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  <front>
    <journal-meta>
      <journal-id journal-id-type="publisher-id">ijese</journal-id>
      <journal-title-group>
        <journal-title>Interdisciplinary Journal of Environmental and Science
Education</journal-title>
      </journal-title-group>
      <issn publication-format="electronic">2633-6537</issn>
      <publisher>
        <publisher-name>Modestum</publisher-name>
      </publisher>
    </journal-meta>
    <article-meta>
      <article-id pub-id-type="doi">10.29333/ijese/18526</article-id>
      <title-group>
        <article-title>Physicochemical analysis of commercial detergents using
standard and alternative instruments: Approaches to teaching exact
sciences</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author" corresp="yes">
          <contrib-id contrib-id-type="orcid">0000-0003-0326-5795</contrib-id>
          <name>
            <surname>dos Santos Niculau</surname>
            <given-names>Edenilson</given-names>
          </name>
          <email>edenilson.niculau@ufnt.edu.br</email>
          <xref ref-type="aff" rid="aff-1" />
          <xref ref-type="corresp" rid="cor-true">
            <sup>*</sup>
          </xref>
        </contrib>
        <contrib contrib-type="author">
          <contrib-id contrib-id-type="orcid">0000-0003-3386-2769</contrib-id>
          <name>
            <surname>Lima Carvalho</surname>
            <given-names>Leandro</given-names>
          </name>
          <xref ref-type="aff" rid="aff-2" />
        </contrib>
        <contrib contrib-type="author">
          <contrib-id contrib-id-type="orcid">0000-0003-3117-8330</contrib-id>
          <name>
            <surname>dos Anjos Alves</surname>
            <given-names>Melquisedeque</given-names>
          </name>
          <xref ref-type="aff" rid="aff-3" />
        </contrib>
        <contrib contrib-type="author">
          <contrib-id contrib-id-type="orcid">0009-0009-1503-8021</contrib-id>
          <name>
            <surname>Ribeiro Tavares</surname>
            <given-names>Pedro Lucas</given-names>
          </name>
          <xref ref-type="aff" rid="aff-2" />
        </contrib>
        <contrib contrib-type="author">
          <contrib-id contrib-id-type="orcid">0009-0001-4970-2041</contrib-id>
          <name>
            <surname>de Assis Araújo Alencar</surname>
            <given-names>Gabriel</given-names>
          </name>
          <xref ref-type="aff" rid="aff-2" />
        </contrib>
        <contrib contrib-type="author">
          <contrib-id contrib-id-type="orcid">0009-0003-1158-5593</contrib-id>
          <name>
            <surname>Mendes Figueiredo</surname>
            <given-names>Rogerio</given-names>
          </name>
          <xref ref-type="aff" rid="aff-2" />
        </contrib>
        <contrib contrib-type="author">
          <contrib-id contrib-id-type="orcid">0009-0001-6195-1104</contrib-id>
          <name>
            <surname>Pereira de Oliveira</surname>
            <given-names>José Henrick</given-names>
          </name>
          <xref ref-type="aff" rid="aff-2" />
        </contrib>
        <contrib contrib-type="author">
          <contrib-id contrib-id-type="orcid">0000-0003-0962-4453</contrib-id>
          <name>
            <surname>Gomes da Silva</surname>
            <given-names>Karen Leticia</given-names>
          </name>
          <xref ref-type="aff" rid="aff-1" />
        </contrib>
        <aff id="aff-1">
          <label>1</label>
          <institution-wrap>
            <institution>Centro de Ciências Integradas, Universidade Federal do
Norte do Tocantins, Araguaína, TO, BRAZIL</institution>
          </institution-wrap>
        </aff>
        <aff id="aff-2">
          <label>2</label>
          <institution-wrap>
            <institution>Colégio Estadual Adá de Assis Teixeira, Secretaria de
Estado da Educação do Tocantins, Palmas, TO, BRAZIL</institution>
          </institution-wrap>
        </aff>
        <aff id="aff-3">
          <label>3</label>
          <institution-wrap>
            <institution>Universidade Federal do Tocantins, Palmas, TO,
BRAZIL</institution>
          </institution-wrap>
        </aff>
      </contrib-group>
      <pub-date date-type="pub" publication-format="electronic" iso-8601-date="2026-05-05">
        <day>5</day>
        <month>5</month>
        <year>2026</year>
      </pub-date>
      <volume>22</volume>
      <issue>2</issue>
      <elocation-id>e2614</elocation-id>
      <permissions>
        <copyright-statement>Copyright © 2026 by Author/s and Licensed by
Modestum DOO, Serbia.</copyright-statement>
        <copyright-year>2026</copyright-year>
        <license license-type="open-access" xlink:href="http://creativecommons.org/licenses/by/4.0/">
          <license-p>This is an open access article distributed under the Creative
Commons Attribution License which permits unrestricted use,
distribution, and reproduction in any medium, provided the original work
is properly cited.</license-p>
        </license>
      </permissions>
      <abstract>
        <p>
The development of low-cost alternative laboratory tools has become
increasingly important for interdisciplinary teaching in physics,
chemistry, and mathematics. In this study, high school students applied
project-based learning and investigation teaching sequences
methodologies to design and build an alternative viscometer for
educational use. This device was employed to measure the flow times and
estimate the viscosities of ten commercial detergent brands, classified
as Newtonian and quasi-Newtonian fluids. Results showed that the
alternative viscometer produced consistent viscosity and density
measurements, demonstrating its potential as a practical, low-cost
instrument to enhance science and mathematics education.
