Two floating objects are attracted to each other as the result of surface tension effects, irrespective of whether they are floating on water or on mercury. Explain why this is so.

Question

Accepted Answer

Because of the surface tension of the liquid, its height between the two objects is not the same as it is outside the objects; in the case of (a) water it is higher, whilst for (b) mercury (which has a negative angle of contact) it is lower.
Just above the liquid surface between the objects, the pressure has to be atmospheric in both cases and, correspondingly, just below the surface it has to be less than atmospheric for water and more than atmospheric for mercury. As can be seen from the figure this leads to net inward forces (acting on the shaded areas) in both cases and a tendency for the objects to move towards each other.

Question : Two floating objects are attracted to each other as the resu...

This Question has been Answered.

Already have an account?

Login