Why may the specific heat capacity practical using oil and a beaker be inaccurate?

The specific heat capacity practical may be inaccurate because thermal energy is passing out of the beaker into the air, this problem can be reduced by using an insulator with a lower thermal conductivity Secondly, not all the thermal energy passes into the oil, this can be reduced by ensuring the immersion heated is fully submerged in the oil. Thirdly there could be inaccurate readings of the thermometer, which can be avoided by using an electronic temperature probe And lastly, thermal energy may not be spread evenly through the oil which can be reduced by stirring the oil