Ohaus Density Determination Kit Manual - Manual (Page 7)

Density Determination Kit EN-4
4 Density determination of solids
4.1 Fundamentals
The density of a solid is determined with the aid of a liquid whose density ρ
0
is known (water or ethanol are
usually used as auxiliary liquids). The solid is weighed in air (A) and then in the auxiliary liquid (B). The density ρ
can be calculated from the two weighings as follows:
ρ = Density of sample
A = Weight of sample in air
B = Weight of sample in the auxiliary liquid
ρ
0
= Density of the auxiliary liquid
ρ
L
= Air density (0.0012 g/cm
3
)
α = Balance correction factor (0.99985), takes air
buoyancy of the adjustment weight into account.
4.2 Performing the density determination of solids
Note: These instructions explain how to work with the density
determination kit. They describe the procedure for performing a density
determination manually.
If you need information about operating your balance, please refer to the
instruction manual provided with the balance.
For the density determination of solids, use the glass beaker (2) and one of
the two holders for solids which float (5) or sink (6). For certain OHAUS
1mg balances, use off setting weights according to your balance as
described in Section 1.2.
Prepare the balance for the density determination (install platform and
bracket) as described in Section 2.
Suspend the supplied thermometer (7) from the edge of the beaker (1).
Place the beaker on the platform and fill it with auxiliary liquid (liquid of
known density ρ
0’
usually distilled water or ethanol). Add enough liquid to
ensure the solid is covered by at least 1 cm liquid after immersion.
Suspend the suitable holder (5) or (6) for solids which float or sink from the
bracket (the adjacent illustration shows the holder for solid which sink).
Ensure that no air bubbles adhere to the immersed part of the holder
(Remove any air bubbles by moving the holder or by means of a fine
brush).
For certain OHAUS 1mg balances, place off setting weights on the holder
(the adjacent illustration shows the weights for EP/VP 1mg balances).
Close the draft shield doors and tare the balance.