What is the difference between unit dry density and unit weight of soilds Γ_dry  vs Γ_solid?
Γ_{dry    =   Weight of soil solids / Total volume}  
Γ_{solid  =  Weight of soil solids / Volume of soil solids}

But dry weight of soil and weight of soil solid are the same. 

Γ_{solid is always greater than} Γ_dry.Why?

_{In case of}  Γ_{solid calculation only volume of soil solid is taken, which yields constant values where as} 

_In Γ_{dry Total volume is taken including Volume of voids, Volume of water present in pores,Volume of Soil solids. So the denominator value increases and so does the value of} Γ_dry.

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