The match stick placed on the metal block gets extinguished earlier

The metal block conducts the heat away from the burning point extinguishing the match stick

To magnify the mercury thread so that the mercury level is clearly seen.

Steam transfers more heat energy to the body than boiling water

Increases surface tension

Molecules decrease in kinetic energy hence less mobile.

The earthen jug has pores which allow water to diffuse / seep out and evaporate causing a cooling effect/ latent heat of evaporation causes cooling.

Air flowing above the capillary tube has a high velocity resulting in low pressure region atmospheric pressure push the water upward in the capillary tube

The sum of the vertically upward forces is equal to the sum of the vertically downward forces.