</p>
      </abstract>
      <kwd-group kwd-group-type="author">
        <kwd>viscometers</kwd>
        <kwd>physical and chemical properties</kwd>
        <kwd>project-based learning educational methodologies</kwd>
        <kwd>investigation teaching sequence</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="introduction">
      <title>INTRODUCTION</title>
      <p>The construction of alternative equipment and instruments using
  recyclable and reusable low-cost materials emerges as a promising and
  environmentally sustainable solution (Chen &amp; Breeding, 2022;
  Gonçalves &amp; Goi, 2020; Harrison et al., 2025; Idul et al., 2025),
  capable of contributing both to reducing environmentally polluting
  waste (Bhanderi et al., 2023; Enayati et al., 2023; Massoud &amp;
  Dsilva, 2025; Muringayil et al., 2024) and substantially improving the
  teaching and learning of curricular components in the Natural
  Sciences, Mathematics, and its Technologies area.</p>
      <p>According to Monegro et al. (2024), it is estimated that by 2050,
  plastic accumulation in landfills and water bodies will reach an
  astonishing 12,000 mt, with only 9% being recycled and the remainder
  incinerated or deposited in landfills.</p>
      <p>Zhao et al. (2024) highlights that waste rubber is another
  pollutant of great concern, commonly referred to as black pollution
  Approximately 1.5 billion used tires are generated annually worldwide,
  with China contributing around 20 million tons of used tires each
  year, growing at an annual rate of 6-8% (Hashamfirooz et al., 2025;
  Jiang et al., 2023; Machin et al., 2017; Zaki et al., 2025).</p>
      <p>Therefore, proposals and resources presented in the literature that
  address interdisciplinary teaching in physics, chemistry, and
  mathematics, particularly involving the construction of equipment and
  instruments made from recyclable and reusable materials (such as
  rubber, paper, plastic, glass, etc.), are essential today to reduce
  the disposal of environmentally harmful products (Fritz et al., 2025;
  Gonçalves &amp; Goi, 2020; Panda et al., 2020; Snovarski Fonseca et
  al., 2018).</p>
      <p>To promote and support interdisciplinary teaching and learning in
  physics, chemistry, and mathematics at the high school level (Borji
  &amp; Martínez-Planell, 2023; Gruver &amp; Hawthorne, 2023; Niemann et
  al., 2024; Setlik &amp; Silva, 2023; Stroumpouli &amp; Tsaparlis,
  2022), this study introduces an Alternative Viscometer constructed
  from low-cost, recyclable, and reusable materials. The device is
  designed to experimentally determine physicochemical properties such
  as density and viscosity of surfactant-based detergents widely
  marketed as household cleaning products in Brazil (Hajikarimi &amp;
  Moghadas, 2021a, 2021b; Malkin &amp; Isayev, 2012).</p>
      <p>Andraca et al. (2013) for instance, studied the
  temperature-dependent viscosity of honey and observed a linear
  relationship based on the WLF equation. This shows that it is possible
  to adapt and present alternative interdisciplinary approaches to
  teaching Physics, Chemistry, and Mathematics (Andraca et al., 2013;
  Lähde et al., 2022).</p>
      <p>Viscous materials such as lubricating oils can also serve as a
  viable alternative for studying viscosity in the context of
  diversified classes. Sodré et al. (2011) presented a study relating to
  increased oil viscosity with reduced production of unburned
  hydrocarbons.</p>
      <p>The topic of viscosity can be explored in various teaching contexts
  at the high school level. In a study by Patel et al. (2022) the
  authors addressed rheology, an interdisciplinary field involving
  physics, chemistry, biology, and mathematics. They studied the steady
  and dynamic shear of Indian jujube (<italic>ziziphus
  mauritiana</italic> lam.) pulp and were able to determine several
  physicochemical, textural, and thermal properties of the fruit.</p>
      <p>A wide range of commercial products, familiar to students, can be
  incorporated into diversified classes as tools for teaching and
  learning. One example is determining the viscosity of ethanol-based
  hand sanitizing gels (Xie et al., 2023), a widely used pharmaceutical
  product in recent years as a preventive measure during the COVID-19
  pandemic peak in 2020 (Berardi et al., 2020; Oliveira D’Alessandro et
  al., 2023).</p>
      <p>In this work, the main objective was to present an alternative
  methodology for building a low-cost viscometer instrument for
  experimental activities in diversified classes of physics, chemistry,
  and mathematics. The instrument was specifically developed to be
  applied in measuring the viscosities of sanitizing detergents widely
  commercialized in Brazil (Hashmi et al., 2022; Liu et al., 2022;
  Meffan et al., 2023).</p>
    </sec>
    <sec id="interdisciplinary-educational-methodologies">
      <title>INTERDISCIPLINARY EDUCATIONAL METHODOLOGIES</title>
      <p>In the context of chemistry education, there is a growing need to
  implement innovative methodological strategies that promote more
  effective teaching and learning processes. Considering the limitations
  currently faced, several problems are associated with students’
  difficulties in understanding abstract chemical concepts, which may be
  linked to the lack of contextualization and the absence of
  experimental activities, the latter being described as crucial tools
  for promoting more meaningful learning (Asaki &amp; Adu-Gyamfi, 2025;
  Almahdawi et al., 2025).</p>
      <p>There are many established methodologies in the expert literature
  directed uniquely for teaching and learning which are poorly explored
  for both elementary and high school levels. In this work, the
  combination of educational principles found in the
  “<italic>Metodologias de ensino por aprendizagem baseada em
  projetos</italic> (ABP) <italic>e sequência de ensino por
  investigação</italic> (SEI) [Project-based learning teaching
  methodologies and investigation learning sequence]” was prioritized
  (Astawa et al., 2017; Bell, 2010; Pérez-Sánchez et al., 2018; Zhang
  &amp; Ma, 2023).</p>
      <p>Through the project-based learning and the investigation learning
  sequence, teaching models consisting of inciting reflections on issues
  or necessities perceived in the daily lives of students, were adopted
  as notable methodologies so that, within an universe of perceptions
  and observations of products sold and consumed daily, the would
  propose alternative models of creative experimental projects to verify
  and/or determine physical and chemical properties of marketed products
  associated with the interdisciplinary themes applied in the class
  setting, thus employing mathematical statistical principles and
  groundwork through the use of software, such as Excel, GeoGebra, Apple
  Numbers, Quip, EtherCalc, etc., with ample access facilitated by
  different kinds of electronic devices and equipment. In this work, the
  adopted methodologies were systematically aligned with criteria based
  on the learning objectives and goals established in the document
  “<italic>base nacional comum curricular</italic> [national common
  basic curriculum]” (Ministério da Educação, 2018).</p>
      <p>Thus, in order to include the interdisciplinarity between different
  curriculum components, the students worked with theme “Newtonian or
  quasi-Newtonian fluids”, as this subject encompasses the possibility
  of interlinking concepts involving different “high school” curricular
  disciplines, such as physics, chemistry, and mathematics, in
  “classroom and interdisciplinary experimental laboratory practices”
  settings.</p>
    </sec>
    <sec id="materials-and-methods">
      <title>MATERIALS AND METHODS</title>
      <sec id="mass-and-density-measurement-of-commercial-detergents">
        <title>Mass and Density Measurement of Commercial Detergents</title>
        <p>Three samples of commercial materials in graduated cylinders
    containing fixed volumes of 100 mL were analyzed for indirect
    measurements of commercial detergents density. Furthermore, the
    analysis of samples of different commercial products followed an
    experimental procedure of triplicate measurements rigorously. This
    is a recommended model for educational laboratories because it is an
    acceptable compromise between accuracy and work (Firmani et al.,
    2020). Thus, the following equipment and instruments used in the
    triplicate analysis are described in <bold><xref ref-type="table" rid="table-376">Table 1</xref></bold>.</p>
        <p>The chart in <bold><xref ref-type="fig" rid="figure-5085">Figure 1</xref></bold> presents the steps for the
    measurement of “masses (m) and densities (d) of commercial products”
    taken as examples of Newtonian or quasi-Newtonian fluids (Eq. [1]
    and Eq. [2]).</p>
        <p>Initially, direct measurements of the integral mass of 10
    different brands of commercial detergents were performed on a B-Max®
    digital electronic scale sold in the “state of tocantins”.
