Like the shape of a bird's egg. The conical end can take more impact than the sides.
Like that.
>>Like the shape of a bird’s egg. The conical end can take more impact than the sides.
Yes, except that the egg shape allows greater impact ON the sides as well. A rectangular ceramic container will easily deform and break with an impact at the center of one of its rectangular sides. The stress vector is perpendicular to the plane of the rectangular side, the side deforms, pushes in and breaks. None of the stress is transferred laterally. With a cylinder you have laterally transferred stress in the plane of the curvature but not the the plane of the edge- better but you still get easy breakage with a side impact. With the compound curvature of the egg shape, the force of side impact is directed laterally into the clay walls in all planes, much harder to break.
The problem with earthenware is that is is slightly porous. In this case the thick walls of the amphora would prevent weeping or evaporation, but its porosity would also absorb some of the contents and thus contaminate the flavor of whatever other contents made its way inside, so you could get wine flavored olive oil and so on. There must have been some attention paid to always using the amphoras to carry a single liquid or other commodity.