Influencing Magnitudes And Error Sources - KERN EMB 200-3V Mode D'emploi


Determining density of liquids
The density of a fluid is determined with the help of a sinker providing a known
volume [ V ]. The sinker is weighed in air [ A ] as well as in the test fluid [ B ].
According to the Archimedes' Principle a body immersed in a fluid experiences a
force of buoyancy. [ G ]. This force equals the weight force of the fluid displaced by
the volume of the body.
The volume [ V ] of the immersed body equals the volume of the displaced fluid.
G = buoyancy of sinker
Buoyancy of sinker =
Weight of the sinker in air [ A ] - weight sinker in test liquid [ B ]
From this follows:
A-B
ρ =
V
ρ = density of test liquid
A = weight of sinker in air
B = weight of the sinkers in test liquid
V = volume of sinker*

8.1.1 Influencing magnitudes and error sources

 Air pressure
 Temperature
 Volume deviation of the sinker
 Surface tension of the liquid
 Air bubbles
 Immersion depth of the sample dish of sinker
 Porosity of the solid
18 EMB-V-BA-e-1422