University:
North Idaho College
Course:
PHYS-211 | Engineering Physics I
Academic year:

2023
Views:

326

Pages:

4
Author:

Hani T.

Measurement of Surface Tension By Drop Weight Method. The weight of a drop of liquid falling from a capillary depends on the radius of the capillary and the surface tension of the liquid. The relationship between surface tension and the radius of the capillary is complex. However, this enables one to compare surface tension values of two liquids using the The same capillary. If γ for Liquid 1 is known, the surface tension for Liquid 2 can be estimated γ1 / γ2 = m1 / m2 Here m1 / m2 is the mass of, say, 10 drops of each liquid falling from the same height freely. The instrument used is known as a stalagmometer. Figure: A Stalagmometer A Capillary B Sometimes instead of the mass of liquid, the number of drops may also be determined. Liquids are sucked up a slightly above the mark A and allowed to drop from this mark for measurements, with the drops being counted. γ1 / γ2 = n2 * d1 / n1 * d2 where n2, n1 are the number of drops (for a given volume of liquid) and d1, d2 are the respective densities of the two liquids.