I'd like to explore water pressure by having students build water towers out of both 2-liter bottles and thinner 1 liter bottles. 1. Assuming they build towers of the same height and fill them with the same type of water, we should see the same water pressure for identical heights within the towers correct? 2. Looking for some ideas on how to read the pressure. Are there gauges available to read the pressure at the bottom of each tower? I read somewhere that 1 psi can be generated with each 2.3 or so feet of water depth. I had initially thought to attach the valve stem of an old inner tube to the bottom of each tower so that pressure could be read using easily available tire pressure gauges, but they don't appear to be sensitive enough.