KERN & Sohn GmbH
Ziegelei 1
D-72336 Balingen
E-Mail: info@kern-sohn.com
Phone: +49-[0]7433- 9933-0
Internet: www.kern-sohn.com
Operating instructions
PLS-A / PLJ-A, PLS-F / PLJ-F, PLE-N
KERN ALT-A02 / PLT A01
Version 1.0
01/2013
Fax: +49-[0]7433-9933-149
Set for density determination for analytical and
precision balances
KERN ALT-B,PLT-A, PLT-F, ALS-A / ALJ-A,
GB
ALT-A02/PLT-A01-BA-e-1310
PLJ-A, PLS-F / P LJ-F, PLE-N
KERN ALT-A02 / PLT A01
GB
Contents:
1 INTRODUCTION ............................................................................................................................ 3
1.1 SCOPE OF DELIVERY ................................................................................................................. 4
2 PRINCIPLE OF DENSITY DETERMINATION ............................................................................... 5
2.1 INFLUENCING MAGNITUDES AND ERROR SOURCES ...................................................................... 6
3 HOW TO PREPARE THE WEIGHING BALANCE ........................................................................ 7
4 INSTALLING THE DENSITY DETERMINATION SET .................................................................. 8
5 DENSITY DETERMINATION OF SOLIDS ................................................................................... 10
5.1 BALANCES WITH GRAPHIC DISPLAY (KERN ALT-B, PLT-A, PLT-F) .......................................... 13
5.2 BALANCES WITH LCD DISPLAY (KERN ALS-A / ALJ-A, PLS-A / PLJ-A, PLS-F / PLJ-F, PLE-N)
17
Version 1.0 01/2013
Operating instructions
Set for density determination for analytical and precision
balances KERN ALT-B,PLT-A, PLT-F, ALS-A / ALJ-A, PLS-A /
6 DETERMINING DENSITY OF LIQUIDS ...................................................................................... 20
6.1 BALANCES WITH GRAPHIC DISPLAY (KERN ALT-B, PLT-A, PLT-F) .......................................... 21
6.2 BALANCES WITH LCD DISPLAY (KERN ALS-A / ALJ-A, PLS-A / PLJ-A, PLS-F / PLJ-F, PLE-N)
25
7 PRECONDITIONS FOR PRECISE MEASUREMENTS............................................................... 28
7.1 CALCULATION OF RESULTS ..................................................................................................... 28
7.2 INFLUENCE FACTORS FOR MEASUREMENT ERRORS ................................................................. 28
7.2.1 Air bubbles ....................................................................................................................... 28
7.2.2 Temperature .................................................................................................................... 28
7.2.3 Solid matter sample ......................................................................................................... 29
7.2.4 Liquids .............................................................................................................................. 29
7.2.5 Surface ............................................................................................................................. 29
7.3 GENERAL INFORMATION .......................................................................................................... 29
7.3.1 Density / Relative Density ................................................................................................ 29
7.3.2 Drift of Balance Display ................................................................................................... 29
8 DENSITY TABLE FOR LIQUIDS ................................................................................................. 30
9 USER INSTRUCTIONS ................................................................................................................ 31
2 ALT-A02/PLT-A01-BA-e-1310
1 Introduction
The density sets ALT-A02 and PLT-A01 differ in the support of the weighing plate.
For the density set suitable for your balance, please refer to the following overview.
KERN ALT-A02 KERN PLT-A01
Set for density determinati o n for
analytical and precision balances
d= 0.1 mg / 1 mg
KERN ALT-B / PLT-A / PLT-F,
ALS-A / ALJ-A, PLS-A / PLJ-A,
PLS-F / PLJ-F,
PLE-N
• In order to guarantee a safe and trouble-free operation, please
read carefully the operating instructions.
• These operating instructions only describe the operation of the
density determinati on set . For further information on how to
operate your balance please refer to the operating instructions
supplied with each balance.
Set for density determinati o n for
precision balances
d= 10 mg
KERN PLT-A, PLT-F
PLS-A / PLJ-A,
PLS-F / PLJ-F
ALT-A02/PLT-A01-BA-e-1310 3
Thermometer
Sinker with storage box
Allen key
3.356g/cm3
1.1 Scope of delivery
Check packaging and density determination set immediately when unpacking for
possible visible damage.
Make sure that all parts are completely present.