    Afterwards, the mass of graduated glass cylinders with maximum
    volume graduation of 100 mL was measured using the same electronic
    scale. The weighing procedure of measurement recipients containing
    100 mL volumetric samples of commercial detergents was repeated in
    triplicate and, after subtracting the particular mass of each
    graduated cylinder from the total composition of masses (Eq. [1]),
    only the amounts for the mass of Newtonian or quasi-Newtonian fluids
    were obtained. When relating the mass of fluids with the volumes of
    graduated cylinders, the amounts of “commercial product density”
    were obtained indirectly (Eq. [2]).</p>
        <table-wrap>
          <table style="width:100%">
            <colgroup>
              <col width="33%" />
              <col width="33%" />
              <col width="33%" />
            </colgroup>
            <thead>
              <tr>
                <th> </th>
                <th>
                  <p>
                    <named-content content-type="math">\[m_{(commercial\
            detergent\ sample)}\]</named-content>
                  </p>
                  <p>
                    <named-content content-type="math">\[= m_{(graduated\
            cylinder + detergent)}{- m}_{\lbrack graduated\ cylinder(v =
            100ml)\rbrack}\]</named-content>
                  </p>
                </th>
                <th align="right">(1)</th>
              </tr>
            </thead>
            <tbody>
            </tbody>
          </table>
        </table-wrap>
        <table-wrap>
          <table style="width:100%">
            <thead>
              <tr>
                <th> </th>
                <th>
                  <named-content content-type="math">\[d_{detergent}^{T =
            22 \rightarrow 28ºC} = \frac{{Mass}_{(commercial\ detergent\
            sample)}}{{Volume}_{(graduated\ cylinder\ with\ fixed\ 100\
            mL\ of\ commercial\ detergent)}} =
            \frac{m}{v}\]</named-content>
                </th>
                <th align="right">(2)</th>
              </tr>
            </thead>
            <tbody>
            </tbody>
          </table>
        </table-wrap>
      </sec>
      <sec id="production-of-an-alternative-viscometer-based-on-low-cost-materials">
        <title>Production of an Alternative Viscometer Based on Low-Cost
    Materials</title>
        <p>The alternative, low commercial cost materials used in the
    production of the viscometer prototype to measure “Newtonian or
    quasi-Newtonian fluids” are presented in (<bold><xref ref-type="table" rid="table-377">Table 2</xref></bold>).</p>
        <p>The production of an “alternative viscometer” with alternative,
    low-cost materials as a proposal of experimental laboratory
    instrument resource for interdisciplinary teaching and learning in
    “diversified laboratory classes of physics, chemistry, and
    mathematics” was produced as presented in the ordered steps of the
    illustrated flowchart in <bold><xref ref-type="fig" rid="figure-5086">Figure 2</xref></bold>.</p>
      </sec>
      <sec id="viscosity-measurement-of-newtonian-or-quasi-newtonian-fluids-with-standard-and-alternative-viscometers">
        <title>Viscosity Measurement of Newtonian or quasi-Newtonian Fluids
    with Standard and Alternative Viscometers</title>
        <p>Ford cup no. 4, manufactured by “Nalgon Equipamentos Científicos
    LTDA”, is produced with polypropylene, stainless steel, anodized
    aluminum, brass metallic orifice and is corrosion resistant. This
    viscometer was standardized as per “NBR rules–5849, MB–1117 and ASTM
    D–1200. It is distinctly used for analyses involving only Newtonian
    or quasi-Newtonian fluids.</p>
        <p>However, the evaluation of thixotropic products (non-Newtonian)
    must be intrinsically avoided. Prior to any viscometry assessment
    with “Ford cups”, perform tests in a windless area, without rapid
    changes in temperature, and, for greater precision, the local
    temperature must be between 22 and 28 ºC. The safe viscosity range
    for flow assessments with “Ford cup no. 4 (∅<sub>orifice
    diameter</sub> = 4.12 mm)” is between 40 and 370 CsT (mm<sup>2</sup>
    s<sup>-1</sup>). Basically, a chronometer and a standing thermometer
    must be used in the viscometrical analysis when using the viscometer
    no. 4 for “Newtonian or quasi-Newtonian fluids” (<bold><xref ref-type="table" rid="table-376">Table 1</xref></bold>).</p>
        <p>Triplicate measured times characteristic of Newtonian and
    non-Newtonian fluids must be obtained at the “first visual shearing
    of commercial products” during the flow process both for the
    “standard viscometer” and the “alternative viscometer” (<bold><xref ref-type="fig" rid="figure-5087">Figure 3</xref></bold>).</p>
        <p>Subsequently, in order to obtain the estimated values for
    viscosity of the 10 brands of “detergents sold in the state of
    tocantins”, a “time-dependent (𝑣) viscosity function (𝑡)” already
    presented by “Nalgon Equipamentos Científicos LTDA” for the “Ford
    cup no. 4”, as below: 𝑣(𝑡) = 3.85𝑡 − 17.2865 (Eq. [3]).</p>
        <p>Where the angular coefficient of the line is 3.85 and the linear
    correlation coefficient (r) is equal to 0.99, obtained through a
    thorough conditional statistical procedure study of variables
    involving “linear regression”, characteristically disposed at the
    Cartesian time coordinate, and the linear coefficient of the line
    with a value equal to -17.2865, obtained around the point limits (𝑡
    → 0), statistically located and estimated at the viscosity value
    coordinates 𝑣(𝑡). Nalgon Equipamentos Científicos LTDA has a
    statistical control data archive regarding the precision and
    exactness of the “Ford cup no. 4” with assured maximum experimental
    statistical deviation of 1% at the conditions and temperature range
    of 22 to 28 ºC.</p>
      </sec>
    </sec>
    <sec id="results-and-discussion">
      <title>RESULTS AND DISCUSSION</title>
      <p>Students produced (<bold><xref ref-type="table" rid="table-378">Table 3</xref></bold>), which contains
  statistical data related to the triplicate measurement of the mass of
  commercial detergents, obtained from employing data treatment with the
  software Excel. They were encouraged to work with Excel tabs that
  already contain proposals for building and treating “statistical
  calculations” (Silva de Souza &amp; Borges, 2023). Thus, the
  statistical values of means (µ<sub>g</sub>), variances
  (Δσ<sub>g</sub>), standard deviations (σ<sub>g</sub>) and coefficients
  of variation as percentages (CV%) were observed as individual
  statistical parameters for each “commercial product” as examples of
  Newtonian and/or quasi-Newtonian fluids and presented coherent
  statistical values between the analyzed parameters. Information on the
  statistical parameters that establish the comparison between the whole
  mass of “commercial detergents” as statistical values of mean
  (µ<sub>Products[g]</sub>), variance (S<sup>2</sup><sub>g</sub>),
  standard deviation (s<sub>g</sub>), and coefficient of variation as
  percentage (CV%) is presented in <bold><xref ref-type="table" rid="table-378">Table 3</xref></bold>. In terms of
  analyzed statistical parameters, s<sub>(g)</sub> = 7.57 and CV = 1.45%
  are highlighted. The CV indicator observed in <bold><xref ref-type="table" rid="table-378">Table 3</xref></bold>, in
  probability and statistics theory, is considered a low value for the
  presented data set, consequently meaning that there is a quality
  control during the industrial production of commercial detergents of
  different brands in Brazil.</p>
      <p>Proceeding with experimental studies and statistical treatments for
  “commercial products”, classified as Newtonian and/or quasi-Newtonian
  fluids, as they are presented in <bold><xref ref-type="table" rid="table-379">Table 4</xref></bold>. Students
  estimated the mean values of relative density for samples of
  “commercial detergents” in triplicate. Thus, the mean mass of samples
  was employed as presented in <bold><xref ref-type="table" rid="table-378">Table 3</xref></bold>. Densities estimated
  from statistical analysis presented a mean of 0.99 g mL<sup>-1</sup>
  with a standard deviation of 0.0136 g mL<sup>-1</sup> and a
  coefficient of variation of 1.37%. Students were able to compare
  estimated statistical standards for density analysis between the
  different “commercial products” studied and, overall, were able to
  show through the observed data that statistical parameters showed
  dispersion values deemed low and insignificant; thus, the commercial
  detergents are standardized and follow certain manufacturing quality
  control parameters.</p>
      <p>Concerning <bold><xref ref-type="table" rid="table-380">Table 5</xref></bold> and <bold><xref ref-type="table" rid="table-381">Table 6</xref></bold>, the
