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During the forging process for a steel sword, when the blacksmith places a hot iron blank into a cold bucket water A) The water molecules move faster.
The iron blank molecules are at a higher temperature and move faster than the water molecules, which are colder. When the blacksmith places the hot iron blank into the water bucket, heat is transferred from the hot iron blank to the cold water causing water molecules to move faster, as their temperature (and kinetic energy) increases. This is described by the Second Law of Thermodynamics.