Retainer of immersion basket Universal immersion basket for
floating and descending solid
matter
∅ 70 mm, 95 mm high
Retainer for sinker Glass beaker for density
determination „solid matter“
Platform for glass container
∅ 55 mm, 150 mm high
Glass beaker for
density determination „liquid“
4 ALT-A02/PLT-A01-BA-e-1310
ρ =
A
A-B
o
ρ
ρ =
m
V
1
g
cm
3
1
kg
m
3
1
g
l
2 Principle of Density Determinat ion
Three physical magnitudes are the volume and the mass of bodies as well as the
density of matter. In density mass and volume are related.
Density [ ρ ] is the relation of mass [ m ] to volume [ V ].
SI-unit of density is kilogram divided by cubic meter (kg/m³). 1 kg/m³ equals the
density of a homogenous body that, for a mass of 1 kg, has the volume of 1 m³.
Additional frequentl y applied units include:
, ,
The application of this density determination set in combination with the KERN
ABS/ABJ balances provides fast and safe determination of solids and liquids. Our set
uses the "Principle of Archimedes" to determine density:
BUOYANCY IS A FORCE. IT AFFECTS A BODY THAT IS IMMERSED INTO A LIQUID. THE
BUOYANCY OF THE BODY EQUALS THE WEIGHT FORCE OF THE DISPLACED LIQUID. THE
FORCE OF BUOYANCY ACTS VERTICALLY UPWARDS.
Thus, density is calculated according to the formulae below:
To determine the density of solid matter
Our balances enable weighing of solids in air [ A ] as well as water [ B ]. If the density
of the buoyancy medium is known [ ρo ] the density of the solid [ ρ ] is calculated as
follows:
ρ = Density of sample
A = Weight of the sample in air
B = Weight of the sample in the aid liquid
ρ
= Density of the aid liquid
o
ALT-A02/PLT-A01-BA-e-1310 5
ρ =
V
A-B
Determining density of liquids
The density of a liquid 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 liquid [ B ].
According to the Archimedes’ Principle a body immersed in a liquid experiences a
force of buoyancy [ G ]. This force equals the weight force of the liquid displaced by
the volume of the body.
The volume [ V ] of the immersed body equals the volume of the displaced liquid.
G = buoyancy of sinker
Buoyancy of sinker =
Weight of the sinker in air [ A ] - weight of sinker in test liquid [ B ]
From this follows:
ρ = density of sample liquid
A = weight of sinker in air
B = weight of the sinkers in test liquid
V = volume of sinker*
* If the volume of the sinker is unknown, this can be determined by a solid body
density measurement e.g. in water and be calculated as follows.
V = volume of sinker
A = weight of sinker in air
B = weight of sinker in water
ρ
= density of water
W
2.1 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 or of the sinker
Porosity of the solid
6 ALT-A02/PLT-A01-BA-e-1310
3 How to prepare the weighing balance
When the density set is installed, correct adjustment is not possible.
Perform necessary adjustment before installation of the density set using the
standard weighing plate.
If the balance is equipped with an internal adjustment weight (ALT / PLT, ALJ-A,
PLJ-A, PLJ-F) carry out an internal adjustment. After adjustment, enable “external
adjustment” in the adjus tme nt mo de me nu. This will avoid a request of an internal
adjustment, when the density set is installed.
If the balance is equipped with an external adjustment weight (ALS-A, PLS-A, PLS-
F, PLE-N) carry out an external adjustment.
For carrying out please refer to the operating instructions supplied with each balance
ALT-A02/PLT-A01-BA-e-1310 7
weighing plate.
4 Installing the density determin ation set
• When the density set is installed, correct adjustment is not possible.
• For reasons of adjustment, take away the density set and place the standard
Disconnect scale fr om power supply.
Remove the standard weighing plate acc. to fig.
Models ALT, ALS/ALJ Models PLE, PLS/PLJ, PLT; d = 0.1 mg - 1 mg
Models PLS/PLJ, PLT; d = 10 mg
8 ALT-A02/PLT-A01-BA-e-1310
Installed density set for solid matter „precision balances“
d= 10 mg
d = 0.1 mg - 1 mg
Install density determination set
(for solid matter please see chap. 5, for liquids see chap. 6)
Installed density set for solid matter “analytical balances”
ALT-A02/PLT-A01-BA-e-1310 9
5 Density determination of solids
For the determination of the density of solids, the solid is first weighed in air and then
in the aid liquid, whose density is known. From the weight difference results the
buoyancy from where the software calculates the density.
