User manual

8 PBS-A03/A04-BA-e-1213
ρ =
A
A-B
o
ρ
ρ =
m
V
3 Principle of Density Determination
Three physical magnitudes are the volume and the mass of bodies as well as the
density of matter. In density mass and volume are related.
Density [ ρ ] is the relation of mass [ m ] to volume [ V ].
SI-unit of density is kilogram divided by cubic meter (kg/m³). 1 kg/m³ equals the density of
a homogenous body that, for a mass of 1 kg, has the volume of 1 m³.
Additional frequently applied units include:
1
g
cm
3
,
1
kg
m
3
,
1
g
l
The application of this density determination set in combination with the KERN PBS/PBJ
balances provides fast and safe determination of solids and fluids. Our set uses the
"Principle of Archimedes" to determine density:
BUOYANCY IS A FORCE. IT AFFECTS A BODY THAT IS IMMERSED INTO A FLUID. THE BUOYANCY
OF THE BODY EQUALS THE WEIGHT FORCE OF THE DISPLACED FLUID. THE FORCE OF
BUOYANCY ACTS VERTICALLY UPWARDS.
Thus, density is calculated according to the formulae below:
Determining density of solid bodies
Our balances enable weighing of solids in air [ A ] as well as water [ B ]. If the density of
the buoyancy medium is known [ ρ
o
] the density of the solid [ ρ ] is calculated as follows:
ρ = density of sample
A = weight of the sample in air
B = weight of sample in measuring fluid
ρ
o
= density of measuring fluid