GXA-13

1WMPD4003565A

Density Determination Kit© 2017 A&D Company, Limited. All rights reserved.
No part of this publication may be reproduced, transmitted, transcribed, or translated
into any language in any form by any means without the written permission of A&D
Company, Limited.

The contents of this manual and the specifications of the instrument covered by thismanual are subject to change for improvement without any notice and obligation on
the part of the manufacturer.

Contents
1.
1.1.

Introduction ............................................................................................................................................2
Precautions .......................................................................................................................................22.

Packing List ...........................................................................................................................................3

3.
3.1.
3.2.
3.3.
3.4.
3.5.

Density Measurement Principle ...........................................................................................................4
Density ..............................................................................................................................................4
Specific Gravity .................................................................................................................................4
Density Measurement Principle ......................................................................................................4
Density of a Solid..............................................................................................................................4
Density of a Liquid ............................................................................................................................4

4.1.
4.2.
4.3.
4.4.
4.5.
4.6.

Error Factors..........................................................................................................................................5
Buoyancy of Air.................................................................................................................................5
Temperature of a Liquid ...................................................................................................................5
Volume of Float.................................................................................................................................5
Influence of Wire...............................................................................................................................5
Surface Tension................................................................................................................................6
Bubbles .............................................................................................................................................64.

5.

Measuring the Density of a Solid .........................................................................................................8
5.1.
Assembling the Kit............................................................................................................................8
5.1.1.
Assembling the Kit Using Glass Breeze Break (GXA-10) .......................................................9
5.2.
Measuring the Density of a Solid...................................................................................................10
5.2.1.
Density of Water........................................................................................................................10

6.

Measuring the Density of a Liquid...................................................................................................... 11
Assembling the Kit.......................................................................................................................... 11
Measuring the Density of a Liquid ................................................................................................. 11

6.1.
6.2.
7.

Density Measurement Using the GX-A／GF-A Balance ...............................................................127.1.1.
Preparation Before Measurement (Settings of the Function Table） ...................................127.1.2.
Measuring Solid Density (Specific Gravity), Function Table.......................................14
7.1.3.
Specifying Liquid Density .........................................................................................................15
7.1.4.
Measuring Liquid Density (Specific Gravity), Function Table......................................16
7.1.5.
Specifying Volume of Float.......................................................................................................17

8.

Frequently Asked Questions and Answers .......................................................................................18

1

1. Introduction
Thank you for your A&D purchase! This is the instruction manual for the density determination kit.
The density determination kit can be easily used to measure the density of solid or liquid when it iscombined with the following electronic balances.
GX-203A, GX-303A, GX-403A, GX-603A, GX-1003A, GX-1603A,
GF-203A, GF-303A, GF-403A, GF-603A, GF-1003A, GF-1603A
Before using the density determination kit, please read this instruction manual thoroughly.

1.1.

Precautions

This density determination kit allows the density or specific gravity of a solid or liquid to be measured.
However, the results of measurements may be affected by various factors that could cause errors,
therefore we cannot guarantee them to be 100 % accurate.
Do not use the density determination kit for measuring the density of chemically active substances.
After using the density determination kit, clean all surfaces to remove rust and oxides.
The balance is precision instrument, so avoid shocks or excessive loads.
To improve measuring accuracy, allow the temperature of liquid (water) and sample (solid) toequalize to the ambient room temperature and perform measurement in a stable environment.
The breeze break provided with the balance cannot be used with the density determination kit.
To perform an accurate density measurement, use the glass breeze break available as an option( GXA-10).

2

2. Packing List
φ0.2

Float

Wire

Float hook

Thermometer

Density pan stand

Beaker stand

Beaker

Thermometer clamp

Density pan

Beaker stand spacer 2 pieces

Kit box3

Tweezers

3. Density Measurement Principle
3.1.

DensityDensity means the amount of mass of a sample per unit volume. ( Unit [g/cm3] and others )M
M: Mass [g]V: Volume [cm3]ρ =ρ: Density [g/cm3]
V

3.2.

