Supplement - Sartorius YDK03 Instrucciones De Funcionamiento

Supplement

This supplement should help you to
better understand how the formulas and
allowance factors used here have been
derived�
Fundamental Principles
Mass (g)
Density =
Volume (cm
The Archimedean Principle:
A solid immersed in a liquid is exposed to
the force of buoyancy (G)� This value is the
same as that of the weight of the liquid
displaced by the volume of the solid�
The volume of an immersed solid V (s)
equals the volume of the displaced liquid
V (fl)�
The following are determined:
1� The weight of the sample in air: W (a)
2� The buoyancy of the solid in liquid: G
The specific gravity of a solid is:
sample mass
ρ = =
sample volume
If the density ρ (fl) of the displaced liquid
is known, then
Mass (fl)
V (fl) = =
ρ (fl)
Therefore:
W (a) · ρ (fl)
ρ =
G
20
3
)
W (a) W (a)
=
V (s)
V (fl)
G
ρ (fl)
Calculation
The specific gravity of a solid is calculated
from the ratio
ρ : W (a) = ρ (fl) : W (a) – W (fl),
where:
W (a) · ρ (fl)
ρ =
W (a) – W (fl)
W (a) – W (fl) = G =
buoyancy of the sample
The density of a liquid is determined from
the buoyancy of the plummet, which has
a defined volume
G
V (fl) =
V
where:
= specific gravity of a solid
ρ
ρ (fl) = density of the liquid
W (a) = weight of the solid in air
W (fl) = weight of the solid in liquid
G = buoyancy of the plummet
V = volume of the solid