Answer:
The aluminum block will transfer heat to the water quickly, by conduction.
Explanation:
Aluminum is an excellent temperature conductor, which means that it can absorb heat very quickly, as well as transfer heat just as quickly. In this case, when the aluminum block is heated to 80ºC, the molecules in that block move quickly and start to collide with each other, releasing heat to the surrounding environment. When this aluminum bar comes in contact with water that has a temperature of 20ºC, the moving molecules of the aluminum bar release heat to the water that heats up, while the aluminum bar loses heat, decreasing its temperature. This temperature transmission will take place until the water and the aluminum bar have the same temperature