Specific Gravity

Specific gravity means the ratio of the density of a sample to the density of pure water (with thesame volume as that of the sample) at 4 °C at 1013.25 hPa.
Mρ =ρ: Specific gravity [ No unit ] M: Mass [g]V: Volume [cm3]V•ρ43
ρ4: Density of water at 4 [°C], 0.99997 [g/cm ] 1.000 [g/cm3]

3.3.

Density Measurement Principle

The GXA-13 combined with an authorized balance can measure the density of a sample based on
the Archimedes’ principle.
Archimedes’ Principle of Density Measurement
A body immersed in a liquid (gas) is subject to an upward force equal to the weight of theliquid (gas) it displaces. The upward force is buoyancy.

3.4.

Density of a Solid

The density of a solid can be obtained according to the sample weight in air, sample weight in liquid
and the density of the liquid.
A
ρ =
×ρ0
ρ: Density of sample [g/cm3]
A: Sample weight in air [g]A-B
3
B: Sample weight in liquid [g]ρ0: Density of liquid [g/cm ]3.5.

Density of a Liquid

The density of a liquid can be obtained according to the weight of the float in air, the weight of thefloat in a liquid, and the known volume of the float.
A-B
ρ =
+d
ρ: Density of liquid [g/cm3]
A: Weight of the float in air [g]V3
V: Volume of the float [cm ]B: Weight of the float in liquid [g]d: Density of air ( approximately 0.001 [g/cm3] )4

4. Error Factors
There are several error factors that may affect the accuracy of a density measurement.

4.1.

Buoyancy of Air

When the liquid density is measured, an upward force, 0.0010 to 0.0014 [g/cm3], is exerted inproportion to the volume of the liquid. The buoyancy in air per 1 [cm3] is found by:
0.0012932
P
t: Air temperature [°C]d=×d: Air density [g/cm3]
1+0.0036728×t
1013.25
P: Air pressure [hPa]
When obtaining measurement results down to the third decimal place, 0.001 [g/cm3] is added tothe measured value to compensate for an error in air density.

4.2.

Temperature of a Liquid

When taking a density measurement using a liquid, the density measurement will change depending on
the temperature. Obtain the density of a liquid by comparing its temperature with the values in "Table 1
Temperature and Density of Water" for distilled water or provided in other reference documents forother liquids.

4.3.

Volume of Float

The tolerance of the measured value of the volume of the float is ±0.01 [cm3].

4.4.

Influence of Wire

When a solid sample is placed on the density pan for measurement, which is immersed in a liquid,
the liquid surface position rises. At this time, the wire (1 mm) connecting the upper and lower pans
is subject to the buoyancy whose magnitude is equal to the weight of the raised liquid. 1 mm raise of
the liquid surface exerts a buoyancy of approx. 0.8 mg to the wire. To minimize a measurement error
caused by the buoyancy, adjust the sample size so that it will not raise the liquid surface, or perform
a mathematical correction.
When measuring the density of a liquid, the float-suspending wire (2 mm) immersed in the liquid
affects the measurement. Immersing the wire by 10 mm exerts a buoyancy of approx. 0.3 mg to thewire. However, this buoyancy can be ignored because it is divided by the volume of the float when
the density of the liquid is obtained.

5

4.5.

Surface Tension

When the density of a solid is measured, a force of approx. 5 mg (surface tension) is applied to thedensity pan, between the wire (1 mm) of the density pan and the surface of the liquid.
The surface tension can be reduced to approx. 1 mg by adding a surfactant (for example, a water
droplet preventive solution as used for developing photographs). Adding 0.1 mL (1.2 [g/cm3]
density) of a surfactant to 200 mL of water will increase the density of the water by approx. 0.0001[g/cm3].
When the density of a liquid is measured, a force of about 1 mg is exerted by the wire of 0.2 mm indiameter. However, this force can be ignored because it is divided by the volume of the float.

4.6.

