Question

In a hydrometer test, soil used should be dispersed first in order to eliminate particle coagulation.

(a) True

(b) False

I got this question in final exam.

My question is from Grain Size and Shape in section Molding and Core Sands of Casting-Forming-Welding I

Answer 1

Right choice is (a) True

The explanation is: For the analysis of small size grains of soils in hydrometer test, soil sample used should be dispersed first in order to eliminate the particle coagulation. This is mainly accomplished by blending of soil with the solution of sodium hexametaphophate and then stirring is done to get a proper uniform solution.