if a substance is exposed to a source of heat then that substance may become hot / warm
warmth is not hotness. heat_of_solution is not heat. heat is what_makes_hot. when_water is heated_becomes_water_vapor. furnace is heat_source. heat is not what_makes_hot. heat_of_solution is heat. heating_element is heating_device. when_water is not heated_becomes_water_vapor. heat is not form_of_energy.