Project-Based Learning (PjBL) Worksheet on the Production of Whey Kefir Paper Soap

Students often ask about the practical application of concepts and knowledge gained from their coursework. Practicum worksheets provide an opportunity for students to engage in hands-on learning, identify their strengths, learn from their mistakes, and develop enhanced competence as learners. This study aims to develop an effective and valid worksheet on PjBL in whey kefir paper soap. Research and Development (R&D) is used as a method. Worksheet designs were produced using three formulas depending on production techniques. Based on Indonesia National Standard, Formula 1 (8% whey kefir) demonstrated the best qualities of the paper soap. The expert validation test of the worksheets showed a r count value of 0.84 (valid). The percentage of worksheet answers was very good (88%). Student worksheet feasibility test results showed a r count value of 0.84 (feasible). Practicum worksheets are categorized as very suitable for use as a learning media in an organic chemistry course.


Introduction
In Chemistry learning process, students' skills are needed for understanding, mastering concepts, and resolving questions or problems (Khaeruman et al., 2019).Besides, the experimental activities will give students a better understanding of the concept and make learning more meaningful.In order practicum could be carried out properly, woorksheet is one of media needed to help.Therefore, a good worksheet needs to be designed based on specifications and according to the topic being practiced (Rahmatullah & Fadilah, 2017).
Previous studies have shown that PjBL worksheets can improve students' creative thinking skills in molecular modeling material.The average score of students when completing worksheet reaches 85 which is categorized as very creative (Apipah et al., 2019).Meanwhile, other research proves that the steps in PjBL worksheets are able to develop scientific attitudes and real abstract concepts, especially in chemistry (Tazqiyah et al., 2021).
One of an abstract concept with a concrete example in chemistry learning is saponification reactions.It's one of the concepts studied in lipid material in organic chemistry course.Saponification is a reaction between an ester and base that converts into alcohol (glycerol) and soap as the final product.(Arniezca et al., 2017).
There are three techniques for making paper soap: using plasticizers, film foaming agents, or paper membranes.The most commonly used plasticizer is glycerin (Wati et al., 2020).The process of making soap is divided into hot and cold processes.The temperature of the hot process to mix the base solution and oil or fat is 70°C.Whereas in the cold process, the mixing temperature is done at 32-35°C.This temperature has affected curing time (time to drying soap).The cold process has a longer curing time than the hot process, which is ± 2-3 weeks (Sastrawidana et al., 2020).
Nowadays, many people are more interested in using soap made from herbal ingredients because of its bioactivity properties, and natural ingredients in it has lower or even nonexistent side effects for users (Sari et al., 2017); an example is whey kefir.Whey kefir is one part of the kefir product that has various benefits.Whey kefir contains 0.8-1% of protein, 65% of β-lactoglobulin, 25% of αlactalbumin, 8% of bovine serum albumin, and immunoglobulin (Kurniati et al., 2016).In soap making, whey kefir works as skin lightener and inhibits melanin synthesis in it (Helsy et al., 2018).
Based on previous research, lemon peel contains a D-limonene compound that functions as aromatherapy and can improve the soap quality.In the pharmaceutical industry, essential oils of lemon peel have activity as anti-bacterial (Suryafly & Aziz, 2019).This research develops a PjBL worksheet for making soap with whey kefir as a natural ingredient based on a saponification reaction, with adding a plasticizer as glycerin to produce paper soap.

PjBL
worksheet is student-centered worksheets to develop thinking skills.It contains questions that direct students to discover and construct concepts (Wirda et al., 2018).Also, the PjBL worksheet conducts questions with learning stages that lead to the final product production goal.In PjBL worksheets, discourses, tools, and materials guide students in designing and conducting experiments, also communicating the result of products/projects (Apipah et al., 2019).PjBL can motivate low-achieving students to be more interested in learning and reduce the achievement gap (Mutakinati 2018).Based on this description, PjBL worksheet is appropriate to be applied in chemistry learning, especially in abstract concepts with concrete examples.Therefore, developing PjBL worksheets is appropriate for the concept of saponification reactions in lipid material in an organic chemistry course.

Research Method
This research use R&D (Research and Development) method.According to Borg and Gall, it is divided into four stages which are preliminary studies, development model, validation, and revision (Hanafi, 2017).
Preliminary study was carried out through analysis of journals relevant to the technique of making paper soap and the benefits of using kefir whey.At the development stage, worksheets designs are made based on manufacturing techniques and materials that have been analyzed in the first stage.After developing the worksheet, validation is carried out to made a valid and effective worksheet.
Several expert lecturers validated worksheets.The aspects seen in validation test consist of display, content or language, and construct.The resulting data were analyzed by comparing the due diligence (r) results with the critical value.The worksheet categorizes as valid category if the value of rcount ≥ 0.3 (Ernawati & Sukardiyono, 2017).The research procedure can be seen in Figure 1, and the procedure for making whey kefir soap can be seen in Figure 2.

Result and Discussion
The results are presented in two sections: the form of a worksheet design, and the worksheet validation results.

