At the microscopic level, why does pressure in a liquid increase with depth? It must be that particles deeper in the fluid are moving faster than more shallow particles, but what causes them to move faster? And why isn& #39;t there a corresponding temperature increase? #iteachphysics

This is also messing with me because my brain in so ingrained in Bernoulli& #39;s principle at this point. For a static fluid, higher pressure regions *are* due to faster individual fluid particles. The are just moving randomly and average over all directions to a speed of zero.

Bernoulli& #39;s principle, faster fluid implying lower pressure, only applies to the velocity of the *net* fluid flow. It doesn& #39;t say anything about the speed of any one particle.

Higher pressure will always be caused by more particle velocity being normal to the surface.