As aid liquid, usually distilled water or ethanol is used, see density table chapter 8.
Prepare balance as described in chapter 3 "Installation of density determination set".
Place the retainer of the immersion basket on the cone of the weighing plate.
Place the platform for glass containers in a way that it does not touch the
retainer of the immersion basket.
Place beaker in the centre of the platform Make sure that it has no contact with
the retainer or with the immersion basket.
Hang the immersion basket on the retainer. Make sure that it is centred in the
recess.
Fill the aid liquid into a glass beaker. Fill in so much liquid that the solid matter
after immersion remains at least 1 cm under the liquid level. Immerse
thermometer
Bring aid liquid / instruments / sample to the right temperature until you
achieve a constant temperature. Observe the warm-up time of the balance.
Connect balance to power supply, the balance will carry out a self-test. Switch
on using the ON/OFF button and wait until the gram display appears.
10 ALT-A02/PLT-A01-BA-e-1310
d > 1 g /cm3
For descending solid matter suspend the immersion basket as shown in fig. 1.
Liquid
Fig. 1
For determination of density of solid matter, the universal immersion basket for
floating (d > 1 g /cm3) and descending solid matter (d < 1 g /cm3) must be used.
ALT-A02/PLT-A01-BA-e-1310 11
d < 1 g /cm3
!
If the buoyancy of the sample is so much that the immersion basket is lifted, place
weighing in air.
For floating solid matter suspend the immersion basket as shown in fig. 2.
Fig. 2
Liquid
At solid material with density less than 1 g/cm3, a density determination with two
different methods is pos si bl e.
Method 1:
As aid liquid is used a liquid with less density than that of the solid material, e.g.
ethanol approx. 0.8 g/cm3.
This method should be applied when the density of the solid is just slightly
different from that of the distilled water.
Using ethanol is not recommended, when the solid material is being attacked.
When working with ethanol, you must observe the applicable safety
regulations.
Method 2:
Here the sample is not placed upon, but under the sample dish. For that purpose
the sample dish of the immersion basket must be assembled upside down as
shown in fig. 2 with the help of the delivered Allen key.
an additional weight on it in the upper sample dish and tare it away when
12 ALT-A02/PLT-A01-BA-e-1310
5.1 Ba lances with graphic display (KERN ALT-B, PLT-A, PLT-F)
In weighing mode press MENU button. The master menu will be displayed.
Use the navigation buttons to select the menu item „Density“.
Acknowledge using PRINT button, the current setting is displayed.
Use the navigation buttons to select setting „Solid body“.
Confirm using the PRINT button, the set density of the aid liquid is displayed
(factory setting 1.0000 g /cm3 for distilled water at 20°C).
To change (see table chap. 8) press the TARE button.
To delete keep pressed the TARE button. Use the navigation buttons to
increase/reduce the digit. Use the TARE button to select the next digit. Repeat
this sequence for each digit.
Confirm entry with PRINT button, the display for calculation of „Weight in air“ is
displayed.
Should the balance not show Zero, press the TARE button.
ALT-A02/PLT-A01-BA-e-1310 13
Sample
Place sample in the upper sample dish.
Wait for stability display [ ], then take over the weight value using the PRINT
button.
14 ALT-A02/PLT-A01-BA-e-1310
Sample
Wait until the display for determination of „sample in aid liquid“ appears. Remove
the sample and if required tare by using the TARE button.
Lay the sample into the lower sample dish and immerse it in the aid liquid trying
to avoid bubble formation.
Make sure that the sample is at least 1 cm immersed.
Wait for stability display [ ], take over the weight value using PRINT button. The
density of the sample is shown.
ALT-A02/PLT-A01-BA-e-1310 15
If at the density determination errors have appeared, „d-----„ is displayed.
When an optional printer is connected, the displayed value can be edited using
the PRINT button.
Printout example (KERN YKB-01N):
07-09-11 11:14:57
d : 8.0700 g/cm3
For further measurements go back to density determination mode, press MENU
button.
Back to weighing mode, press ON/OFF button.
16 ALT-A02/PLT-A01-BA-e-1310
5.2 Ba lances with LCD display (KERN ALS-A / ALJ-A, PLS-A / PLJ-A, PLS-F / PLJ-F, PLE-N)
In weighing mode press MENU button. The first menu item „count“ is displayed.