Bubbles

The buoyancy of a bubble of 1 mm in diameter is approx. 0.5 mg. Stickiness of bubbles depends on
the shape and material of a sample. Make measurements considering the characteristic of bubbles.
When the density of a solid is measured, we recommend adding a surfactant to reduce the influenceof surface tension and bubbles.

67

5. Measuring the Density of a Solid
5.1.

Assembling the Kit
LiquidStep 1. Remove the weighing pan and breeze breakfrom the balance.

Step 5.

Step 4.

Step 2. Put the density pan stand on the pan support.
Beaker
Step 3. Place the spacer under the legs of the
beaker stand so that the legs fit to the ditch of
the spacer.
Put the beaker stand on the balance as suchthat it will not touch the density pan stand.

Thermometer
Thermometer clamp
Beaker standDensity pan
Step 6.

Step 5.
Step 3.
Spacer toprevent slipping

Step 4. Attach the thermometer clamp to beaker.
Insert the thermometer into the clamp.

Density pan standWeighing pan

Step 2.

Step 5. Pour a liquid (distilled water, etc.), whose
specific gravity is known, into the beaker.
Put the beaker on the beaker stand.

Step 1.

Step 6. Place the density pan on the density pan stand.
Step 7. Adjust the amount of the liquid so that sample
is approximately 10 mm under the surface ofthe liquid when the sample is put on the lower
pan of the density pan in the liquid.

Step 7. Adjust liquid surface.
Approx. 10 mm
SampleLower pan

Step 8. Press the RE-ZERO key to display
zero after the weighed value stabilized.
All preparations are complete.
If the weighing value is unstable due to breeze
and vibration, etc., increase the parameter of"Condition ()" in the function table or
use the breeze break.

8

Pan support

5.1.1. Assembling the Kit Using Glass Breeze Break (GXA-10)
Step 1. Remove the weighing pan from the balance.
Step 2. Place the breeze break on the balance andperform the procedures from step 2 to step
8 on the last page.
All preparations are complete.
If the weighing value is unstable due to breeze
and vibration, etc., increase the parameter of"Condition ()" in the function table or
use the breeze break.

9

5.2.

Measuring the Density of a Solid

The density of a solid can be obtained by averaging the measured values.
Display example is GX-6002A.
Step 1. Start the measurement after the watertemperature becomes stable.

Step 2.

Step 3. Sample

Step 2. Press the RE-ZERO key to display zero.
Step 3. Put sample on the upper pan of the density pan
and record the measurement value A in air.
Step 4.

Step 4. Press the RE-ZERO key to display zero.
Put the sample on the
Step 5. Put sample on the lower pan of the density pan
lower pan after step 4.
and record measurement value B in liquid.
Step 5. Adjust liquid surface.
Adjust the amount of the liquid so that
Approx. 10 mmsample is approximately 10 mm under the
Sampleliquid surface when the sample is put on
Lower panlower pan in the liquid.
Step 6. Obtain the water density using the water temperature and"Table-1, temperature and density of water". Acquire liquid density
using the following formula substituted the measured value.
ρ : Calculated sample density [g/cm3]
A
ρ =
x ρ0
ρ0 : Water density [g/cm3]|B|
A : Measurement value in air [g]B : Measurement value in water [g]Example of recording sheet and calculation (3 significant figures).

Measurement value
Measurement value
4.810 [g]0.595 [g] Water temperature 26 °C
in air A
in water B
Water density ρ0 0.99678 [g/cm3]
Calculated sample density ρ
8.06 [g/cm3]
4.810
x 0.99678 = 8.06 [g/cm3]| 0.595 |5.2.1. Density of Water
At sea level (1 atmosphere pressure), the density of water reaches a maximum at 3.98 [°C].
Table 1, Temperature and Density of Water
°C
0
10
20
30
40

Unit: g/cm3

+0
+1
+2
+3
+4
+5
+6
+7
+8
+9
0.99984 0.99990 0.99994 0.99996 0.99997 0.99996 0.99994 0.99990 0.99985 0.99978
0.99970 0.99961 0.99949 0.99938 0.99924 0.99910 0.99894 0.99877 0.99860 0.99841
0.99820 0.99799 0.99777 0.99754 0.99730 0.99704 0.99678 0.99651 0.99623 0.99594
0.99565 0.99534 0.99503 0.99470 0.99437 0.99403 0.99368 0.99333 0.99297 0.99259
0.99222 0.99183 0.99144 0.99104 0.99063 0.99021 0.98979 0.98936 0.98893 0.98849
10

6. Measuring the Density of a Liquid
6.1.

Assembling the Kit

Assemble the kit as described in the procedure below.

