Question

1000 drops of water of same radius coalesce to form a larger drop. What happens to the temperature of the water drop? Why?

Answer 1

When the smaller water drops form a large and single water drop,the temperature decreases in that large and single water drop ,as compared with the sum of the temperature of all the smaller water drops.

Because,when the smaller drops merge with each other the total surface area decreases (because the large water drop is not a hollow sphere) and that's why the molecule amount in the surface area also decreases which ultimately decreases the heat retaining capacity of the surface layer of that large water drop.