DESIGN OF EXPERIMENT (DoE)
LIST OF FIGURES
FIGURE 1: MATERIALS / APPARATUS FOR THE EXPERIMENTS
LIST OF TABLES
Weighing
a measuring instrument for determining the weight or mass
Scale
of an object.
Graduated
a piece of laboratory equipment used to measure the
Cylinder
volume of a liquid.
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DESIGN OF EXPERIMENT (DoE)
Capillary Tube
Capillary tubing or capillary tubes are very thin tubes made
of a rigid material, such as plastic or glass in which a liquid
flow up into the tubes against gravity
Beaker
A deep widemouthed thin-walled vessel usually with a lip
for pouring that is used especially in science laboratories.
Table 1: DESCRIPTION OF APPARATUS THAT WILL BE USED
Height (m)
Capillary Rise (m)
Diameter (m)
Surface Tension (N/m)
0.01
0.011
0.001
0.0268
Table 2: WATER SURFACE TENSION RESULT
TRIAL
Height
Capillary Rise (m)
(m)
Diameter
Surface Tension
(m)
(N/m)
0.001
0.0701
1
5 % or 20ml
0.06
0.007
(95 % or 380ml water)
2
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DESIGN OF EXPERIMENT (DoE)
10 % or 40ml
0.06
0.004
0.001
9.761 x 10-3
0.06
0.002
0.001
4.8811 x 10-3
(90% or 360ml water)
3
5 % or 60ml
(85 % or 340ml water)
Table 3: FABRIC CONDITIONER SURFACE TENSION RESULTS
TRIAL
Height
Capillary Rise (m)
(m)
1
0.011
0.010
Diameter
Surface Tension
(m)
(N/m)
0.001
5 % or 20ml
𝟎. 𝟏𝟓𝟖𝟓 𝑵/𝒎
(2.5% or 10ml fabric conditioner,
2.5% or 10ml liquid detergent & 95
% or 380ml water)
2
0.011
0.012
0.001
10 % or 40ml
𝟎. 𝟎𝟐𝟗𝟏 𝑵/𝒎
(5% or 20ml fabric conditioner, 5%
or 20ml liquid detergent & 90% or
360ml water)
3
15 % or 60ml
0.011
0.009
0.001
𝟎. 𝟏𝟖𝟓𝟎 𝑵/𝒎
(7.5% or 30ml fabric conditioner,
7.5% or 30ml liquid detergent & 85
% or 340ml water)
Table 3 MIX: LIQUID DETERGENT & FABRIC CONDITIONER SURFACE TENSION RESULTS
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DESIGN OF EXPERIMENT (DoE)
I. GENERAL BACKGROUND
Surfactants are substances that create self-assembled molecular clusters called micelles in a
solution (water or oil phase) and adsorb to the interface between a solution and a different phase
(gases/solids). It is classified depending on its solubility, such as hydrophilic surfactants that are soluble in
water or hydrophobic (lipophilic) surfactants that are soluble in lipids. Also, surfactants are compounds that
lower the surface tension of a liquid like water, the interfacial tension between two liquids, or that between a
liquid and a solid.
The cohesive forces between molecules in a liquid are shared with all neighboring molecules. Those
on the surface have no neighboring molecules above and, thus, exhibit stronger attractive forces upon their
nearest neighbors on and below the surface. Surface tension could be defined as the property of the surface
of a liquid that allows it to resist an external force, due to the cohesive nature of the water molecules.
Reduction of surface tension of water can be done in several ways.
Detergents lower the surface tension of water. Detergent molecules have two ends, one
hydrophobic end, repelled by water and one hydrophilic end, attracted to water. In water detergent molecules
on the surface are aligned with their hydrophobic ends away from the surface. They break the surface and
thus lower the surface tension. Other detergent molecules are dispersed throughout the water. Particles of
organic matter are rendered soluble by being coated with these detergent molecules. The hydrophobic ends
stick to the particles and the hydrophilic ends point outwards.
II. EXPERIMENTAL DESIGN OBJECTIVES
This DoE aims to:
1) To describe the surface tension phenomenon
2) To describe the causes of change in surface tension of water
3) To determine the percentage of added surfactants where water’s surface tension is at its
minimum value.
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DESIGN OF EXPERIMENT (DoE)
III. EXPERIMENTAL PROGRAM
A. Framework
PROCESS
INPUT
OUTPUT
1. Get the specific gravity
Surfactants:
Liquid
Detergent and Fabric
Conditioner
of
fabric
liquid
conditioner,
detergent
Optimum Ratio
of Surfactants
and
mixed fabric conditioner
and liquid detergent by
getting
its
respective
density and dividing it to
the water’s density.
IV. PROCEDURE (Testing Standards if applicable)
For Water Only





