Wednesday, April 21, 2010

Roped In

Physics really is the study of everything. By which I mean there is no item or process in this whole wide world that some physicist, somewhere, doesn't want to get their hands on and study. Does that make us all physicists? Even if we are biologists or chemists or cosmetologists? Does that make me a physicist if I feel like studying puppies and Cheetos? Maybe it does. All I know is, today some people who call themselves physicists went out and studied the physics (actually, the geometry) of rope.

Scientists in Denmark posted a paper on the arxiv claiming to have boiled down the nature of rope and found a law that governs when and why a rope will or will not unwind when pulled. Rope is made of strands of material, like wire or fabric, that are each individually twisted in one direction, and then twisted or braided together in the opposite direction. The beauty of rope is that materials which are actually quite weak on their own, can be manipulated to be quite strong. As the researchers stated in an article by Science News, it is a testament to the power of geometry.

So does that technically make them geometrists? Is "physicist" just a word we give to anyone who studies stuff that other departments don't know how to categorize? I don't know but I do know that these puppies really want these Cheetos. Physics?

Back on track (rope track): The researchers found that in order to guarantee that the rope does not unwind, one must twist the individual strands of material to their maximum. This they call the "zero-twist point." They then measured ropes twisted to this point and found that in a triple stranded rope, the rope is 68% the length of the untwisted material.

I love the Science News article about this in which an outside expert explains that this is a universal law for rope:

Physicist Henrik Flyvbjerg of the Technical University of Denmark, who was not on the research team but is familiar with the work, agrees: The rule of the zero-twist point is universal.

“If there is life on other planets in other solar systems, their rope makers must follow the same rules,” Flyvbjerg says.

Rope from other planets? Oooooooo.

The researchers also showed why you need to feed the individual twisted strands into the rope at a higher angle than the resting rope. To illustrate, watch the braiding machine featured in this video about how climbing ropes are made.

I could probably babble on about the history of rope, which is one of those commonly overlooked and yet totally essential tools in human development. It's one of those objects that seems to have a debated past. Ropes (distinct from chords or strings) may have been used as early as 28000 years ago, and the first rope-making tools were believed to belong to the Egyptians around 4000 BC.

Ropes made from synthetic material appeared in the 1950's, and most rope that you'd buy at the hardware store is synthetic, made from material like nylon, polyester, Kevlar, polypropylene and polyethylene. You can also find rope made from organic material like hemp, linen and cotton.

Claims for the strongest rope in the world come from a few companies. There's Zylon, which claims to be the worlds strongest fiber. Two companies that claim to have the strongest ropes in the world both have fancy sounding physics names. There's the Purple Plasma Rope from Rope Inc. and the Neutron 8 Rope! I cannot find a deciding contest between ropes for the strongest contender. If you know of one, please share.

Rope! So interesting! I'm Roped In! Hahahaha! Get it?! (Agent Utah is fired).

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