  viscosities estimated from statistical parameters based on flow time
  obtained by “standard viscosimeter Ford no. 4 and alternative” are
  presented. In <bold><xref ref-type="table" rid="table-380">Table 5</xref></bold>, note the values of flow time
  measured for the determination of viscosities (Ѵ<sub>1</sub>
  [mm<sup>2</sup> s<sup>-1</sup>]) of commercial detergents. When
  observing all brands of commercial products, detergent A showed the
  greatest estimated mean value of 399.82 mm<sup>2</sup> s<sup>-1</sup>;
  followed by detergent F 295.33 mm<sup>2</sup> s<sup>-1</sup>;
  detergent C 291.71 mm<sup>2</sup> s<sup>-1</sup>, detergent H 245.21
  mm<sup>2</sup> s<sup>-1</sup>, detergent B 217.60 mm<sup>2</sup>
  s<sup>-1</sup>, detergent D 211.21 mm<sup>2</sup> s<sup>-1</sup>,
  detergent I 191.00 mm<sup>2</sup> s<sup>-1</sup>, detergent G 179.99
  mm<sup>2</sup> s<sup>-1</sup>, detergent E 168.17 mm<sup>2</sup>
  s<sup>-1</sup> e detergent J 159.58 mm<sup>2</sup> s<sup>-1</sup>,
  respectively, in decreasing order of estimated viscosity values. Seek
  proposals for the required explanations regarding the decreasing
  sequence of estimated viscosity values, students performed a thorough
  investigation on possible causes for the obtained data. Among the
  several proposals discussed, they arrived at the consensus that the
  chemical ingredients employed were handled with small percentage
  variations of its respective masses (m/m%).</p>
      <p>When comparing the values presented in <bold><xref ref-type="table" rid="table-380">Table 5</xref></bold> and
  <bold><xref ref-type="table" rid="table-381">Table 6</xref></bold>, it is possible to observe that estimated
  viscosity values are distinct and show significant differences
  regarding those estimated in <bold><xref ref-type="table" rid="table-381">Table 6</xref></bold>, obtained through
  the “alternative viscometer (<bold><xref ref-type="fig" rid="figure-5087">Figure 3</xref></bold>)”. Therefore, it is
  also verified that, as observed in the data analysis of <bold><xref ref-type="table" rid="table-380">Table 5</xref></bold>, mean viscosities estimated for the different “detergent
  brands” follow a decreasing order of values: detergent A 356.66
  mm<sup>2</sup> s<sup>-1</sup>, detergent F 253.87 mm<sup>2</sup>
  s<sup>-1</sup>, detergent C 184.76 mm<sup>2</sup> s<sup>-1</sup>,
  detergent B 162.28 mm<sup>2</sup> s<sup>-1</sup>, detergent D 127.36
  mm<sup>2</sup> s<sup>-1</sup>, detergent E 95.13 mm<sup>2</sup>
  s<sup>-1</sup>, detergent H 91.78 mm<sup>2</sup> s<sup>-1</sup>,
  detergent G 65.10 mm<sup>2</sup> s<sup>-1</sup>, detergent I 54.96
  mm<sup>2</sup> s<sup>-1</sup> and detergent J 14.94 mm<sup>2</sup>
  s<sup>-1</sup>, respectively, measured through the “alternative
  viscometer”. As the proposed measurement instrument was produced based
  on the “standard viscometer no. 4”, students hypothesized that the
  estimated mean viscosities values (Ѵ<sub>2</sub> [mm<sup>2</sup>
  s<sup>-1</sup>]) would also follow a decreasing order of values for
  the commercial detergents analyzed.</p>
      <p>After meticulously analyzing <bold><xref ref-type="table" rid="table-380">Table 5</xref></bold> and <bold><xref ref-type="table" rid="table-381">Table 6</xref></bold>, students plotted a chart using Excel tools, as shown in
  <bold><xref ref-type="fig" rid="figure-5088">Figure 4</xref></bold>, one for mean viscosities obtained with the
  “standard viscometer instrument Ford no. 4 (Ѵ<sub>1</sub>
  [mm<sup>2</sup> s<sup>-1</sup>])” and another with the “alternative
  viscometer instrument (Ѵ<sub>2</sub> [mm<sup>2</sup>
  s<sup>-1</sup>])”, which was proposed as an alternative for
  experimental studies with “Newtonian and/or quasi-Newtonian
  fluids.</p>
      <p>The results of this study highlight the importance of implementing
  low-cost experimental approaches in chemistry education, contributing
  to the understanding of abstract concepts and promoting student
  engagement. In this context, the use of recyclable materials supports
  discussions related to environmental issues by encouraging sustainable
  practices and the responsible use of resources. These aspects
  reinforce the relevance of interdisciplinary approaches in science
  education. Therefore, for future studies, it is recommended to analyze
  the application of these methodologies in different educational
  contexts, as well as their long-term impact on the teaching and
  learning process and on environmental awareness.</p>
    </sec>
    <sec id="conclusion">
      <title>CONCLUSION</title>
      <p>The importance of developing alternative, low-cost instruments and
  equipment for experimentally diversified classes of sciences,
  mathematics, and its technologies has allowed students to better
  understand themes deemed complex that are presented in the fields of
  physics, chemistry, and math. The general objective proposed in this
  work was to determine the physical and chemical properties of 10
  different brands of anionic surfactants, such as mass, volume,
  density, and viscosity, through alternative instruments and equipment
  produced with recyclable and reusable materials. In addition, through
  the principles and groundwork set in the “Project-based learning (ABP)
  teaching methodologies and investigation teaching sequence (SEI)”,
  students exchanged many kinds of knowledge in a dynamic relationship
  among their peers and set on to produce a viscometer with alternative
  materials capable of accurately and safely measuring flow times of
  “Newtonian and/or quasi-Newtonian fluids” of anionic surfactant
  products sold in Brazil, also called “Detergents”, by proposing
  resources for diversified classes that facilitate the understanding
  and learning of themes deemed complex associated with the teaching of
  sciences, mathematics, and its technologies.</p>
      <p>Thus, through the alternative instrument produced by the students,
  they were able to determine the measured viscosities and successfully
  outline them statistically for different triplicate samples of
  “detergents” sold in Brazil. In light of the foregoing, it is also
  possible to produce new, alternative viscometers with recyclable and
  reusable materials based on capillary, falling-piston, rotational,
  vibrational viscometers, etc., which can be applied in other types of
  samples and physical and/or chemical systems. In summary, projects
  developed with alternative materials are becoming more necessary, both
  to improve teaching and learning and to promote more accessible,
  low-cost, diversified educational resources to the “teaching of
  sciences, mathematics, and its technologies”.</p>
      <p>
        <bold>Author contributions:</bold>
        <bold>ESN:</bold>
  conceptualization, formal analysis, investigation, methodology,
  project administration, software, supervision, validation,
  visualization, and writing–review &amp; editing; <bold>LLC:</bold>
  conceptualization, data curation, formal analysis, investigation,
  methodology, project administration, software, supervision,
  validation, visualization, writing–original draft, and writing–review
  &amp; editing; <bold>MAA:</bold> conceptualization, formal analysis,
  investigation, methodology, software, validation, visualization, and
  writing–original draft; <bold>PLRT:</bold> conceptualization, formal
  analysis, methodology, software, validation, and visualization;
  <bold>GAAA:</bold> conceptualization, formal analysis, methodology,
  software, validation, and visualization; <bold>RMF &amp; JHPO:</bold>
  conceptualization, formal analysis, methodology, software, validation,
  and visualization; &amp; <bold>KLGS:</bold> conceptualization, data
  curation, formal analysis, investigation, methodology, software,
  supervision, validation, visualization, writing–original draft, and
  writing–review &amp; editing. All authors agreed with the results and
  conclusions.</p>
      <p>
        <bold>Funding:</bold> This study was supported by the Adá de Assis
  Teixeira State School, the Coordination for the Improvement of Higher
  Education Personnel, and the National Institute of Science and
  Technology for Food.</p>
      <p>
        <bold>Ethical statement:</bold> The authors stated that the study
  did not involve human participants, animals, or any procedures
  requiring approval by an ethics committee; therefore, ethical approval
  was not required.</p>
      <p>
        <bold>AI statement:</bold> The authors stated that no AI tools were
  used.</p>
      <p>
        <bold>Declaration of interest:</bold> No conflict of interest is
  declared by the authors.</p>
      <p>
        <bold>Data sharing statement:</bold> Data supporting the findings
  and conclusions are available upon request from the corresponding
  author.</p>
    </sec>
