▁allows ▁its ▁use ▁in ▁a ▁small ▁volume ▁of ▁liquid ▁with ▁ 5 0 ▁l ▁samples ▁being ▁used ▁in ▁some ▁devices . ▁ ▁In ▁addition , ▁the ▁rod ▁also ▁allows ▁use ▁for ▁the ▁Wil hel my ▁method ▁because ▁the ▁rod ▁is ▁not ▁completely ▁removed ▁during ▁measurements . ▁ ▁For ▁this ▁the ▁dynamic ▁surface ▁t ension ▁can ▁be ▁used ▁for ▁accurate ▁determ ination ▁of ▁surface ▁k inet ics ▁on ▁a ▁wide ▁range ▁of ▁times cal es . ▁ ▁The ▁P add ay ▁technique ▁also ▁offers ▁low ▁operator ▁variance ▁and ▁does ▁not ▁need ▁an ▁anti - v ibration ▁table . ▁ ▁This ▁advantage ▁over ▁other ▁devices ▁allows ▁the ▁P add ay ▁devices ▁to ▁be ▁used ▁in ▁the ▁field ▁easily . ▁ ▁The ▁rod ▁when ▁made ▁of ▁composite ▁material ▁is ▁also ▁less ▁likely ▁to ▁b end ▁and ▁therefore ▁che aper ▁than ▁the ▁more ▁cost ly ▁plat in um ▁rod ▁offered ▁in ▁the ▁du ▁No ü y ▁method . ▁ ▁In ▁a ▁typical ▁experiment , ▁the ▁rod ▁is ▁lower ed ▁using ▁a ▁manual ▁or ▁automatic ▁device ▁to ▁the ▁surface ▁being ▁analyz ed ▁until ▁a ▁men is cus ▁is ▁formed , ▁and ▁then ▁raised ▁so ▁that ▁the ▁bottom ▁edge ▁of ▁the ▁rod ▁lies ▁on ▁the ▁plane ▁of ▁the ▁und ist urbed ▁surface . ▁ ▁One ▁dis adv antage ▁of ▁this ▁technique ▁is ▁that ▁it ▁can ▁not ▁b ury ▁the ▁rod ▁into ▁the ▁surface ▁to ▁measure ▁inter fa cial ▁t ension ▁between ▁two ▁liqu ids . ▁ ▁Pract ical ▁uses ▁ ▁The ▁practical ▁uses ▁of ▁an ▁instrument ▁that ▁uses ▁a