The question occurred to me while re-reading Little House in the Big Woods.
Grandpa Ingalls is described as making buckets for collecting maple sap. The illustrations show the buckets as round, as most buckets are of course.
However, it seems to me that making round buckets from scratch using wooden staves would be a pain in the ass. Is there a reason square buckets wouldn’t work? Would they leak or something?
Of course now, with plastics, you can make buckets whatever shape you want. But when the average person thinks buckets, they think cylindrical.
Is this just habit? Or do square buckets not work well?
Depends what you’re putting in the bucket. The cat litter I use comes in square buckets. Makes it easier to store a bunch of them close together with no wasted space, I think. The lids are made so the buckets can stack, too.
This is the correct answer. Wooden barrels and buckets are created by straining the staves against metal rings - if the rings were square, rather than circular, the forces acting on them would be trying to bend them toward a more circular shape.
Buckets are actually round for similar reasons that soap bubbles are round - it’s all about forces pushing outwards against a constraining boundary.
Round iron hoops to bind staves, etc. - remember the round hoops could be heated, hammered onto the tapered barrel ends, and pushed down to where they forced the staves into a tight seal. The more acute the angle, the more likely you get a slip (broken corner) than a seal, so an n-go is more stable and solid than a square. For simpler construction, like the parts of a water wheel, you do see rectangular “buckets”. If that leaks a bit during the 1 or 2 seconds it’s holding water - who cares?
Aside from the issue of force, round is an efficient use of materials, too. A round bucket that holds a given volume is going to require less stuff to make the bucket than a square bucket that holds the same volume.
Optimal (in terms of materials) would be a hemispherical bucket, but that would be awkward for a number of reasons.
I guess the unstated fact in this design is that the wooden slats are under constant compression by the hoops. Otherwise the bucket would leak water at the seams between the slats. A square bucket could be made more easily, but it would be harder to apply the constant force required to keep the seams closed.
Remember also that the earliest examples of buckets would have been made of hide, intestine or some other animal material that would need to be sewed to make water-tight. One seam is best. Of course, if they use a stomach or length of intestine with a knot in it, no sewing is necessary. All of this would be done well before the smelting of metals for hoops and nails.
Surely they’d be more likely to be woven from grasses or strips of bark? They wouldn’t be water-tight in the long term, but for short-term use, they’d be just fine.
Might also have to do with how wide thin wooden sides of a bucket would be more likely to crack and split with the wet dry cycles. The thinner staves can swell and shrink with less chance of that.
They stayed round though, after plastic came along. I suspect this is because liquid sloshes less in a round bucket. Any straight side will make the liquid stop fast, and rush against itself, increasing the chance of it going over the edge. In a round one, the water tends to swirl, and so stay inside.