I have just performed an experimental measurement of the specific heat of various metals by introducing an electrically heated probe and measuring mass and temperature difference with respect to the energy delivered by the probe.

However, after all measurements are performed, and after comparing the results with the theoretical values, the specific heat for every metal is somewhat higher than the theorical value. I have considered that all heat comes from the probe and there is no work loss in the process.

I don’t know why they are so different given that the values have been obtained within a acceptable error.

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    $\begingroup$ Which theoretical values? If you are early in solid state physics you will find the simple theories are incomplete: $\endgroup$ – Jon Custer Feb 8 '19 at 15:50
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    $\begingroup$ What do you understand by 'the theorical value'? $\endgroup$ – Gert Feb 8 '19 at 15:51
  • $\begingroup$ @JonCuster They have been obtained from this referenced book: Tipler, Paul A., Physics for Scientists and Engineers, 4th Ed., W.H. Freeman, (1999). $\endgroup$ – margobra8 Feb 9 '19 at 17:17
  • $\begingroup$ @Gert The theorical value refers to the reference value found in the book cited before $\endgroup$ – margobra8 Feb 9 '19 at 17:17
  • $\begingroup$ These are not 'theoretical'values, they are empirical values, like yours. The discrepancy is measuring error on your part. $\endgroup$ – Gert Feb 9 '19 at 18:05

The simplest way that measurements of this type get errors in them is heat loss. If some of the heat you are putting into the sample leaks out during the experiment, it will appear as if the material has an anomalously high heat capacity, because some of the heat input is not increasing the internal energy of the material but is instead sneaking away into the night.

I am assuming here that your apparatus is insulated- but no insulation can be perfect. What you need to do is run an experiment with NO metal in the test chamber and measure the rate of heat leakage through the insulation. Knowing the rate of heat leakage allows you to subtract this term from your data and obtain a corrected value for the true heat input to the sample, and then recalculate the heat capacity for the sample.


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