Measuring 400ml of water using beaker
Measure the diameter of the capillary tube.
Put water to the container.
Measure the height of the water from the base of the container using the ruler.
Dip the capillary tube and measure the height of the capillary rise
For Water mixed with Surfactants






Measuring 400ml of water using beaker.
Measure the diameter of the capillary tube.
Put water to the container.
Add the surfactant into the water
Stir carefully and remove the bubbles at the surface using the sponge.
Measure the heights of the water surface and the capillary rise.
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DESIGN OF EXPERIMENT (DoE)
V. DESIGN STATISTICS
a. ANALYSIS & INTERPRETATION
The purpose of this study is to prove the effectiveness of using surfactants (Fabric Conditioner,
Detergents and Mixed of two surfactants) as reduction agent to surface tension.
Water was initially measured as well as its capillary rise in a tube beforehand. After measurement of
initial conditions, the researchers proceeded in adding surfactants to the water to be able to observe the
effect. As the experiment progresses, noticeable changes were present in the water. The water produced
bubbles as the researchers added the surfactant. Also, it became slippery. It is a normal phenomenon but it
helped the researchers predict the outcome of the experiment.
Presentation and Findings
The result and findings of this experiment are expressed in tabular form. The table will contain the
following data; three trials with different surfactant percentage, water surface height, capillary rise, capillary
tube with diameter of 1 mm. and surface tension.
I. Data Sheet of Experiment
A. Density
Liquid
Density (g/cc)
Water
0.8200
Fabric Conditioner
0.8160
Detergent
1.5170
Table. 4.1 Data for Density
As part of the experiment procedures the researchers also conducted test for density for each liquid.
Water with a density of 0.8200 g/cc, fabric conditioner with 0.8160 g/cc and detergent with a greater density
of 1.5170 g/cc. Prominently that the mass, size and particles of detergent is heavier, compacted and with
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DESIGN OF EXPERIMENT (DoE)
much matter in a certain volume of water. That leads the researchers with the possible outcome of detergent
with a least surface tension with corresponding amount of liquid detergent.
B. Surface Tension
The surface tension in the water is calculated as shown at table 4.2 with 0.0268 N/m. Since the
measuring device is least accurate, the data could also contain errors.
Height (m)
Capillary Rise (m)
Diameter (m)
Surface Tension (N/m)
0.01
0.011
0.001
0.0268
Table. 4.2 Data for Liquid Water
TRIAL
Height
Capillary Rise
Diameter
Surface Tension
(m)
(m)
(m)
(N/m)
0.06
0.007
0.001
0.0701
0.06
0.004
0.001
9.761 x 10-3
0.06
0.002
0.001
4.8811 x 10-3
1
5 % or 20ml
(95 % or 380ml water)
2
10 % or 40ml
(90% or 360ml water)
3
15 % or 60ml
(85 % or 340ml water)
Table. 4.3 Data for Liquid Fabric Conditioner
Table 4.3 shows the data for liquid fabric conditioner. Settling at 10% of liquid fabric conditioner
with least surface tension of 9.761 x 10-3, the results for liquid fabric conditioner is dramatically not
exceeding 15% of liquid fabric and not less than 5%. The ratio between the water and surfactant can affect
the data collected, although it should be at minimum. The purposes of the two surfactants are different,
therefore their functionality is also different. Detergents are designed to penetrate through the miniscule
holes in clothes while liquid fabric conditioners are only designed to smoothen surfaces without holes.
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DESIGN OF EXPERIMENT (DoE)
TRIAL
Height
Capillary Rise
Diameter
Surface Tension
(m)
(m)
(m)
(N/m)
0.011
0.06
0.001
0.2238
0.011
0.011
0.001
0.0410
0.011
0.07
0.001
0.2611
1
5 % or 20ml
(95 % or 380ml water)
2
10 % or 40ml
(90% or 360ml water)
3
15 % or 60ml
(85 % or 340ml water)
Table. 4.4 Data for Liquid Detergent
The table above shows the computations and findings for the detergent. It has reduced the surface
tension of the water up to designated percent of 10% of fabric detergent making it a reliable surfactant in
terms of reducing the surface tension. During the experiment, the researchers deduced that if the mixture
