Subject: calculate the effect of temperature on a resistor

we need to find out how to predict the resistance change when the temperature
changes.We thought than we are going to heat a wire up and cool one down with
ice and measure the change in Voltage and calculate than the resistance with
ohm's law.
Our project includes than we schould be able to predict this change. We thougt
than we can calculate the thermal energy of 
the wire add that to the electric energy from the series in normal condition and
than solve the equation P=IxIxR for R. Our problem is to calculate the thermal
energy of the wire.
Thanks 

Re: calculate the effect of temperature on a resistor