  </body>
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    <sec sec-type="display-objects">
      <title>Figures and Tables</title>
      <fig id="figure-5085">
        <label>Figure 1</label>
        <caption>
          <p>Flowchart with simplified experimental scheme to measure mass,
volume, and density of different detergent products (Source: Authors’
own elaboration)</p>
</caption>
        <graphic xlink:href="https://www.ijese.com/figures/5085/figure1.png" />
      </fig>
      <fig id="figure-5086">
        <label>Figure 2</label>
        <caption>
          <p>Manufacturing scheme of alternative viscometers with recyclable or
reusable materials applied to the study of Newtonian or quasi-Newtonian
fluids (Source: Authors’ own elaboration)</p>
</caption>
        <graphic xlink:href="https://www.ijese.com/figures/5086/figure2.png" />
      </fig>
      <fig id="figure-5087">
        <label>Figure 3</label>
        <caption>
          <p>Viscometer set for measuring viscosity of anionic surfactants
(Source: Authors’ own elaboration)</p>
</caption>
        <graphic xlink:href="https://www.ijese.com/figures/5087/figure3.png" />
      </fig>
      <fig id="figure-5088">
        <label>Figure 4</label>
        <caption>
          <p>Viscosities obtained through the standard viscometer Ford no. 4 and
alternative viscometer (Source: Authors’ own elaboration)</p>
</caption>
        <graphic xlink:href="https://www.ijese.com/figures/5088/figure4.png" />
      </fig>
      <table-wrap id="table-376">
        <label>Table 1</label>
        <caption>Equipment employed for measuring mass and density of commercial detergents</caption>
        <table>
          <tbody>
            <tr>
              <td>
                <p>
                  <bold>Instruments</bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>Brand®/model</bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>Specifications</bold>
                </p>
              </td>
            </tr>
            <tr>
              <td>
                <p>Electronic scale</p>
              </td>
              <td>
                <p>B-Max®/SF-400</p>
              </td>
              <td>
                <p>10,000 g ± 1 g capacity</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>Graduated glass beakers</p>
              </td>
              <td>
                <p>Qualividros boro 3.3</p>
              </td>
              <td>
                <p>250 mL capacity with 50 mL graduations</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>Graduated glass cylinder</p>
              </td>
              <td>
                <p>Global boro 3.3</p>
              </td>
              <td>
                <p>100 mL ± 1 mL capacity</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>Chemical thermometer w/external scale, red
        liquid</p>
              </td>
              <td>
                <p>Incoterm/ref. 5041</p>
              </td>
              <td>
                <p>T<sub>min</sub> = -10 ºC, T<sub>max</sub> = 110 ºC,
        deviation= ± 1 ºC, height = 260 mm, and diameter = 6 mm</p>
              </td>
            </tr>
          </tbody>
        </table>
      </table-wrap>
      <table-wrap id="table-377">
        <label>Table 2</label>
        <caption>Low commercial cost materials used in the production of the viscometer prototype</caption>
        <table>
          <tbody>
            <tr>
              <td>
                <p>
                  <bold>Instruments</bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>Brand®/model</bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>Specifications</bold>
                </p>
              </td>
            </tr>
            <tr>
              <td>
                <p>General-use electrical tape</p>
              </td>
              <td>
                <p>TEKBOND</p>
              </td>
              <td>
                <p>19 mm × 10 m × 0.13 mm</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>Nail</p>
              </td>
              <td>
                <p>Gerdau</p>
              </td>
              <td>
                <p>Dimensions (JP × LPP): 17 × 21 mm</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>PET bottle</p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p>2L capacity</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>30 cm aluminum ruler</p>
              </td>
              <td>
                <p>EDA/5UC</p>
              </td>
              <td>
                <p>Height = 30 cm; level containing 3 12’’ bubbles</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>Professional rubbered craft knife</p>
              </td>
              <td>
                <p>MFL/TRAVA</p>
              </td>
              <td>
                <p>Blade = 18 mm; height = 4 cm; length = 16.5 cm</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>Long, straight-nose plier</p>
              </td>
              <td>
                <p>Xingu/long, straight-nose plier XV2442</p>
              </td>
              <td>
                <p>Nose material: carbon steel; handle material: rubbered;
        nose length: 11.0 cm; handle length: 9.0 cm; total length: 22.0
        cm; weight: 218 grams</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>Binder clip paper binder</p>
              </td>
              <td>
                <p>Darujo/binder clip</p>
              </td>
              <td>
                <p>Size 40 mm; material steel; color black</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>Portable burner</p>
              </td>
              <td>
                <p>Karla®</p>
              </td>
              <td>
                <p>Weight 404 g; gas consumption 60 g/h; cartridge type 190
        g (not included)</p>
              </td>
            </tr>
          </tbody>
        </table>
      </table-wrap>
      <table-wrap id="table-378">
        <label>Table 3</label>
        <caption>Statistical estimates of mass of different brands of commercial detergents</caption>
        <table>
          <tbody>
            <tr>
              <td rowspan="2">
                <p>
                  <bold>CD</bold>
                </p>
              </td>
              <td colspan="8">
                <p>
                  <bold>Triplicate measurement of
        mass</bold>
                </p>
              </td>
            </tr>
            <tr>
              <td>
                <p>
                  <bold>M<sub>T-P</sub></bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>m<sub>1(g)</sub></bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>m<sub>2(g)</sub></bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>m<sub>3(g)</sub></bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>µ<sub>(g)</sub></bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>Δσ<sub>(g)</sub></bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>σ<sub>(g)</sub></bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>CV(%)</bold>
                </p>
              </td>
            </tr>
            <tr>
              <td>
                <p>A</p>
              </td>
              <td>
                <p>513</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>0</p>
              </td>
              <td>
                <p>0</p>
              </td>
              <td>
                <p>0</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>B</p>
              </td>
              <td>
                <p>522</p>
              </td>
              <td>
                <p>99</p>
              </td>
              <td>
                <p>99</p>
              </td>
              <td>
                <p>99</p>
              </td>
              <td>
                <p>99</p>
              </td>
              <td>
                <p>0</p>
              </td>
              <td>
                <p>0</p>
              </td>
              <td>
                <p>0</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>C</p>
              </td>
              <td>
                <p>522</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>0</p>
              </td>
              <td>
                <p>0</p>
              </td>
              <td>
                <p>0</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>D</p>
              </td>
              <td>
                <p>532</p>
              </td>
              <td>
                <p>97</p>
              </td>
              <td>
                <p>97</p>
              </td>
              <td>
                <p>97</p>
              </td>
              <td>
                <p>97</p>
              </td>
              <td>
                <p>0</p>
              </td>
              <td>
                <p>0</p>
              </td>
              <td>
                <p>0</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>E</p>
              </td>
              <td>
                <p>526</p>