The volume of the float is
stamped on the hook.
Ex. 10.01 cm3

Step 1. Refer to "5.1. Assembling the Kit" up toassembling the beaker stand.

Step 4.
Length is approximately 50 mm

Step 2. Attach the thermometer clamp to beaker.
Insert the thermometer through this clamp.

Step 5. Hook of the float

Step 3. Put the beaker on the beaker stand.
Float
Step 4. Connect the float and hook using stainless wire
whose length is approximately 50 mm.

Density pan stand
Beaker stand

Step 5. Hang the hook to density pan stand.
Step 6. Press the RE-ZERO key to display zero after weighedvalue stabilized. All preparations are complete.

6.2.

Measuring the Density of a Liquid

The density of a liquid can be obtained by the following procedure. Display example is GX-6002A.
Step 1. Hang the float into the empty beaker andpress the RE-ZERO key to display zero.
Step 2. To measure density of the liquid, pour it into the beaker.
Adjust the amount of the liquid so that the sample is approximately 10
mm under the liquid surface when the sample is hung in the liquid.
Step 3. Record absolute value A of measurement value after it becomes stable.
(As buoyancy of float A )Step 4. Acquire the density of a liquid using the following formula andsubstituting the measured value.
ρ : Calculated density of liquid [g/cm3]Aρ =+d
A : buoyancy of float [g]V
V : Volume of float (stamped on the hook) [cm3]d : Density of air (Approximately 0.001 [g/cm3])

Liquid surface
Approx. 10 mm
Step 2. Float

Example of recording sheet and calculation (3 significant figures).
Buoyancy of float A 9.970 g Volume of float V 10.01 cm3 Density of air d 1.184x10-3 g/cm3
Temperature 25 °C Atmospheric pressure 1013.25 hPa Calculated density of liquid ρ 0.997 g/cm3
9.970+ 0.001 = 0.997 [g/cm3]
10.01
11

7.

Density Measurement Using the GX-A／GF-A Balance

The GX-A / GF-A balances are equipped with a density function (specific gravity mode).
When this density determination kit GXA-13 is used with density function of the following balances,the density of a solid and liquid can be measured.
GX-203A, GX-303A, GX-403A, GX-603A, GX-1003A, GX-1603A,
GF-203A, GF-303A, GF-403A, GF-603A, GF-1003A, GF-1603A

CautionThe density function () of the balance cannot be selected when using factory settings.
The density function of the balance does not display in the function table when the specific gravity( ) of the weighing unit () is inactive. To use the specific gravity of the weighing unit, register"specific gravity" of "weighing unit" in the "function table" at first, and then select the specific gravity( ) of the weighing unit using the MODE key in weighing mode.
When the liquid density input () is active, the liquid density input () or density of solid ( ) isdisplayed. Refer to the instruction manual of balance for operation method of the "function table".
The measurement value of density (specific gravity) is fixed to 3 decimal places.

7.1.1. Preparation Before Measurement (Settings of the Function Table）
Set the function table of the balance before the density function (specific gravity mode) is used.
Enabling the Unit of Specific Gravity ()
Register the specific gravity ( ) of the weighing unit ().

Step 1. Press and hold the SAMPLE key in weighing mode.
Step 2. Press the SAMPLE key to display the weighing unitof the function table is displayed.
.

