3 ms·
Perhaps because the explanation (and indeed concept) isn’t that intuitive so the comment may be read as dismissive? If you see pressure as coming from the weig
by dan-robertson 5y ago
Perhaps because the explanation (and indeed concept) isn’t that intuitive so the comment may be read as dismissive?
If you see pressure as coming from the weight of the fluid above and now replace fluids with solids for a mental model, it obviously doesn’t work: imagine two parallel rigid plates connected by some rigid structure. The top plate will represent the (fluid) boundary between the top of the barrel and the tube and the bottom plate the bottom of the barrel. If you put a narrow column of metal on the top of the top plate, then the pressure exerted by the bottom plate is, say, p. If you make that column much wider, increasing the weight above, the pressure is say 10p.
I think the problem is that this intuitive model of pressure is just wrong but if it doesn’t come from the weight of the water above, it is hard to intuitively see where it does come from.
- garmaine 5y agoYour example is completely different though. Considering neighboring water columns isn't like adding more to the top of the plate, it's like setting up an entirely different plate next door. Which of course doesn't affect the first instance at all.
- dan-robertson 5y agoThe point is that the way people typically think of the problem leads to examples like mine, and this is why the concept is unintuitive. It doesn’t matter whether the model is correct—the whole point is that it is the incorrect model many people will have or start with.