              </td>
              <td>
                <p>96</p>
              </td>
              <td>
                <p>96</p>
              </td>
              <td>
                <p>96</p>
              </td>
              <td>
                <p>96</p>
              </td>
              <td>
                <p>0</p>
              </td>
              <td>
                <p>0</p>
              </td>
              <td>
                <p>0</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>F</p>
              </td>
              <td>
                <p>519</p>
              </td>
              <td>
                <p>98</p>
              </td>
              <td>
                <p>98</p>
              </td>
              <td>
                <p>98</p>
              </td>
              <td>
                <p>98</p>
              </td>
              <td>
                <p>0</p>
              </td>
              <td>
                <p>0</p>
              </td>
              <td>
                <p>0</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>G</p>
              </td>
              <td>
                <p>522</p>
              </td>
              <td>
                <p>97</p>
              </td>
              <td>
                <p>97</p>
              </td>
              <td>
                <p>97</p>
              </td>
              <td>
                <p>97</p>
              </td>
              <td>
                <p>0</p>
              </td>
              <td>
                <p>0</p>
              </td>
              <td>
                <p>0</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>H</p>
              </td>
              <td>
                <p>502</p>
              </td>
              <td>
                <p>99</p>
              </td>
              <td>
                <p>99</p>
              </td>
              <td>
                <p>99</p>
              </td>
              <td>
                <p>99</p>
              </td>
              <td>
                <p>0</p>
              </td>
              <td>
                <p>0</p>
              </td>
              <td>
                <p>0</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>I</p>
              </td>
              <td>
                <p>522</p>
              </td>
              <td>
                <p>99</p>
              </td>
              <td>
                <p>99</p>
              </td>
              <td>
                <p>99</p>
              </td>
              <td>
                <p>99</p>
              </td>
              <td>
                <p>0</p>
              </td>
              <td>
                <p>0</p>
              </td>
              <td>
                <p>0</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>J</p>
              </td>
              <td>
                <p>522</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>0</p>
              </td>
              <td>
                <p>0</p>
              </td>
              <td>
                <p>0</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>µ<sub>P</sub></p>
              </td>
              <td>
                <p>522</p>
              </td>
              <td>
                <p>99</p>
              </td>
              <td>
                <p>99</p>
              </td>
              <td>
                <p>99</p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p> </p>
              </td>
            </tr>
            <tr>
              <td>
                <p>S<sup>2</sup><sub>(g)</sub></p>
              </td>
              <td>
                <p>57.36</p>
              </td>
              <td>
                <p>1.85</p>
              </td>
              <td>
                <p>1.85</p>
              </td>
              <td>
                <p>1.85</p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p> </p>
              </td>
            </tr>
            <tr>
              <td>
                <p>s<sub>(g)</sub></p>
              </td>
              <td>
                <p>7.57</p>
              </td>
              <td>
                <p>1.36</p>
              </td>
              <td>
                <p>1.36</p>
              </td>
              <td>
                <p>1.36</p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p> </p>
              </td>
            </tr>
            <tr>
              <td colspan="9">Note. CD: Commercial detergents;
        M<sub>T-P</sub>: M<sub>Total-Product(g)</sub>; &amp;
        µ<sub>P</sub>: µ<sub>(Product[g])</sub></td>
            </tr>
          </tbody>
        </table>
      </table-wrap>
      <table-wrap id="table-379">
        <label>Table 4</label>
        <caption>Statistical estimates of density of different commercial detergent brands</caption>
        <table>
          <tbody>
            <tr>
              <td>
                <p>
                  <bold>CD</bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>µ<sub>(g)</sub></bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>V<sub>(Graduated Cylinder
        [Ml])</sub></bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>Density<sub>(g mL-1)</sub></bold>
                </p>
              </td>
            </tr>
            <tr>
              <td>
                <p>A</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>1.00</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>B</p>
              </td>
              <td>
                <p>99</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>0.99</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>C</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>1.00</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>D</p>
              </td>
              <td>
                <p>97</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>0.97</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>E</p>
              </td>
              <td>
                <p>96</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>0.96</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>F</p>
              </td>
              <td>
                <p>98</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>0.98</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>G</p>
              </td>
              <td>
                <p>97</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>0.97</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>H</p>
              </td>
              <td>
                <p>99</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>0.99</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>I</p>
              </td>
              <td>
                <p>99</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>0.99</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>J</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>1.00</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>µ<sub>(Products[g])</sub></p>
              </td>
              <td>
                <p>99</p>
              </td>
              <td>
                <p>100</p>
              </td>
              <td>
                <p>0.99</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>S<sup>2</sup>(g)</p>
              </td>
              <td>
                <p>1.85</p>
              </td>
              <td>
                <p>0</p>
              </td>
              <td>
                <p>0.000185</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>s(g)</p>
              </td>
              <td>
                <p>1.36</p>
              </td>
              <td>
                <p>0</p>
              </td>
              <td>
                <p>0.0136</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>CV(%)</p>
              </td>
              <td>
                <p>1.37%</p>
              </td>
              <td>
                <p>0.00%</p>
              </td>
              <td>
                <p>1.37%</p>
              </td>
            </tr>
            <tr>
              <td colspan="4">Note. CD: Commercial detergents</td>
            </tr>
          </tbody>
        </table>
      </table-wrap>
      <table-wrap id="table-380">
        <label>Table 5</label>
        <caption>Statistical Estimates of viscosity with standard viscometer Ford no. 4</caption>
        <table>
          <colgroup>
            <col width="11%" />
            <col width="11%" />
            <col width="11%" />
            <col width="11%" />
            <col width="11%" />
            <col width="11%" />
            <col width="11%" />
            <col width="11%" />
            <col width="11%" />
          </colgroup>
          <tbody>
            <tr>
              <td rowspan="2">
                <p>
                  <bold>CD</bold>
                </p>
              </td>
              <td colspan="8">
                <p>
                  <bold>Flow time–standard viscometer Ford no.
