Bernoulli's Puzzle

As fluid flows through this oddly shaped section of pipe, Bernoulli's Principle predicts that the pressure will fluctuate as the pipe's diameter changes. Drag and drop the gauges to indicate the relative pressure of each section.

(Note that two sections have the same diameter. This is an ideal system with no energy conversion caused by turbulence)

The Vacuum Gauge

Why was there a vacuum pressure?

Yes, you can actually create a partial vacuum (negative) pressure with a narrow enough restriction. When fluid accelerates, the pressure drops. And if you accelerate it enough, you will go into partial vacuum pressure.