Problem $1[15$ Points$]$

$($a$)$ In Hydrometer test, we commonly do a few corrections to the readings we take off the Hydrometer stem.

First, discuss why we need these corrections. Second, list and discuss the common corrections we make

during a Hydrometer reading. $[5$ pts$]$

$($b$)$ Write Stokes' law and define all variables. Discuss, in short, how this law is useful in determining the grain

size distribution of fine$-$grained soils. $[5$ pts$]$

Assuming more than $90\%$ of the tested soil passed the U$.$S$.$ No$.200$ sieve, discuss the procedures and show

the calculation steps involved in determining the grain size distribution curve of this soil.

$($c$)$ At a given time of a Hydrometer test, let's say the observed reading was $40$ g$/$l$.$ What information is the

Hydrometer telling us$?[5$ pts