Mettler Toledo 33360 Mode D'emploi page 10

4.2 Determining the density of solids
- Use density determination kit for solids (= gem holder 6) 33360.
- Pour enough auxiliary liquid into beaker so that the solid body after being placed in wire basket of gem holder
will be covered with at least 10 mm of liquid. Insert thermometer. Place beaker on bridge 4 centrally located
below the suspension 7.
- Attach gem holder (watch for air bubbles, especially at the wire basket).
- Tare balance to read exactly zero.
- Place dry solid in upper cup of gem holder. Write down weight displayed by the balance (in grams or carats).
This is weight A of the solid when weighed in air.
- Again tare balance (with solid body in cup).
Balance display indicates exactly zero.
- Remove solid body from cup and place it in lower wire basket (in liquid).
Balance now displays buoyancy P of solid body (with minus sign in front).
Divide first indication A by second indication P, then multiply this intermediate result by the density ρ
auxiliary liquid (at the given temperature T).
The final result is density ρ
of the auxiliary liquid, e.g. g/ cm
ρ
o
A
= • ρ =
ρ
2 o
P
If the direct buoyancy reading is to be dispensed with, P can also be obtained from A - B. The balance will display
B instead of P if it has not been tared after result A was displayed or if it was tared with the solid body removed.
Example with buoyancy indication: Determining the density of a coin with the help of distilled water.
Measurement A = 3.011 g
values: P = 0.336 g
T = 25.5 °C →
The coin has a density of 8.93 g/ cm
8
of the solid body. The unit of measurement is the same as that used for density
2
(identical to g/ ml).
3
A [g]
• ρ [g/ cm ]
3
o
P [g]
= 0.997 g/ cm
ρ
o
.
3
Since the units of A an P cancel each other, the
weighing can be performed just as easily in carats
as in grams. Result ρ
2
measurement as result ρ
3.011
=
ρ
2
3 0.336
always has the same unit of
.
o
• 0.997 g/ cm = 8.93 g/ cm
3
METTLER TOLEDO 33360 + 210260
of the
0
3