Why are sewer things circular and not rectangular or square?

Question

first one to get it gets 10 points
yes, there's a reason

Answer 1

To prevent the cover from falling back in.

the others can fall back in on the bias.

Answer 2

The question of why manhole covers are typically round, at least in the U.S., was made notorious by Microsoft, and Tony Martinez when they began asking it as a job-interview question. Originally meant as a psychological assessment of how one approaches a question with more than one "right" answer, the problem exerts a strange fascination on people, who seek to find alternate explanations, from the pragmatic and satirical to the philosophical. One practical answer being, "Manhole covers are round because manholes are round."

Reasons for the shape include:

* A round manhole cover cannot fall through its circular opening, whereas a square manhole cover may fall in if it were inserted diagonally in the aperture (A Reuleaux triangle or other curve of constant width would also serve this purpose, but round covers are much easier to manufacture.)
* Round tubes are the strongest and most material-efficient shape against the compression of the earth around them, and so it is natural that the cover of a round tube assume a circular shape.
* The bearing surfaces of manhole frames and covers are machined to assure flatness and prevent them from becoming dislodged by traffic.
* Round castings are much easier to machine using horizontal boring mills.
* Circular covers do not need to be rotated to align them when covering a circular manhole.
* Human beings have a roughly circular cross-section.
* A round manhole cover can be more easily moved by being rolled.
* If an automobile rolls over a dislodged manhole of another shape, the sharp corners could puncture the automobile's tire, whereas a circle doesn't have corners.
* Tradition
* Aesthetics

Answer 3

A circle optimizes the cost of surrounding material per area of opening to down a sewer or pipe line.

example

the surface of a pipe that requires a flow of 1 m^2 requires 3.54 meters (perimeter)
a square pipe with opening of 1 m^2 would have 4 meters of material . Also, rectangle pipes have stress concentration points in the corners where a round pipe would not have one.

Answer 4

before everything, planets are 3 dimensional products and must be a three dimensional shape. no longer a 2 dimensional merchandise Of all those shapes you reported, around, sq., oblong and triangular are all on the instant disqualified for precisely this reason. All that keeps to be as an selection, is globular shape. as a result, that's the reason planets are spheres.

Answer 5

A true circle is the only shape that cannot fall into its opening at any amgle.

Answer 6

They are circlular so raw sewage doesnt get stuck in the corners and become a breeding ground for bacteria.

Answer 7

I think it's just as important that we tell you "sewer things" are called "MANHOLE COVERS".

Answer 8

It is the only shape that can't fall into itself. Easy!