Step 3. Register the specific gravity ( ) using the following keys. (Specify order of indication.)
SAMPLE key............... Selects the weighing unit.
RE-ZERO key ............. Registers it and displays stable mark.
Step 4. When the PRINT key is pressed, the current registration is in effect.
When the CAL key is pressed, the balance returns to weighing mode.
Display the specific gravity ( ) using the MODE key.

is displayed.

Selecting Substance ( Solid or Liquid )Select a substance which is either solid or liquid. It can be specified at "substance selection( )" of "density function ()" in the function table.
Step 5. Press and hold the SAMPLE key in weighing mode.
Step 6. Select "density function (of the function table is displayed.

)" using the MODE key and enter it using the PRINT key.

Step 7. Select substance using the following keys.
SAMPLE key..........Used to select "substance selection ( )".
RE-ZERO key ........Selects either "solid density measurement ( )" or"liquid density measurement ( )".
12Description of settings is as follows:"Solid ( )" ..............Proceeds to "7.1.2. Measuring Solid Density (Specific Gravity), Function
Table" after step 9.
"Liquid ( )".............Proceeds to "7.1.4. Measuring Liquid Density (Specific Gravity),
Function Table" after step 9.
Selecting Input Method of Liquid Density Used for Solid Density Measurement (Specific Gravity)
If the density of a liquid is measured directly, proceed to step 9.
Step 8. The density of a liquid can be registered using the following keys.
SAMPLE key..........Used to select the "density function ()".
RE-ZERO key ........Specifies either "Density input of liquid using water temperature ( )" or"Direct density input of liquid ( )".
PRINT key ..............Stores the current settings.
Description of settings is as follows:"Water temperature input ( )"Proceeds from step 4of "7.1.2. Measuring Solid Density (Specific Gravity), Function Table
to "Method to Input the Water Temperature ()"
of "7.1.3. Specifying Liquid Density".
"Direct density input ( )"Proceeds from step 4of "7.1.2. Measuring Solid Density (Specific Gravity), Function Table
to "Method to Input the Density Directly ()"
of "7.1.3. Specifying Liquid Density".

""

Step 9. All preparations are complete.
To start a measurement, display the weighing mode.
Display the specific gravity ( ) using the MODE key.

Reference

The density function (specific gravity) uses "density function (Class
Density function(Specific gravity)

Item

Parameter

Liquid density input
Substance selection

Description
Density input of a liquid using water temperature
Direct density input of a liquid
Density measurement of a solid
Density measurement of a liquid

indicates factory settings.

13)" of the function table.

7.1.2. Measuring Solid Density (Specific Gravity), Function Table
Cautions

When the temperature or type of liquid changes, register again the density of the liquid using"7.1.3. Specifying Liquid Density".
The measurement value of the density function (specific gravity mode) is fixed to 3 decimal
places. The minimum division cannot be changed using the SAMPLE key.
The procedure of the density (specific gravity) measurement is to weigh the sample in air, to weighthe sample in liquid and to display calculated density of the sample.

Procedure

Step 1. Preparation of a measurement in air. (g shows,
blinks)Press the RE-ZERO key to display zero whennothing is put on the upper pan and lower pan.

From step 9 of "7.1.1. Preparation Before
Measurement (Settings of the Function Table)"

Step 2. Put the sample on the upper pan and wait until theweighing value is stable. If necessary, press the PRINT
key to output weighing value. Press the SAMPLE key
to record weighing value in air and proceed tomeasurement in liquid (g shows,
blinks).

Measurement in air
g shows,
blinksPut sample on upper pan.
Measurement in air
g shows,
blinksData is output.

Cautions

The SAMPLE key is inactive when weighing value
is negative value and overload.
Step 3. Move the sample from upper pan to lower pan. If
necessary, press the PRINT key to output weighing
value after it becomes stable. Press the SAMPLE
key to record the weighing value in liquid and proceed
to the density input of liquid (g hides,
shows).

Move sample from upper
pan to lower pan.
Measurement in liquid
g hides,shows
Data is output.

