For the "build your own sensor" part of my AS work I am using a thermistor in a potential divider in order to measure the melting point of a chemical. My teacher has OKed this but says that i need to calibrate the sensor in, for example, melting ice. Im not sure exactly what this involves, other than changing the value of the other resistor in the potential divider. Am I just trying to get a sensible value for the voltage output? What value should i be trying to acheive? Is the curve produced by a thermistor not non-linear? In this case how do I, after calibration; and after i have a voltage output value for when my chemical has melted/solidified; find the temperature value from the output, without using the data sheet for the thermistor? Any help you could offer would be appreciated.