Thermistor relationship, linearizing (really easy)

[gRACK]

hello,
I'm doing coursework on using a thermistor as a temperature sensor. For my preliminary readings I had to choose between 3 different thermistors.

Is it true that, for example, a 22k thermistor has a resistance of 22kohms at 25 degrees? (my tutor told me this) likewise, a 15k thermistor has a resistance of 15kohms at 25 degrees? My results don't show this at all; they're completely off. (eg. 6kohm resistance at 25 degrees for a 10 kohm resistor..)

I've looked at some thermistor datasheets but i can't make head nor tail of them. could anyone give me a range of the types of resistances I should be getting, please?

Also, anyone advice on how I should linearize my results? I understand that the resistance-temperature graph is non-linear. do I: Record the voltage at different resistances (and therefore temperatures) and plot a voltage-temp graph?

but this won't be a straight line, am i right? so/do I have to plot a tangent to my curve?

i'm just really unsure of what I'm doing, I've heard/read different things. Thanks in advance for any help, it is muchly appreciated.

 

[Mindscrape]

What are your units of temperature? Thermistors vary quite a lot I suspect. Could you post the links to the data sheets?

 

[kamerling]

A 10 kohm resistor should indeed have a resitance of 10 kohm at 25 degrees celsius.
I found some datasheets here

http://www.omega.com/temperature/Z/pdf/z256-257.pdf

You are measuring the resistance with a voltage small enough to not procuce heating in the thermistor?

You could plot the logarithm of the resistance against the temperature.