When water flows continuously in a pipe, the amount of water flowing past any given section of the pipe is the same as the amount that flows past any other section of the same pipe. This is true whether the pipe widens or narrows. As a consequence of continuous flow, the water will slow down in the wide parts and speed up in the narrow parts. Daniel Bernoulli found that the pressure at the walls of the pipes decreases when the speed of the water increases. Bernoulli's Equation tells us how much the pressure within a moving fluid increases or decreases as the speed of the fluid changes. Here is Bernoulli's equation: Pa+1/2pv2a+pgha=Pb+1/2pv2b+phgb where is the first point along the pipe is the second point along the pipe is static pressure in newtons per meter squared is density in kilograms per meter cubed is velocity in meters per second is gravitational acceleration in meters per second squared is height in meters