Press MENU button
Acknowledge using PRINT button, the current setting is displayed.
Using MENU button select „d SoLid“
Confirm by pressing the PRINT button. The currently set density of the aid liquid
is displayed (factory setting 1.0000 g /cm3 for distilled water at 20°C).
To change, enter the density of the aid liquid using arrow keys .
Confirm input by pressing the PRINT button.
ALT-A02/PLT-A01-BA-e-1310 17
], then take over the weight value „sample in air“ using
Sample
The display for weight determination of the "sample in air“ appears.
Confirm by pressing the PRINT button.
Should the balance not show Zero, press the TARE button.
Lay the solid matter in the upper sample dish.
Wait for stability display [
the PRINT button.
Wait until the display for weight determination of „sample in aid liquid“ appears.
Confirm by pressing the PRINT button.
Remove the sample and if required tare by using the TARE button.
18 ALT-A02/PLT-A01-BA-e-1310
If at the density determination errors have appeared, „d-----„ is displayed.
Sample
Lay the sample into the lower sample dish and immerse it in the aid liquid trying
to avoid bubble formation.
Make sure that the sample is at least 1 cm immersed.
Wait for stability display [ ], then take over the weight value „sample in aid
liquid“ using the PRINT button. The density of the sample is shown.
When an optional printer is connected, the displayed value can be edited using
the PRINT button.
Printout example (KERN YKB-01N):
d : 2.0000 g/cm3
Return to weighing mode
Press the ON/OFF button
or use the MENU button to start a new measuring cycle.
ALT-A02/PLT-A01-BA-e-1310 19
6 Determining density of liquids
At the density determination of liquids, a glass sinker is used whose density is
known. The glass sinker is weighed first in air and then in the liquid whose density is
to be determined. From the weight difference results the buoyancy from where the
software calculates the density.
Prepare balance as described in chapter 3 "Installation of density determination set".
Place the retainer of the immersion basket on the cone of the weighing plate.
Place the platform for glass containers in a way that it does not touch the
retainer of the immersion basket.
Place a high glass beaker in the centre of the platform. Suspend thermometer.
Keep the sinker ready
Bring test liquid / instruments / sinker to the right temperature until you achieve
a constant temperature. Observe the warm-up time of the balance.
Connect the balance to the power supply, the balance carries out a self-test.
Switch on by the ON/OFF button and wait until the gram display appears.
20 ALT-A02/PLT-A01-BA-e-1310
3.1000g/cm3
6.1 Ba lances with graphic display (KERN ALT-B, PLT-A, PLT-F)
In weighing mode press MENU button. The master menu will be displayed.
Use the navigation buttons to select the menu item „Density“.
Acknowledge using PRINT button, the current setting is displayed.
Use the navigation buttons to select the setting „Liquid“.
Confirm using the PRINT button, the currently set density of the sinker is
displayed (factory setting 3.0000 g/cm3).
Read off the density of the sinker on the storage box and enter it. To delete keep
pressed the TARE button. Use the navigation buttons to increase/reduce the
digit. Use the TARE button to select the next digit. Repeat this sequence for
each digit.
Confirm by pressing the PRINT button. The display for weight determination of
the "Sinker in air“ appears.
If weighing balance does not show Zero, press TARE.
ALT-A02/PLT-A01-BA-e-1310 21
Attach the sinker.
Wait for stability display [ ], take over the weight value using PRINT button
Wait until the display for weight determination of „sinker in test liquid“ appears.
Remove the sinker and if required tare by using the TARE button.
Fill the glass beaker with test liquid
22 ALT-A02/PLT-A01-BA-e-1310
If possible, immerse the sinker bubble-free in the test liquid.
Make sure that the sinker is at least 1 cm immersed.
Wait for stability display [ ], take over the weight value using PRINT button. The
density of the test liquid is shown at the temperature displayed by the
thermometer.
ALT-A02/PLT-A01-BA-e-1310 23
If at the density determination errors have appeared, „d-----„ is displayed.
07-09-11 11:14:57
0.9748 g/cm3
When an optional printer is connected, the displayed value can be edited using
PRINT.
Printout example (KERN YKB-01N):
d :
For further measurements go back to density determination mode, press MENU
button.
Back to weighing mode, press ON/OFF button.
