Hi everyone. I have a problem with my device. It consists of a parallel plate capacitor with plates made of galvanized iron. Each plate's area is 1mx1inch. It's connected to a bleeder resistor and basically, the circuit is just a simple RC circuit. The source I'm using is a constant 5V DC source. The plates are not protected which means it is open. Here is an image of the capacitor: https://pbs.twimg.com/media/CGtYSZgUIAAOaFF.jpg [Broken] the water acts as the dielectric material. I'm trying to find the relationship of the voltage across this capacitor and the water level. so far, I found out that the relationship is logarithmic. I measured voltages for each increment of an inch from 1 to 25 inches. However, each set of measured voltages is different from each other. Which means measured voltage for a certain water level is different each time i measure the voltage. I don't know what's affecting this. The capacitor is fixed in the water container so I eliminated the effect of the water container. I don't know why the voltage on a certain water level is different each time. Can someone help me figure this out. Thanks in advance.