Bernoulli's Equation vs Newton's Laws in a Venturi

Often people (incorrectly) think that the decreasing diameter of a pipe correlates to a smaller volume and thus higher pressure. But the ideal gas law has no place in INCOMPRESSIBLE fluid flow.

Others try to explain the decrease in static pressure using Bernoulli's Principle, however, unless you have a VERY good handle on Bernoulli's, that is mostly a self supporting argument.

Back all the way up to Newton's 2nd Law to understand why there is a decrease in pressure in a pipe taper.