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> Manholes covers are round because that is the shape that won’t fall in It's worth mentioning that this oft-repeated canard doesn't have much evidence. Manho
by SeanLuke 10y ago
> Manholes covers are round because that is the shape that won’t fall in
It's worth mentioning that this oft-repeated canard doesn't have much evidence. Manhole covers come in a great many shapes, and this has always been true: the Romans made them square. There are plenty of shapes which won't fall in, such as any curve of constant width. Basically fake-Feynman is right: manhole covers are round because it is often convenient to make manholes round.
- Neliquat 10y agoModern manhole covers are overwhelmingly round, and cast as not to fall into their own fitting, also cast. Not sure how a obscure counter example does anything other than disprove your point further. Source: worked IT for public civil engineer for a few years.
- SeanLuke 10y agoThere are many cities where manhole covers are overwhelmingly rectangular. I'm typing from one right now: Rome. SPQR! I used to live in a town in the US where many of the manhole covers were shaped like a D.
- zero_iq 10y agoI assume that by 'obscure' you mean 'outside your-state, USA'. Here in the UK, rectangular manhole covers are the overwhelming majority.
- joncrocks 10y agoI think the point is that a circle is not the only shape that can't fall into it's own hole/fitting, so it's the combination of this fact along with other factors that make a circular cover popular. https://en.wikipedia.org/wiki/Manhole_cover#Circular https://en.wikipedia.org/wiki/Manhole_cover#Circular