Capillary length of water

In the Christmas vacation I was busy for reviewing some funding proposals. To my observation, there seemed too many research plans which strongly heads to industrial applications. Although such a direction is along the social demand, as a researcher in a basic science, it is somewhat pity. Indeed, only a few proposals mentioned theoretical directions…

The students were also busy to prepare their data for the presentations in IWEAYR-13 in Jeju. This event is the international workshop, in which top universities in Asian countries contribute. Taking this opportunity they will test themselves with the students from the other universities Asian wide.

Well, in the new years holiday, I found the interesting movie below. In this movie, what is discussed is to eliminate undesirable drips running down from the tip of the bottle for wines. The solution shown here is to make a groove at the tip of the bottle. According to the finding, the optimum groove is 2mm width and 1mm depth. These length scales are very interestingly close to the capillary length of water, which is ca. 2mm.