What makes the water droplet assume the spherical shape and produce bubbles and foam? It is the surface tension of water. Surface tension is the measure of the cohesive force which is caused due to the attraction of particles in the surface layer by the liquid, to reduce the surface are to minimum.
The value of surface tension of water that is measure up to 4 significant figures is considered the standard value for adjustment of other devices. But a recent research has brought forward the fact that the value of water is not actually universal. Recently created pristine water has surface tension of a value that is approx. 25% more than that of the equilibrium value.
The question arises that why had it not been discovered until now? It is because pristine water has a life-span of less than a single millisecond. The technologies that were being used earlier were slow in response, which could have created problems in probing the microsecond system.
Such high values of surface tensions have also been reported earlier but the reports have remained controversial due to shortcoming and drawbacks.
Content Source: sciencebulletin.org