SPECIFIC GRAVITY. aka Relative Density. How specific is gravity anyway?. or How dense are your relatives?. What is Specific Gravity?. The density of any material is just its mass divided by its volume. It’s just the density of any material relative to (divided by) the density of water.
aka Relative Density
How specific is gravity anyway?
or How dense are your relatives?
The density of any material is just its mass divided by its volume
It’s just the density of any material relative to (divided by) the density of water
We measure the volume of any material by finding its mass in air and water
Archimedes figured out how to find the volume of any weird-shaped object…
In the lab we can weigh an object in air and then in water or use a pycnometer
and then calculate:
A = Oven dry mass of the sample (kilograms)
B = Mass of SSD sample in air (kilograms)
C = Mass of SSD sample in water (kilograms)
for specific gravity, divide density by the density of water...
the oven dried mass in air, PLUS
B - A
the mass of water in the water permeable voids
The volume excludes the water permeable voids:
A - C
and then calculate:
500.0 grams of SSD sample
A = Oven dry mass of the sample (grams)
B = Mass of the pycnometer + water (grams)
C = Mass of pycnometer + sample + water (grams)
The SSD mass of the sand or stone in air is thenMS + the mass of water absorbed, MWABS
Let the oven dried mass of the sand or stone (i.e., mass of solids in air) beMS
The Bulk Volume is the volume of solids VS +the volume of water absorbed VWABS
B = Mpyc + Mwcal
A = MS
C = Mpyc + Mwexcal + MS + MWABS
Mwcal – Mwexcal is the bulk volume of all the sand particles in the sample
Mass of water displaced by solids = B + A - C
Since this includes the volume of the water-permeable voids in all the sand particles,subtracting theMWABSwill leave the volume of the solid parts of the sand particles only
If masses are in grams and volumes in cm3, then
Also, given any 2 of the parameter values, the other 2 can be determined.
Example: If GASTM =2.605 & GAPPARENT = 2.718, find the GSSD and wa.
Basing the calculations on 100 g of oven dried material,