Why are the droplets of mercury when brought in contact pulled together to form a bigger drop? Also state with reasons whether the temperature of this bigger drop will be the same, or more, or less than the temperature of the smaller drop.

Explanation

Due to surface tension the liquid drop tends to have minimum surface area. When small mercury droplets are brought in contact, they form one drop due to strong force of cohension acting between molecules of mercury and surface tension. As the surface area of bigger drop is less than the surface area of small droplets, hence there is decrease in surface area when big drop is formed. As a result of it, the energy is lost by the big drop which appers as heat and hence temperature of big drop increases.