Fascinating. Thanks for posting that.
My take? A released spring contracts towards the center from both ends. The movement of the spring from the bottom up is being counteracted by the force of gravity down, and so stays stationary. Just a guess.
Slo-Mo is right, I waited 5 minutes for the video to start......and it never did.
If you were to stretch the slinky longer than plain gravitational forces the bottom would actually rise before falling because the tension is more than gravity. If you compress the slinky all the way and drop it the whole thing will fall at once.
Pretty cool. Definitely gets you to think about the various forces, stored energy, etc. in play, and how they interact with one another as the center of mass of the object falls.
Looks like the folks at Looney Toons understood gravity, with some help from Wylie Coyote.
Like I read on this website one time...”Liberals are like slinkies, they don’t do much, but it’s fun to watch them get pushed a flight of stairs.”
Neat stuff!
The slinky starts out under tension, like an extended spring. The top is being pulled down toward the center and the bottom is being pulled up toward the center.
To give the slinky its other interesting properties, the spring-rate has been matched to gravitational forces.
As a result, the bottom is pulled up by the tension in the 'spring' with about the same force as the gravitational effect, so it barely moves, and that is true elsewhere in the slinky, until the coil above it has collapsed.
At the start, the second coil is pulled up by the pull from the top coil, but the top coil is pulled down by both the tension and gravitation, and falls. As it falls, the next coil down loses the pull from the top coil and starts to fall under gravity no longer balanced by the upward pull from the top coil, and so on down the slinky.
If the spring constant of the slinky were higher (or the weight of the coils lower), the bottom coil would start to rise instead of staying put -- but it wouldn't be a slinky, able to do those weird tricks, then.
Gravity works with the compression of the spring. I wonder if this changes the equations of gravity?
On a side note - the other video at the bottom of the page is hilarious! “Don’t sleep on Barry O!”
Looks cool. Conceptually it’s not tough, the slinky spring tension moves toward compressed, so when stretched then dumped into free fall the bottom is being pulled by gravity AND the top thus it doesn’t move.
Very cool!
Looks like the bottom of the Slinky was waiting for the rest of the mass to catch up with it as it fell.
Of course, Slinky WAS invented by an engineer. :)