24 ALT-A02/PLT-A01-BA-e-1310
3.1000g/cm3
6.2 Ba lances with LCD display (KERN ALS-A / ALJ-A, PLS-A / PLJ-A, PLS-F / PLJ-F, PLE-N)
In weighing mode press MENU button. The first menu item „count“ is displayed.
Press MENU button
Acknowledge using PRINT button, the current setting is displayed.
Using MENU button select „d Liquid“
Confirm using the PRINT button, the currently set density of the sinker is
displayed (factory setting 3.0000 g/cm3).
Read off and enter the density of the sinker on the storage box or suspension
bracket. To delete keep pressed the TARE button. Use the navigation buttons
to increase/reduce the di g i t. Use the TARE button to select the next digit . Repeat
this sequence for each digit.
ALT-A02/PLT-A01-BA-e-1310 25
Confirm input by pressing the PRINT button. The display for weight
determination of the "Sinker in air“ appears.
Confirm by pressing the PRINT button.
If weighing balance does not show Zero, press TARE.
Attach the sinker centrically.
Wait for stability display [ ], take over the weight value „sinker in air“ using the
PRINT button.
Wait until the display for weight determination of „sinker in test liquid“ appears.
Confirm by pressing the PRINT button.
Remove the sinker and if required tare by using the TARE button.
Fill the glass beaker with test liquid
26 ALT-A02/PLT-A01-BA-e-1310
If at the density determination errors have appeared, „d-----„ is displayed.
If possible, immerse the sinker bubble-free in the test liquid.
Make sure that the sinker is at least 1 cm immersed.
Wait for stability display [ ], take over the weight value „sinker in test liquid“
using the PRINT button. The density of the test liquid is shown at the
temperature displayed by the thermometer.
When an optional printer is connected, the displayed value can be edited using
the PRINT button.
Printout example (KERN YKB-01N):
d: 2.0000 g/cm3
Return to weighing mode
Press the ON/OFF key
or use the MENU button to start a new measuring cycle.
ALT-A02/PLT-A01-BA-e-1310 27
ρ =
A
A-B
o
ρ
7 Preconditions for Precise Measurements
There are numerous error possibilities during density determination.
Accurate knowledge and caution are required to achieve precise results when
applying this density set in combination with the balance.
7.1 Ca lculation of Results
The balance displays results for density determination by giving four decimal places.
However, this does not mean that the results are accurate down to the last decimal
place as this would be the case for a calculated value. Therefore all weighing results
used for calculations have to be examined closely.
Example for density determination of solids:
To ensure high-grade results, numerators as well as common denominators of the
formula below must show the desired accuracy. If either of them is instable or flawed,
the result, too, will be instable or flawed.
ρ = Density of sample
A = Weight of the sample in air
B = Weight of the sample in the aid liquid
ρ
= Density of the aid liquid
o
7.2 Influence Factors for Measurement Errors
7.2.1 Air bubbles
A small bubble with a diameter of 1 mm results in a buoyancy of 0.5 mg, while those
with 2 mm Ø already produces a buoyancy of 4 mg.
Therefore, make sure that no air bubbles adhere on the solid object or sinker that is
immersed in the liquid.
An oily surface causes air bubbles when immersing in the liquid, so
remove grease from solvent resistant solid matter sample
clean all parts that are immersed regularly and don't touch them with bare
fingers
Don't lay solid samples (particularly flat objects) outside of the liquid on the sample
bowl, because this results in air bubbles by the joint immersion.
7.2.2 Temperature
Normally solid matter is insensitive to temperature changes, therefore the respective
changes of density can be ignored. Nevertheless the temperature of the liquid used
for density determination of solid matter must be taken into consideration as any
temperature change by one degree °C causes a change of density from 0.1 to 1%.
This has an effect on the third decimal point of the result.
28 ALT-A02/PLT-A01-BA-e-1310
7.2.3 Solid matter sample
A sample possessing too great a volume that is immersed in liquid will result in an
increase in liquid level inside the glass pitcher. As a result, part of the suspension
bracket of the sample dish will also be immersed causing buoyancy to increase. As a
consequence the weight of the specimen in the liquid will drop.
Samples that change the volume or assimilate liquid are unsuitable for measurement.
7.2.4 Liquids
Solids are generally not sensitive to temperature changes, so that the corresponding
density changes are not rel ev ant . However, since you work with an aid liquid by the
density determination of solids, according to the "Archimedean Principle", its
temperature is taken into account. The temperature change effects liquids greater
and causes changes in the density in order of 0.1 to 1 ‰ per °C. Hereby, the third
digit after the decimal point is affected.
