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How Gauss Taught Us the Best Way to Hold a Pizza Slice

182 pointsby _mayoover 10 years ago

11 comments

ubasuover 10 years ago
The author&#x27;s point that &quot;curvature imputes stiffness&quot; conflates several different and distinct mechanisms, and offers an inadequate explanation.<p>For the examples of the pizza, the leaf, and the corrugated sheets, the stiffness is due to the fact that the bending moment of inertia of the cross-section increases when we fold the pizza or the sheet in a particular way [1]. The Theorema Egregium shows that such a structure can be made from a flat sheet of material, not that this construction imparts stiffness to the structure.<p>The example of arches show the well-known arch action in mechanics, where forces are carried through pure compression without any tensile stresses, which makes it appropriate for using stones to make the arch [2]. In principle, one could make a triangular &quot;arch&quot;, i.e. part of a truss structure, where we use two straight rods joined together at the top [3]. This shows that its not really the curvature that is giving the stiffness.<p>The example of hyperbolic paraboloids shows arch action in one direction and beam bending in the other.<p>The examples of the egg and the can show that it is hard to break a surface when it does not have stress concentrations [4].<p>So the point is that there&#x27;s a lot of classical solid mechanics at play here, of which the author seems to be unaware.<p>[1] <a href="http://en.wikipedia.org/wiki/Bending" rel="nofollow">http:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Bending</a><p>[2] <a href="http://en.wikipedia.org/wiki/Arch" rel="nofollow">http:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Arch</a><p>[3] <a href="http://en.wikipedia.org/wiki/Truss" rel="nofollow">http:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Truss</a><p>[4] <a href="http://en.wikipedia.org/wiki/Stress_concentration" rel="nofollow">http:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Stress_concentration</a>
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suprgeekover 10 years ago
The Oatmeal provides a very nice illustrated pics about the Mantis Shrimp and its killer claws <a href="http://theoatmeal.com/comics/mantis_shrimp" rel="nofollow">http:&#x2F;&#x2F;theoatmeal.com&#x2F;comics&#x2F;mantis_shrimp</a>
StavrosKover 10 years ago
I totally call bullshit on not being able to crack an egg. Next time I see an egg, I&#x27;m trying it.
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DINKDINKover 10 years ago
More of an engineering problem that uses a bit of math. Unless you can state what the weight would be to cause the surface to collapse, you&#x27;re just wanking off in math space.<p>See Second moment of Inertia (or area depending on who you talk to) <a href="https://en.wikipedia.org/wiki/List_of_area_moments_of_inertia" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;List_of_area_moments_of_inerti...</a>
raphinouover 10 years ago
Dont the hyperboiloid chimneys have something with maximizing its surface? I think i remember sth like that from a course, but it is too far.... can someone confirm&#x2F;reject?
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grogenautover 10 years ago
why oh why do I keep falling for wired linkbait. I didn&#x27;t learn this from a mathmatician, the pizza just sluffed in my had the right way one time and it stayed.
jordighover 10 years ago
Huh, why does the original Wired article say &quot;19th century math genius&quot; instead of &quot;Gauss&quot;? Is Gauss really that unknown to Wired&#x27;s audience?
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anigbrowlover 10 years ago
Next week in Wired: How Newton taught my dog to catch rubber balls.
mach5over 10 years ago
you know how i know you all are not from the northeast?
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mhurronover 10 years ago
He used a knife and fork?<p>I found the article very interesting.
hayksaakianover 10 years ago
I&#x27;ve noticed this article is amongst a growing trend of articles that purport to solve &#x27;non problems&#x27;<p>From wired, no less.