knows absolutely nothing! Idiocy in human communication! It just doesn't reacts to the force of gravity that's pulling the top half down until it reaches it! And no one could prove what I knowingly or not knowingly did by automatically saying that I knowingly did it, because, as the judge said: "No one knows what I know"!ingly am doing or not!' Anyways this video is stupid!
9
#2 I would really like to see posted one of the thousand better explanations that you have....oh sorry...i forgot that criticism gets more "points" or "hits" or whatever.
28
So if you terminate comunications between the uppet and the lower part, the thing will levitate ? 
34
I have played with the Slinky before but never really understood it. This scientific explanation amazed me.
25
Funny, everybody is bitching about the bad explanation, but the correct one gets negative rating. No wonder this kind of pseudophysics is so common. People obviously like it better.
22
#7 kind of said this already, but to hopefully make it clear for everyone, here goes:
Both ends have a tension caused force vector towards the center point of the coil equal to the gravitational force. We can know this because the lower part is stationary and the Slinky is symmetrical. When the top is released the bottom still has the same forces in effect as it had before. The top however now lacks one force - the hand - and thus starts moving. Because the coil is so soft, the new downward force vector doesn't transfer to the bottom until they pretty much collide.
A more rigid coil would most likely start moving at the bottom too, as the kinetic energy of the falling top would partially transfer to the bottom part. A completely rigid object would (obviously) have both its ends moving instantly.
Basic kinetics in action. 
7
What is this "downward force vector doesn't transfer " rubbish? You are as bad as the guy in the clip. The slinky is in free fall. Because the stretching force on it before it started was gravity, when it was released the ends accelerated towards the middle at roughly the acceleration of gravity (it is a spring, storing force exactly is what we use them for). The top is accelerating down at G + G, the bottom is doing G - G until the spring is used up. And G - G = 0 so no relative motion.
(110 votes)
+28
1. Limberg 235 days ago
the bottom doesn't know squat! it just does what the forces dictate... this kind of language is why people won't understand the physics of this experiment.