AND AD-1653, Инструкция по эксплуатации

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6
4.
ERROR FACTORS
There are several things that can affect the accuracy of a density measurement.
4.1. Buoyancy of Air
A density measurement is influenced by an upward force of 0.0010 to 0.0014 g/cm
3
(buoyancy of
air).
The density of air can be obtained by the equation below:
0.0012932 P (hPa)
d =
x
1 + 0.0036728 x t (°C) 1013.25
d : Density of air (g/cm
3
)
t : Air temperature (°C)
P : Atmospheric pressure (hPa)
When measurement accuracy of three significant digits is necessary, add 0.001 g/cm
3
to the
measured value to compensate for the error due to the air density.
4.2. Volume of Float
The tolerance of the measured value of the volume of the float is ±0.01 cm
3
.
In liquid density measurement, the decimal places beyond the second decimal place of the
measured value contain errors.
When measurement accuracy to the third decimal place or beyond is necessary, measure the
volume of the float using distilled water.
A - B
V = - 0.0035
ρ
- d
V : Volume of float (cm
3
)
A : Weight of float in air (g)
B : Weight of float in liquid (g)
ρ
: Density of distilled water at t°C (g/cm
3
)
d : Buoyancy of air at t°C (g/cm
3
)
0.0035 : Correction value for the wire (diameter of 1 mm) of the density pan
connecting the upper and lower pans (when the beaker provided
with this kit is used)