Worksheet Design
PjBL worksheet has six learning stages which are analyzing problems, making designs, carrying out research, compiling prototypes, evaluating products, and product finalization (Apipah et al., 2019).First page of the worksheets is provided a student identity format, activity objectives, and instructions for working on it.Then on the next page, a discourse is given.The discourse presented contains of explanation about advantage of paper soap, manufacturing process, materials used, as well as the quality testing techniques of the soap produced.At this early stage, questions were also given that directed students to formulate problems, hypothesize, and conduct experiments.
The second stage is to design.Students are directed to write down the tools and materials as well as procedures in making paper soap based on the pictures presented.Pictures of tools and materials are presented along with the stages of making kefir whey paper soap as shown in Figure 3 and 4.  The last stage was finalization and publication; students were directed to present the products that had been made.At this stage, students were instructed to publish the product by video, then upload it to the YouTube application and attach the video link to the worksheet.

Worksheet Validation Test Results
PjBL worksheets that have been prepared are then validated by three expert lecturers to ensure that the worksheets developed with categorized as valid or not.The results of validation test from the three validators can be seen in Table 1.In addition, worksheets has function as supporting learning media that can optimize students' ability to understand the material and make students active during the practicum (Subarkah et al., 2015).
The validation carried out covers four important aspects, which are presentation, construct, content and questions.The presentation aspect is shown in questions one and two regarding the coherence of concepts and regularity between practicum activities (PjBL stage) which are said to be valid.Assessment of the construct aspect is shown in questions number three and four regarding the use of sentences that are easy to understand and pictures that are clear and according to the rcount value of 0.83 which is declared valid.
The content aspect is shown in questions number five to twelve and get valid results.
The validation results of question number 11 show that the procedure for manufacturing kefir whey paper soap is easy to do according on the tools and materials that are easy to find in the surrounding environment.In the last aspect, the questions shown in numbers 13 and 14 regarding the suitability of the questions with the material, indicators, and learning objectives are declared valid.
According to Table 1, PjBL worksheet has a value of 0.84 rcount which are considered valid.This shows that the worksheet developed satisfies the requirements of a proper worksheet.

Feasibility Test Results
After being validated and categorized as a valid worksheet, the next step is to carry out a limited test on 15 students in fourth semester chemistry education that are divided into three groups.The percentage of answer value are show in Table 2.According to Table 3, the scores obtained by students in the limited test were presented.In the problem analysis stage, the percentage obtained was 70%.This stage contained questions regarding reaction equations, manufacturing techniques, and testing on manufacturing paper soap and questions regarding the formulation of the problem, hypothesis, and the purpose of the experiment.According to respondents, adding the size (amount) of materials used in making paper soap was necessary.At the project design stage, students wrote down the tools and materials used in making whey kefir paper soap, and a score of 100% was obtained.
After writing down the tools and materials needed, students conducted research by designing experiments (making procedures in flowcharts), writing down the results of observations in tabular form, and analyzing the observed data.At this stage, the percentage value was 91%.In the research conducted by Apipah (2019), an average value of 86% was obtained at the research stage with PjBL worksheets in molecular model material.This data showed an increase in the average value of worksheet based on manufacturing projects whey kefir paper soap as herbal soap.
In the fourth stage, namely compiling a draft/prototype, students test the paper soap they produce.Students only do simple tests, namely foam stability and pH value.At this stage, the percentage value is 100.Then in the fifth stage, the percentage value is 80.
Students carry out a product assessment: comparing paper soap made with soap that followed the SNI.In the final stage, the percentage value was 87%.Students were directed to publish their project as a video uploaded to the YouTube application and attach the video link to the worksheet.The project display uploaded is presented in Figure 9.This worksheet development followed the stages of PjBL and made it easier to understand the concept.The average percentage obtained from filling out this worksheet was 88%, categorized as very feasible to apply (Ernawati et al., 2017).Hence, students were given a questionnaire containing the statements to determine the worksheet feasibility.It is shown in Table 3.Based on the data in Table 3, the lowest rcount value was 0.75 in statement number 6 regarding the discourse presented.The discourse explained the phenomenon of saponification and the ingredients used in soap making.According to the respondent, in the discourse, it was necessary to add the quantity of the ingredients used in making soap.
Moreover, statements 1, 3, 4, 7, 8, 9, and 10 got rcount of 0.83.This statement concerns the appearance of the worksheet, the images presented, and the language used in the worksheet.The appearance and images on the worksheet were made more colorful and clearer to increase interest in the work.The language used was clear and easy to understand.The largest rcount value was 0.92 in statements number 3 and 5. Based on these statements, the worksheet was effective and valid in helping students to study the saponification topic.

Conclusion
Natural ingredients used such as VCO, kefir whey, and essential oil from lemon peels are proven to improve the quality of paper soap.
Based on Indonesia National Standard, the best paper soap was obtained from the addition of 8% whey kefir (F1 formulation) with a pH of 8 and the value of foam stability was 83%.
Meanwhile, the PjBL worksheet includes six stages: analyzing the problem, designing the project, conducting research, evaluating the product, and finalizing and publishing the product.The worksheet has discourse that can direct students to conduct experiments.The PjBL worksheet on making whey kefir paper soap as herbal soap was declared valid by obtaining the rcount of 0.84 and categorized as very suitable for use as a learning media in organic chemistry courses.
Figure 1.Research Procedure

Figure 3 .Figure 4 .
Figure 3. Making Paper Soap using Hot Process

Figure 9 .
Figure 9. Product Finalization and Publication

Table 2 . Percentage of Answer Value on Worksheet
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