1 influencing magnitudes and error sources – KERN & SOHN EMB 500-1BE User Manual

Page 18

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EMB-V-BA-e-1422

18

ρ =

V

A-B

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:




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

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