        4</bold>
                </p>
              </td>
            </tr>
            <tr>
              <td>
                <p>
                  <bold>t1<sub>(s)</sub></bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>t2<sub>(s)</sub></bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>t3<sub>(s)</sub></bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>µ<sub>(s)</sub></bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>Δσ<sub>(s)</sub></bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>σ<sub>(s)</sub></bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>CV(%)</bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>Ѵ<sub>1
        (mm</sub><sup>2</sup> s<sup>-1</sup><sub>)</sub></bold>
                </p>
              </td>
            </tr>
            <tr>
              <td>
                <p>A</p>
              </td>
              <td>
                <p>105.74</p>
              </td>
              <td>
                <p>110.41</p>
              </td>
              <td>
                <p>108.34</p>
              </td>
              <td>
                <p>108.34</p>
              </td>
              <td>
                <p>3.65</p>
              </td>
              <td>
                <p>1.91</p>
              </td>
              <td>
                <p>1.76%</p>
              </td>
              <td>
                <p>399.82</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>B</p>
              </td>
              <td>
                <p>60.43</p>
              </td>
              <td>
                <p>62.96</p>
              </td>
              <td>
                <p>61.01</p>
              </td>
              <td>
                <p>61.01</p>
              </td>
              <td>
                <p>1.17</p>
              </td>
              <td>
                <p>1.08</p>
              </td>
              <td>
                <p>1.77%</p>
              </td>
              <td>
                <p>217.60</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>C</p>
              </td>
              <td>
                <p>78.51</p>
              </td>
              <td>
                <p>80.26</p>
              </td>
              <td>
                <p>80.32</p>
              </td>
              <td>
                <p>80.26</p>
              </td>
              <td>
                <p>0.70</p>
              </td>
              <td>
                <p>0.84</p>
              </td>
              <td>
                <p>1.05%</p>
              </td>
              <td>
                <p>291.71</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>D</p>
              </td>
              <td>
                <p>58.82</p>
              </td>
              <td>
                <p>59.35</p>
              </td>
              <td>
                <p>60.55</p>
              </td>
              <td>
                <p>59.35</p>
              </td>
              <td>
                <p>0.52</p>
              </td>
              <td>
                <p>0.72</p>
              </td>
              <td>
                <p>1.22%</p>
              </td>
              <td>
                <p>211.21</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>E</p>
              </td>
              <td>
                <p>47.77</p>
              </td>
              <td>
                <p>48.17</p>
              </td>
              <td>
                <p>49.07</p>
              </td>
              <td>
                <p>48.17</p>
              </td>
              <td>
                <p>0.30</p>
              </td>
              <td>
                <p>0.54</p>
              </td>
              <td>
                <p>1.13%</p>
              </td>
              <td>
                <p>168.17</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>F</p>
              </td>
              <td>
                <p>81.44</p>
              </td>
              <td>
                <p>80.12</p>
              </td>
              <td>
                <p>81.2</p>
              </td>
              <td>
                <p>81.2</p>
              </td>
              <td>
                <p>0.33</p>
              </td>
              <td>
                <p>0.57</p>
              </td>
              <td>
                <p>0.71%</p>
              </td>
              <td>
                <p>295.33</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>G</p>
              </td>
              <td>
                <p>51.24</p>
              </td>
              <td>
                <p>52.97</p>
              </td>
              <td>
                <p>50.01</p>
              </td>
              <td>
                <p>51.24</p>
              </td>
              <td>
                <p>1.47</p>
              </td>
              <td>
                <p>1.21</p>
              </td>
              <td>
                <p>2.37%</p>
              </td>
              <td>
                <p>179.99</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>H</p>
              </td>
              <td>
                <p>68.61</p>
              </td>
              <td>
                <p>67.07</p>
              </td>
              <td>
                <p>68.18</p>
              </td>
              <td>
                <p>68.18</p>
              </td>
              <td>
                <p>0.42</p>
              </td>
              <td>
                <p>0.65</p>
              </td>
              <td>
                <p>0.95%</p>
              </td>
              <td>
                <p>245.21</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>I</p>
              </td>
              <td>
                <p>55.09</p>
              </td>
              <td>
                <p>54.07</p>
              </td>
              <td>
                <p>54.1</p>
              </td>
              <td>
                <p>54.1</p>
              </td>
              <td>
                <p>0.22</p>
              </td>
              <td>
                <p>0.47</p>
              </td>
              <td>
                <p>0.88%</p>
              </td>
              <td>
                <p>191.00</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>J</p>
              </td>
              <td>
                <p>45.17</p>
              </td>
              <td>
                <p>45.94</p>
              </td>
              <td>
                <p>47.14</p>
              </td>
              <td>
                <p>45.94</p>
              </td>
              <td>
                <p>0.66</p>
              </td>
              <td>
                <p>0.81</p>
              </td>
              <td>
                <p>1.76%</p>
              </td>
              <td>
                <p>159.58</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>µ<sub>(s)</sub></p>
              </td>
              <td>
                <p>59.63</p>
              </td>
              <td>
                <p>61.16</p>
              </td>
              <td>
                <p>60.78</p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p>214.41</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>S<sup>2</sup><sub>(s)</sub></p>
              </td>
              <td>
                <p>316.15</p>
              </td>
              <td>
                <p>346.18</p>
              </td>
              <td>
                <p>332.77</p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p>5,010.35</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>s<sub>(s)</sub></p>
              </td>
              <td>
                <p>17.78</p>
              </td>
              <td>
                <p>18.61</p>
              </td>
              <td>
                <p>18.24</p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p>70.78</p>
              </td>
            </tr>
            <tr>
              <td>
                <p>CV(%)</p>
              </td>
              <td>
                <p>29.82%</p>
              </td>
              <td>
                <p>30.42%</p>
              </td>
              <td>
                <p>30.01%</p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p> </p>
              </td>
              <td>
                <p>33.01%</p>
              </td>
            </tr>
            <tr>
              <td colspan="9">Note. CD: Commercial detergents</td>
            </tr>
          </tbody>
        </table>
      </table-wrap>
      <table-wrap id="table-381">
        <label>Table 6</label>
        <caption>Statistical estimates of viscosity with the alternative viscometer</caption>
        <table>
          <colgroup>
            <col width="11%" />
            <col width="11%" />
            <col width="11%" />
            <col width="11%" />
            <col width="11%" />
            <col width="11%" />
            <col width="11%" />
            <col width="11%" />
            <col width="11%" />
          </colgroup>
          <tbody>
            <tr>
              <td rowspan="2">
                <p>
                  <bold>CD</bold>
                </p>
              </td>
              <td colspan="8">
                <p>
                  <bold>Flow time–alternative
        viscometer</bold>
                </p>
              </td>
            </tr>
            <tr>
              <td>
                <p>
                  <bold>t1<sub>(s)</sub></bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>t2<sub>(s)</sub></bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>t3<sub>(s)</sub></bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>µ<sub>(s)</sub></bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>Δσ<sub>(s)</sub></bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>σ<sub>(s)</sub></bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>CV(%)</bold>
                </p>
              </td>
              <td>
                <p>
                  <bold>Ѵ<sub>2
        (mm</sub><sup>2</sup> s<sup>-1</sup><sub>)</sub></bold>
                </p>
              </td>
            </tr>
            <tr>
              <td style="vertical-align: bottom">
                <p>A</p>
              </td>
              <td style="vertical-align: bottom">
