Problem Set #1 Q4

In Question 4, you have to calculate the bulk density of "a silty clay loam soil from the Fraser Valley in British Columbia (with a typical content of quartz and clay minerals for a mineral soil)" and has a porosity of 46%. When looking at the equations we were given in lecture, you see that the variable particle density is missing; without said variable you can't solve for bulk density. Is there a piece of information I'm missing from the hint about the soil being from the Fraser Valley and containing quartz/clay minerals?

It's a hint for particle density.

But what is the volume? it isn't given.

i had this question too... there seems to be no way to give an answer more specific then a range.

assuming the the density of quartz is around 2.65 g/cm³ i can give a good answer if its just quartz rocks and air, however the question wants to know for a typical content of clay minerals and quartz so i cant find a weight to do the question with.

but if we assume the (dry) bulk density of a mineral soil is normally about half that density, between 1.0 and 1.6 g/cm³, we can take 46% away from that to get 0.736g/cm³

otherwise just give the equation with the values you do know i guess..

As mentioned during lectures, mineral soils dominated by quartz and feldspar minerals (as specified in this question) have particle density of 2.65 g/cm3. Once you know the particle density and you are given porosity, you have all information needed to calculate bulk density. During lecture no.3, Sandra & I showed (ie wrote on the blackboard) what is the relationship among porosity (f), bulk density and particle density. Hence, check your lecture notes.