Chapter 9 was about the helix. A segment will always fit, no matter if the curve can be slid along the curve from one end to the other or if a straight segment fits snugly into a straight scabbard. The main question of this chapter was "Is it possible to design a sword and its scabbard that are not either straight or curved in a circular arc?" Most people answer no but are wrong according to Martin Gardner (the author).
A circular helix is a curve that coils around a circular cylinder in such a way that it crosses the "elements" of the cylinder at a constant angle. If you restrict the curve until the coils are close together you get a cramped wound helix resembling a Slinky toy then when you let go the helix topples into a circle. If you stretch the helix it is transformed into a straight line. Most manmade helical structures come in both right and left forms such as: candy canes, circular staircases, rope and cable made of twisted strands. Helical structures are also in living forms like parts of the human body. The genetic code carries information that tells each helix strictly "where to go". Linus Pauling's work is base upon the helical structure of protein molecules. Researchers found that there has been increasing evidence that every giant protein molecule found in nature has a "blackbone" that coils in a right-handed helix. A "blackbone" is a chain made up of units each one of which is an asymmetric structure of the same handedness. In the human ear, the cochlea is a conical helix that is left-handed in the left ear and right-handed in the right ear. On any occasion, a single helix is outstanding in the structure of any living animal or plant, the species usually environs itself to a helix of a specific handedness. The Devil's corkscrew is a puzzling typer of helical fossil, which is found in Wyoming and Nebraska. Helices in the plant world are common in the structure of stalks, stems, seeds, flowers, tendrils, cones, and leaves. The enmeshing of two circular helices of differing handedness is also elaborated in a remarkable optical-illusion toy that was sold in this country in the 1930s. The helix aspect of the neutrino's path outcomes from the fusion of its forward motion with it's "spin". Examples of this are: a point on a propellor of a moving ship or plane and a squirrel running up or down a tree.
This chapter to me was a very easy to read and easy to understand. I didn't know much about the helix before this reading and I can honestly say that I have captured a lot more after reading about the helix. I wouldn't say the chapter was surprising by any means, there wasn't anything that I read that was surprising to me.
I thought this chapter was pretty cool. I didn't know that there were so many types of helices found in our surroundings! I agree in that the chapter was pretty straight forward, but at some parts, I needed to re-read some lines to get the gist of what it was saying.
ReplyDeleteI liked your explanation of the helix. It was cool to read about and very interesting. I found it cool that if you stretch the helix it would become a straight line and it also surprised me that there are helical structures in parts of the human body.
ReplyDeleteYour summary of the chapter was well put together. I liked this chapter mainly because of the topic of the helix, which interests me. One particularly interesting thing that you mentioned was that if you were to pack a helix it would look like a slinky, and if you released it, it would topple into a circle.
ReplyDeleteThis is a very interesting topic as the helix is seen in many areas; from galaxies down to plants and animals. I would like to know how true this claim is: That squirrels chasing one another on tree trunks follow helical paths? Good job on the summary, deepened my understanding
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