Cautions

The SAMPLE key is inactive when weighing value
is overload.
Step 4. The density input of water (g hides,
shows).
Refer to "7.1.3. Specifying Liquid Density" andinput the density of water. Press the PRINT key
to proceed to the density display of the sample.
Step 5. If necessary, while the density of the sample is displayed,press the PRINT key to output it. If another sample
is being measured, press the SAMPLE key andproceed to step 1. The unit of density (specific gravity)is .

Density of waterg hides,shows

Density (specific gravity)
g hides,shows
Data is output.
Remove sample form weighing pan

Step 6. When the temperature and type of liquid changes, if
necessary, register again the density of the liquid according
to step 4-1 of "7.1.3. Specifying Liquid Density".
Step 7. If the MODE key is pressed, the display is changed to other weighing mode.
14

7.1.3. Specifying Liquid Density
Select the density input method of a liquid when the solid density is measured.
The "liquid density input ()" has density input of liquid using water temperature ("direct density input of liquid ( )".

Method to Input the Water Temperature ()" and)Step 4-1. This step is an additional explanation of step 4 in the last page.
The current setting of water temperature is displayed. (Factory setting is 25.0 °C.)
Refer to "5.2.1. Density of Water" concerning the relation between temperature and density of water.
Register the water temperature using the following keys.
The setting range of temperature is 0.0 to 99.9 °C in 0.1 °C interval.
RE-ZERO key .................Increases number of a blinking digit. (+ key)
(Number next 9 is 0.)
MODE key......................Decreases number of a blinking digit. (- key)
(Number next 0 is 9.)
SAMPLE key...................Moves blinking digit.
PRINT key......................Stores the current setting and proceeds to the density display.
(Proceed to step 5 of last page.)
CAL key..........................Cancels the setting and proceeds to the density display.
(Proceed to step 5 of last page.)

Method to Input the Density Directly ()

Step 4-1. This step is an additional explanation of step 4 in the last page.
The current setting of density of water is displayed. (Factory setting is 1.000 g/cm3.)
Register density of water using the following keys.
The setting range of density is 0.000 to 1.999 g/cm3.
If the input becomes out of range, the balance displays
and returns to the input
display.
RE-ZERO key .................Increases number of a blinking digit. (+ key)
(Number next 9 is 0.)
MODE key......................Decreases number of a blinking digit. (- key)
(Number next 0 is 9.)
SAMPLE key...................Moves blinking digit.
PRINT key......................Stores the current setting and proceeds to the density display.
(Proceed to step 5 of last page.)
CAL key..........................Cancels the setting and proceeds to the density display.
(Proceed to step 5 of last page.)15

7.1.4. Measuring Liquid Density (Specific Gravity), Function Table
The measurement value of density (specific gravity) is fixed to 3 decimal places. Minimum division
cannot be changed using the SAMPLE key. The procedure of the density (specific gravity)
measurement is to weigh the float in air, to weigh the float in liquid and to display calculated densityof the float. Each status and indications are as follows :Procedure

Step 1. Preparation of a measurement in air. (g shows,
blinks)Press the RE-ZERO key to display zero whennothing is put on the upper pan and lower pan.
Step 2. Put the float on the upper pan and wait until the weighing
value is stable. If necessary, press the PRINT key tooutput the weighing value. Press the SAMPLE key torecord weighing value in air and proceed to themeasurement in liquid (g shows,
blinks).
To measure the density of the liquid, pour it into the beaker.
Adjust the amount of the liquid so that the float is
approximately 10 mm under the liquid surface when
float is hung in the liquid.

From step 9 of "7.1.1. Preparation Before
Measurement (Settings of the Function Table)"

Measurement in air
g shows,
blinksPut sample on upper pan.
Measurement in air
g shows,
blinksData is output.

Cautions

The SAMPLE key is inactive when weighing value
is negative value and overload.

Step 3. Put the float on lower pan and wait until the weighing
value is stable. If necessary, press the PRINT key tooutput the weighing value. Press the SAMPLE key
to record weighing value in liquid and proceed to thevolume input of the float (g hides,
shows,
shows).

