How would this have been stored so it didn't tip over?
These vessels were placed either in holes in the mud floor of a house or in pot stands of clay or wood. Occasionally representations of these vessels show them simply leaning against a convenient wall.
How come the bottom is round instead of flat?
These vessels would be placed in a ring or in the sand so the rounded bottom would actually make it easier for them to stand upright.
Can these jars stand on surfaces or are they designed to be held somewhere?
These jars were indeed intended to sit on stands that also would have been made of terracotta. They could also be leaned against walls or nestled into the sand.
Pot stands were an important feature of life in ancient Egypt! There is even a hieroglyph that looks like one.
Why was the grain storage jar in the Egyptian exhibit designed in a way that prevents it from standing up straight without support? Were the jars stored on their sides, or maybe upside down? If it was the former, wouldn't they roll? I'd assume you'd display them differently if it was the latter.
They were either placed on stands much like Roman amphora or leaned against a wall or each other. They could also be placed in holes in the mud floor of a house. In terms of storage in the ground it could have been convenient to have a pointed end to help not only create a hole but also stabilized the pot.
That seems a little unstable, right? These stands better be amazing.
I also just found reference that in the case of unglazed pottery which was somewhat porous, if it was being used to store liquid, the stands would catch surplus water that oozed out and prevented dirt from sticking to the moist outer surface of the pot. Plus, the ancient world actually had far fewer hard, level surfaces than our modern one making vessels that had to be nestled actually a more stable option.