How do I calibrate a thermistor for measuring the melting point of a chemical?

[richMMIV]

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. I am 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 achieve?
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.

 

[M98Ranger]

Calibrating a thermistor involves determining the relationship between its resistance and temperature. This is important because thermistors have a non-linear response to temperature, meaning that the resistance changes at a different rate as the temperature changes. In order to accurately measure the melting point of a chemical using a thermistor, it is crucial to calibrate the sensor first.

To calibrate the thermistor, you will need to measure the resistance at different known temperatures. One way to do this is by using melting ice, as your teacher suggested. Ice has a known melting point of 0°C, so by placing your thermistor in a container of melting ice, you can measure the resistance and corresponding temperature. You can then repeat this process at different known temperatures, such as boiling water (100°C) or room temperature (around 25°C).

By plotting the resistance values against the corresponding temperatures, you will be able to create a calibration curve for your thermistor. This curve will allow you to determine the temperature based on the resistance measured by the thermistor. When measuring the melting point of your chemical, you can use this calibration curve to find the corresponding temperature for the resistance value recorded by the thermistor.

In order to achieve a sensible value for the voltage output, you will need to adjust the other resistor in the potential divider until the voltage output falls within the range of your measuring equipment. The exact value you should aim for will depend on your specific setup and equipment.

In summary, calibrating a thermistor involves determining its resistance-temperature relationship, which is essential for accurately measuring the melting point of a chemical. By using known temperatures and plotting a calibration curve, you can then use the thermistor to measure the temperature of your chemical without relying on the thermistor's data sheet. I hope this helps and good luck with your AS work!