Hey Ray: The Rising Chain Experiment
PITTSBURGH (KDKA) - As we have shown you repeatedly, some things may act differently than you expect when it comes to physics.
If I were to put rope or string into a cup with a weight on the end of the string and drop it, you know the weight would hit the floor, and the rope or string would get pulled out of the cup until that weight hit the floor. At that point, everything would stop.
We are going to upgrade our string, though, with a stainless steel ball chain. We are going to perform the same experiment but without the weight on the end of it.
When I drop the chain, it pulls out until the chain hits the floor, then the leftover chain in the cup keeps coming out, even though one end hit the floor.
More interestingly, though, the chain rises well above the cup.
Your first thought may be that the cup is causing the chain to run up. This is an idea that we can easily test by putting the chain in a pile, rather than a cup.
You can see that this ball chain behaves the same. It lifts as the chain spills over the edge to the floor. That means the cup is not helping to lift our chain.
So, what is happening?
It is no secret that the initial pull you give the chain sets it into motion, and gravity continues to pull the chain from the counter to the floor. That would explain it if the chain just slid downward. The secret to the rising fountain is in the links of the chain. The chain is set into motion by gravity, and a series of a few little metal balls make those few segments of the chain more rigid.
As that chain is pulled, the top of the link rotates upward, which means the next couple of beads or balls below it are pushed downward. The bottom of the link pushes downward on the rest of the chain pile and table. Since the link can't push through the table, that push results in an upward force causing the chain to lift and continue to fall.
The harder the pull, the higher the chain will lift. That means the higher the starting point of the chain is above the floor, the higher the chain will lift from up before spilling over.
This experiment also works well with a long string of plastic beads, too.