Cautions

The SAMPLE key is inactive when weighing value
is negative value and overload.

Step 4. Refer to "7.1.5. Specifying Volume of Float" andinput the volume of the float. Press the PRINT key
to proceed to density indication.

Move sample from upper
pan to lower pan.
Measurement in liquid
g hides,shows
Data is output.

Volume input
g hides,shows

Density (specific gravity)
g hides,shows
Data is output.
Remove sample form weighing pan

Step 5. If necessary, while the calculated density of liquid isdisplayed, press the PRINT key to output it.
If another liquid is measured, press the SAMPLE
key and proceed to step 1.
The unit of density (specific gravity) is .
Step 6. If the MODE key is pressed, the display is changed to other weighing mode.

16

7.1.5. Specifying Volume of Float
Step 4-1. This step is an additional explanation of step 4 in the last page.
The current volume of the float is displayed. (Factory setting is 10.00 cm3.)
Register the volume using the following keys.
The setting range of volume is 0.01 to 99.99 cm3 in 0.01 cm3 interval.
RE-ZERO key .................Increases number of a blinking digit. (+ key)
(Number next 9 is 0.)
MODE key......................Decreases number of a blinking digit. (- key)
(Number next 0 is 9.)
SAMPLE key...................Moves a blinking digit.
PRINT key......................Stores the current setting and proceeds to the density display.
(Proceed to step 5 of last page.)
CAL key..........................Cancels the setting and proceeds to the density display.
(Proceed to step 5 of last page.)17

8. Frequently Asked Questions and Answers
Question:
I would like to measure the density of a resin pellet or sheet, which floats in water. Is this possible?
Answer:Use a liquid that has a lower density than water and does not dissolve the sample, such as
methanol (density 0.798) or kerosene (density 0.80). The density of the liquid used is measured
using the float provided with the kit.
Question:
Can a sample containing bubbles be measured?
Answer:
The density of a sample with bubbles contained can be measured as it is. But as time passes, thebubbles disappear and the apparent density may change. A sample, which floats on water due tothis low density, cannot be measured.
Question:
The measurement repeatability may be affected by the water's surface tension.
What can I do about this?
Answer:A few drops of a surfactant (for example, a mild detergent for washing dishes) added to the water
reduces the influence of surface tension. A few drops of a surfactant will affect the liquid density
only a very small amount. When methanol is used in place of water, the influence of surface
tension is small, even without a surfactant.
Question:
When tap water is used, bubbles are gradually generated on the sample surface and ameasurement error occurs. What can I do about this?
Answer:Tap water contains dissolved gases such as oxygen and carbon dioxide. When tap water is used,
the released dissolved gases generate bubbles. It is recommended that pure water or distilledwater, which contains few dissolved gases, be used.
Question:
I try to measure a highly water resistant material such as rubber, but bubbles stick to the sample.
What can I do about this?
Answer:
Before measurement, soak the sample in the water with an appropriate amount of surfactant
added. Doing this increases the sample surface hydrophilicity and bubbles may only stick to thesample surface in a very small amount.

18

Question:
Up to what size of sample can be measured?
Answer:Considering the density pan size, the maximum size of the sample that can be measured is asfollows: Diameter 25 mm
Height 30 mm
Question:
Can I measure the density of a liquid with a high viscosity?
Answer:A liquid with a viscosity up to 500 [mPa x s] can be measured. If the viscosity exceeds this value,
the float takes an excessive amount of time to sink and a measurement error occurs. Measuring
adhesives is not recommended because the adhesive sample may be difficult to remove from thefloat.
Question:
When a semi-micro balance is used, is accuracy improved?
Answer:Surface tension affects the measurement value in the range approximately between 0.2 mg and
1.0 mg. In a measurement using the 0.1 mg range, the magnitude of an error and the level ofbalance accuracy are almost the same. In a measurement using the 0.01 mg range, themagnitude of an error greatly exceeds the level of balance accuracy. Therefore using a semi-microbalance is not recommended.

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