As mentioned above, α α κ κ T is one of the most common formulations for the thermal pressure coefficient. Both α α and κ κ T are affected by temperature changes, but the value of α α and κ κ T of a solid much less sensitive to temperature change above its Debye temperature. Thus, the thermal pressure of a solid due to moderate temperature change above the Debye temperature can be approximated by assuming a constant value of α α and κ κ T .