lämmön

Lämmön is the Finnish word for heat. Grammatically, lämmön is the genitive form of lämpö, used in compound phrases to refer to warmth or heat in a specific context, for example lämmön siirto (heat transfer) or lämmönvaraus (heat storage). In everyday language it can denote warmth or temperature in a general sense.

In physics, heat is the form of energy transfer between systems or bodies due to a temperature difference. It is not the same as temperature itself; pressure, volume and other factors influence how heat changes the state of a system. The SI unit of heat is the joule; heat flow rate is measured in watts.

Heat is transferred by three main mechanisms: conduction, convection, and radiation. Conduction occurs through materials by molecular interactions; convection by fluid movement; radiation by electromagnetic waves, which can occur in vacuum.

Thermodynamics treats heat as energy in transit obeying conservation of energy; the first law states that heat added to a system changes its internal energy or does work on the surroundings. In practice, accounting of heat is essential in heating, cooling, insulation, engines, and many industrial processes. The concept has evolved from early caloric ideas to modern statistical physics.