When you drop an ice cube into a cup of hot cocoa, the particles of the cocoa begin to transfer heat to the ice cube. This causes the particles of the cocoa to lose energy and slow down, while the particles of the ice cube gain energy and speed up. As the ice cube melts, the particles of the cocoa continue to transfer heat to the water molecules that are forming, causing them to slow down and lose energy as well. The overall result is that the temperature of the cocoa decreases until it reaches equilibrium with the temperature of the surrounding environment. hope this helped