This thesis work provides a detailed introduction to the casting process and the molding materials normally used in foundries.  The work continues with the understanding of different aggregate types, their granular and thermophysical properties. Furthermore, results from earlier authors and their methods to study the thermophysical properties of molding materials are presented. Then, the thesis work narrows down to the foundry grade silica sand, since the aim of the work was to study the various factors affecting the thermal behavior of the most commonly used basic aggregate.  The work involved studies on the effect of thermal expansion and specific heat of silica with different purity levels, grain sizes, and temperature variables. Thermal expansion was measured by Horizontal Dilatometer (DIL) and specific heat was measured by Differential Scanning Calorimeter (DSC). The heat absorbing properties of silica sand was investigated with thermal analysis. To measure the heat transport mechanism, two N-Type thermocouples were used in spherically shaped sand samples. Novel thermophysical characteristics were calculated based on the thermocouple recordings, which were then applied in the numerical simulation of heat distribution in the silica sand.