PocketLab sensors can measure the pressure in a fluid line easily, by putting the PocketLab into a plastic wash bottle. (For protection, put the sensor in a ziplock bag with a paper towel.) The wash bottle nozzle inserts easily into 1/4" ID tubing, and can be used as a pressure tap to measure fluid pressure in two different T junctions.
The data, unfortunately, does not match the Bernoulli predictions, due to excessive head loss between the two sensors. When flow is from larger to smaller tubing, the pressure decreases (more than expected). When flow is from smaller to larger, the pressure also decreases. Nonetheless I found this useful for hands-on measurement of fluid pressure in a piping system.