                <p>97.13</p>
              </td>
              <td style="vertical-align: bottom">
                <p>96.05</p>
              </td>
              <td style="vertical-align: bottom">
                <p>98</p>
              </td>
              <td style="vertical-align: bottom">
                <p>97.13</p>
              </td>
              <td style="vertical-align: bottom">
                <p>0.64</p>
              </td>
              <td style="vertical-align: bottom">
                <p>0.80</p>
              </td>
              <td style="vertical-align: bottom">
                <p>0.82%</p>
              </td>
              <td style="vertical-align: bottom">
                <p>356.66</p>
              </td>
            </tr>
            <tr>
              <td style="vertical-align: bottom">
                <p>B</p>
              </td>
              <td style="vertical-align: bottom">
                <p>48.45</p>
              </td>
              <td style="vertical-align: bottom">
                <p>46.59</p>
              </td>
              <td style="vertical-align: bottom">
                <p>46.64</p>
              </td>
              <td style="vertical-align: bottom">
                <p>46.64</p>
              </td>
              <td style="vertical-align: bottom">
                <p>0.75</p>
              </td>
              <td style="vertical-align: bottom">
                <p>0.87</p>
              </td>
              <td style="vertical-align: bottom">
                <p>1.86%</p>
              </td>
              <td style="vertical-align: bottom">
                <p>162.28</p>
              </td>
            </tr>
            <tr>
              <td style="vertical-align: bottom">
                <p>C</p>
              </td>
              <td style="vertical-align: bottom">
                <p>53.06</p>
              </td>
              <td style="vertical-align: bottom">
                <p>51.59</p>
              </td>
              <td style="vertical-align: bottom">
                <p>52.48</p>
              </td>
              <td style="vertical-align: bottom">
                <p>52.48</p>
              </td>
              <td style="vertical-align: bottom">
                <p>0.37</p>
              </td>
              <td style="vertical-align: bottom">
                <p>0.60</p>
              </td>
              <td style="vertical-align: bottom">
                <p>1.15%</p>
              </td>
              <td style="vertical-align: bottom">
                <p>184.76</p>
              </td>
            </tr>
            <tr>
              <td style="vertical-align: bottom">
                <p>D</p>
              </td>
              <td style="vertical-align: bottom">
                <p>37.42</p>
              </td>
              <td style="vertical-align: bottom">
                <p>38.06</p>
              </td>
              <td style="vertical-align: bottom">
                <p>37.57</p>
              </td>
              <td style="vertical-align: bottom">
                <p>37.57</p>
              </td>
              <td style="vertical-align: bottom">
                <p>0.07</p>
              </td>
              <td style="vertical-align: bottom">
                <p>0.27</p>
              </td>
              <td style="vertical-align: bottom">
                <p>0.73%</p>
              </td>
              <td style="vertical-align: bottom">
                <p>127.36</p>
              </td>
            </tr>
            <tr>
              <td style="vertical-align: bottom">
                <p>E</p>
              </td>
              <td style="vertical-align: bottom">
                <p>29.2</p>
              </td>
              <td style="vertical-align: bottom">
                <p>28.59</p>
              </td>
              <td style="vertical-align: bottom">
                <p>29.93</p>
              </td>
              <td style="vertical-align: bottom">
                <p>29.2</p>
              </td>
              <td style="vertical-align: bottom">
                <p>0.30</p>
              </td>
              <td style="vertical-align: bottom">
                <p>0.55</p>
              </td>
              <td style="vertical-align: bottom">
                <p>1.88%</p>
              </td>
              <td style="vertical-align: bottom">
                <p>95.13</p>
              </td>
            </tr>
            <tr>
              <td style="vertical-align: bottom">
                <p>F</p>
              </td>
              <td style="vertical-align: bottom">
                <p>71.75</p>
              </td>
              <td style="vertical-align: bottom">
                <p>69.52</p>
              </td>
              <td style="vertical-align: bottom">
                <p>70.43</p>
              </td>
              <td style="vertical-align: bottom">
                <p>70.43</p>
              </td>
              <td style="vertical-align: bottom">
                <p>0.84</p>
              </td>
              <td style="vertical-align: bottom">
                <p>0.92</p>
              </td>
              <td style="vertical-align: bottom">
                <p>1.30%</p>
              </td>
              <td style="vertical-align: bottom">
                <p>253.87</p>
              </td>
            </tr>
            <tr>
              <td style="vertical-align: bottom">
                <p>G</p>
              </td>
              <td style="vertical-align: bottom">
                <p>21.4</p>
              </td>
              <td style="vertical-align: bottom">
                <p>21.46</p>
              </td>
              <td style="vertical-align: bottom">
                <p>21.25</p>
              </td>
              <td style="vertical-align: bottom">
                <p>21.4</p>
              </td>
              <td style="vertical-align: bottom">
                <p>0.01</p>
              </td>
              <td style="vertical-align: bottom">
                <p>0.09</p>
              </td>
              <td style="vertical-align: bottom">
                <p>0.41%</p>
              </td>
              <td style="vertical-align: bottom">
                <p>65.10</p>
              </td>
            </tr>
            <tr>
              <td style="vertical-align: bottom">
                <p>H</p>
              </td>
              <td style="vertical-align: bottom">
                <p>28.45</p>
              </td>
              <td style="vertical-align: bottom">
                <p>28.15</p>
              </td>
              <td style="vertical-align: bottom">
                <p>28.33</p>
              </td>
              <td style="vertical-align: bottom">
                <p>28.33</p>
              </td>
              <td style="vertical-align: bottom">
                <p>0.02</p>
              </td>
              <td style="vertical-align: bottom">
                <p>0.12</p>
              </td>
              <td style="vertical-align: bottom">
                <p>0.44%</p>
              </td>
              <td style="vertical-align: bottom">
                <p>91.78</p>
              </td>
            </tr>
            <tr>
              <td style="vertical-align: bottom">
                <p>I</p>
              </td>
              <td style="vertical-align: bottom">
                <p>18.12</p>
              </td>
              <td style="vertical-align: bottom">
                <p>18.74</p>
              </td>
              <td style="vertical-align: bottom">
                <p>19.09</p>
              </td>
              <td style="vertical-align: bottom">
                <p>18.74</p>
              </td>
              <td style="vertical-align: bottom">
                <p>0.16</p>
              </td>
              <td style="vertical-align: bottom">
                <p>0.40</p>
              </td>
              <td style="vertical-align: bottom">
                <p>2.14%</p>
              </td>
              <td style="vertical-align: bottom">
                <p>54.86</p>
              </td>
            </tr>
            <tr>
              <td style="vertical-align: bottom">
                <p>J</p>
              </td>
              <td style="vertical-align: bottom">
                <p>8.06</p>
              </td>
              <td style="vertical-align: bottom">
                <p>8.42</p>
              </td>
              <td style="vertical-align: bottom">
                <p>8.37</p>
              </td>
              <td style="vertical-align: bottom">
                <p>8.37</p>
              </td>
              <td style="vertical-align: bottom">
                <p>0.03</p>
              </td>
              <td style="vertical-align: bottom">
                <p>0.16</p>
              </td>
              <td style="vertical-align: bottom">
                <p>1.90%</p>
              </td>
              <td style="vertical-align: bottom">
                <p>14.94</p>
              </td>
            </tr>
            <tr>
              <td style="vertical-align: bottom">
                <p>µ<sub>(s)</sub></p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p>111.24</p>
              </td>
            </tr>
            <tr>
              <td style="vertical-align: bottom">
                <p>S<sup>2</sup><sub>(s)</sub></p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p>9,540.07</p>
              </td>
            </tr>
            <tr>
              <td style="vertical-align: bottom">
                <p>s<sub>(s)</sub></p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p>97.6733</p>
              </td>
            </tr>
            <tr>
              <td style="vertical-align: bottom">
                <p>CV(%)</p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p> </p>
              </td>
              <td style="vertical-align: bottom">
                <p>87.80%</p>
              </td>
            </tr>
            <tr>
              <td colspan="9" style="vertical-align: bottom">Note. CD:
        Commercial detergents</td>
            </tr>
          </tbody>
        </table>
      </table-wrap>
    </sec>
  </back>
</article>