between water and the surfactant produced more bubbles, this could indicate that the surface tension of the
water is low. It is the same as boiling water; bubbles mean that the surface of the water has been disturbed.
Therefore, bubbles are important indicators of surface tension in liquid.
Moreover, there was a slight inclination to the water surface inside the capillary tube at initial
conditions. When surfactants were added, the inclination was no longer present. Instead, the water surface
inside the capillary tube was parallel with the water surface outside.
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DESIGN OF EXPERIMENT (DoE)
TRIAL
Height
Capillary Rise
Diameter
Surface Tension
(m)
(m)
(m)
(N/m)
0.011
0.010
0.001
0.1585
0.011
0.012
0.001
O.O291
1
5% or 20ml
(2.5% or 10ml fabric conditioner,
2.5% or 10ml liquid detergent &
95 % or 380ml water)
2
10% or 40ml
(10% or 20ml fabric conditioner,
5% or 20ml liquid detergent &
90% or 360ml water)
3
15% or 60ml
0.1850
(7.5% or 30ml fabric conditioner,
0.011
0.009
0.001
7.5% or 30ml liquid detergent &
85 % or 340ml water)
Table. 4.5 Data for Mixed Liquid Fabric Conditioner and Liquid Detergent
See table 4.5 above to for the results of mixed liquid fabric conditioner and liquid detergent. A
percentage of 20% of mixed surfactants, 10% of liquid fabric conditioner and 10% of liquid detergent that
reduced the surface tension of the water as shown in table 4.3 and table 4.4 which is more reliable as a
surfactant in terms of its surface tensions. While performing the laboratory, the researchers noticed that there
is an inevitable reaction between the fabric conditioner and the detergent that form small solids in the fluids.
In the other hand, it causes the result of the surface tension greatly with between liquid fabric conditioner
alone and liquid detergent alone.
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DESIGN OF EXPERIMENT (DoE)
VI. CONCLUSION AND GENERAL RECOMMENDATIONS
Conclusion
We therefore conclude that the surfactant reduces the surface tension of the liquid it is added to. Reducing
surface tension increase the vapor pressure because it makes it easier for molecules to overcome the surface
tension and break free. And capillarity is the result of cohesion of water molecules and adhesion of those
molecules to a solid material. In the case of a glass tube inserted in water with openings at both ends, as the
edges of the tube are brought closer together, such as in a very narrow tube, the liquid will be drawn upward
in the tube. The more narrow the tube, the greater the rise of the liquid. Greater surface tension and increased
ratio of adhesion to cohesion also result in greater rise.
Also the adhesion of water to the surface of a material will cause an upward force on the liquid. The surface
tension acts to hold the surface intact. Capillary action happens when the adhesion to the surface material is
stronger than the cohesive forces between the water molecules. Due to the added surfactants the adhesion
and cohesion of water, surface tension and the capillary rise was affected.
Recommendation
The following are recommendations with reference to aforementioned limitations:

The important findings in this study are not generalized to limited brand of added surfactants
into water sample at a room temperature. Further research can be conducted in several percentage
by volume of multiple trials.

Future design experiment must considered necessary improvement to developed
enhancement for lack of materials and equipment to acquire accurate measurements in achieving
more reliable data and results.

Other factors that influenced the surface tension of water must be examined to trial testing.
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DESIGN OF EXPERIMENT (DoE)
VII. REFERENCES
Rinchon, J. P. M., Concha, N. C., & Calilung, M. G. V. (2017). Reinforced concrete ultimate bond strength
model using hybrid neural network-genetic algorithm. Paper presented at the Humanoid,
Nanotechnology, Information Technology, Communication and Control, Environment and
Management (HNICEM), 2017 IEEE 9th International Conference on.
INTRODUCTION
•
https://www.sciencedirect.com/topics/chemistry/surfactant
•
https://water.usgs.gov/edu/surface-tension.html
•
http://labman.phys.utk.edu/phys221core/modules/m7/surface_tension.html
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