Hello-- Suppose that I insert a thin-needle thermometer into a porous material (such as snow) that consists of air, ice, and water. The thermometer is used to measure a temperature. Is it reasonable to assume that the temperature measured by the thermometer is the same as the temperatures of the air, ice, and water which are the constituents of the porous material? Now suppose that I insert another needle into the snow at a distance d0 from the thin-needle thermometer. An electric current is passed through the metal needle, which functions as a resistor. The needle heats up, and transfers thermal energy to the snow. Note once again that the snow is a mixture of air, ice, and water. Once again, I measure the temperature of this mixture using the thin-needle thermometer. Is it still reasonable to assume that the temperature measured using the thermometer is also the temperature of the air, ice and water? When I am writing this, I am thinking about the zeroth law of thermodynamics. Is my assumption reasonable, given this and other laws of thermodynamics?