7.2.5 Surface
The suspension bracket of the sample dish penetrates the surface of the liquid. This
state undergoes continuous change. If the sample or the sinker is relatively small, the
surface tension will impair repeatability. Adding a small amount of tenside (detergent)
makes surface tension negligible and increases reproducibility.
7.3 G eneral information
7.3.1 Density / Relative Density
Relative density follows from the weight of a specimen divided by the weight of water
(at 4° Celsius) of the same volume. For this reason relative density does not have a
unit. Density equals mass divided by volume.
The application of the relative density instead of the density of a liquid in a formula
produces an incorrect result. In the case of liquids only their density is
physically meaningful.
7.3.2 Drift of Balance Display
The drifting of a balance does not influence the final result of the density
determination although the shown weight of weighing in air is affected. Accurate
values are merely required if the density of liquids is determined by means of a
sinker.
When changing the ambient temperature or location, an adjustment of the balance is
necessary. For this purpose, remove the density set and carry out adjustment using
the standard weighing pan.
ALT-A02/PLT-A01-BA-e-1310 29
Temperature
Density ρ [g/cm
3
]
Water
Ethyl alcohol
Methyl alcohol
10
0.9997
0.7978
0.8009
11
0.9996
0.7969
0.8000
12
0.9995
0.7961
0.7991
13
0.9994
0.7953
0.7982
14
0.9993
0.7944
0.7972
15
0.9991
0.7935
0.7963
16
0.9990
0.7927
0.7954
17
0.9988
0.7918
0.7945
18
0.9986
0.7909
0.7935
19
0.9984
0.7901
0.7926
20
0.9982
0.7893
0.7917
21
0.9980
0.7884
0.7907
22
0.9978
0.7876
0.7898
23
0.9976
0.7867
0.7880
24
0.9973
0.7859
0.7870
25
0.9971
0.7851
0.7870
26
0.9968
0.7842
0.7861
27
0.9965
0.7833
0.7852
28
0.9963
0.7824
0.7842
29
0.9960
0.7816
0.7833
30
0.9957
0.7808
0.7824
31
0.9954
0.7800
0.7814
32
0.9951
0.7791
0.7805
33
0.9947
0.7783
0.7896
34
0.9944
0.7774
0.7886
35
0.9941
0.7766
0.7877
8 Density Table for Liquids
[°C]
30 ALT-A02/PLT-A01-BA-e-1310
9 User Instructions
• T o form a reproducible mean value several density measurement are necessary
• Remove fat from solvent-resistant sample / /glass sinker /beaker.
• Regularly clean sample dishes/glass sinker/glass beaker, do not touch immersing
part with your hands
• Dry sample/glass sinker/pincers after each measurement.
• Adjust sample size to sample dish (ideal sample size > 5 g).
• Only use distilled water.
• When immersing for the first time, lightly shake sample dishes and sinker, in order
to dissolve air bubbles.
• Always ensure that, when re-immersing into the liquid no additional bubbles
adhere; it is better to use pincers to place the sample.
• Remove firmly adherent air bubbles with a fine brush or a similar tool.
• T o avoid adherent air bubbles smoothen samples with rough surface.
• T ake care that no water drips onto the upper sample dish when weighing with the
help of tweezers.
• In order to reduce the surface tension of water and the friction of the liquid on the
wire, add three drops of a common detergent (washing-up liquid) to the
measuring liquid (density modification of distilled water occurring due to the
addition of tensides can be ignored).
• Oval samples can be held more easily with pincers when you cut grooves into
them.
• T he density of porous solids may only be determined approximately. Buoyancy
errors occur when not all the air is eliminated from the por es dur i ng immer si on in
the measuring liquid.
• T o avoid great vibrations of the balance, place sample carefully.
• Avoid static charge, e. g. dry glass sinker with cotton cloth only.
• If the density of your solid only deviates slightly from that of disti ll ed water, ethanol
may be used as measuring liquid. However, check beforehand whether the
sample is solvent-proof. In addition you must observe the applicable safety
regulations when working with ethanol.
• Handle glass sinker with care
(no warranty claims in case of damage).
• To avoid corrosion, don't leave the density set immersed in liquid for a long time.
ALT-A02/PLT-A01-BA-e-1310 31
Loading...