A numerical method to determine the variations of temperature is presented. The problem of measurement of the variations of temperature is mathematically modelled with the help of the one-dimensional heat conduction equation. This equation describes the heat transfer through an insulated long cylindrical rod. The variation of the temperature which is produced near one end of the rod is determined using some measurements of temperature in the other end of the rod and the mathematical model. This rod works as an attenuator of high temperatures and as an amplifier of low temperatures.