Workshop on 4 April 2019 – chemistry experiment in the science laboratory (saponification)

Preparation in the science lab1

For a Bachelor’s degree in Bilingual Teaching2 at the PH Karlsruhe, a stay abroad of 20 weeks is required. There are no specifications where to go, but the chosen country or project has to be connected to one of the two offered target languages at the PH Karlsruhe: English or French.

We, Rebekka Vogt and Vanessa Wecker (Team VIII), are enrolled in this Bilingual Teaching program. Rebekka studies English in combination with biology and Vanessa studies English in combination with chemistry.  For a teacher of bilingual teaching it is important to use possibilities for cultural learning and teaching because it “enables [us as teacher trainees] to be effective with students from cultures other than [our] own” (cf. NEA, “Why Cultural Competence?”, 2019).
Staying abroad usually extends and deepens language competences and provides cultural learning possibilities. Therefore, it is necessary to stay abroad for a longer period of time. During our stay abroad, an individual project has to be carried out and documented, as a “milestone in order to become a teacher for bilingual teaching” (“Meilenstein auf dem Weg zur BLL/ CLIL – Lehrkraft”), which is to specify and reflect our experiences and newly gained knowledge and competences (C. Rittersbacher 2016, guideline for unit test).

Out of the many different offers the PH Karlsruhe provides, the project “The Laos Experience” attracted us the most. Not only would we experience, live, and work amongst the Lao people and culture, but we would be also able to expand our practical skills at teaching because of the opportunity of gaining a better understanding of materials and ingredients. Furthermore, we would experience new ways of approaching problems. Due to the fact that neither of us speaks the Laotian language, we had to find ways to communicate with the Laotian pupils without relying on language. This includes photo material, gestures, and drawings on the blackboard.
Also, learning about other cultures fosters intercultural understanding. The “bi-directional (tandem) teaching and learning” project in Laos caught our interest due to the fact that it might be the most fitting opportunity to achieve these required competences and gain this knowledge, all combined.

In fact, in Laos we had the chance to offer the “Science Lab” for Activity Time at the Lower Secondary School Ban Phang Heng, which means we conducted experiments for interested pupils every Monday and Thursday from 3:15 – 4:00 p.m. The Science Lab was a great opportunity for us to practise our former knowledge about teaching science. This was the reason why Vanessa decided to do her bilingual project at Ban Phang Heng Lower Secondary School.

Before leaving for our stay abroad, Vanessa did some research on how chemistry experiments for secondary students could be implemented in class and also on which experiments might be interesting for the Lao pupils. She did this by comparing the inventory list of the Science Lab and experiments that had already been uploaded on alfresco3 by former teams. Often, in Germany, chemistry is perceived by students as “too hard” or “not imaginable”, and because of this Vanessa chose a topic that has a relevance in everyday life – saponification.

Saponification derives from the Latin word “sapo”, which means soap (cf. Clugston and Flemming, 2000: 97).  After some research, Vanessa came up with an easy experiment in order to demonstrate the process of saponification: Making your own soap with ingredients that a lot of people already have at home. This way, the pupils would have the opportunity to make their own soap at home later on as well if they wanted to.


The process of making soap


All we needed was some distilled water, some baking soda, and a candle. The candle needs to contain stearin4 (otherwise this experiment would not work). Additional ingredients, for scent or color, might be spices such as turmeric5 or paprika powder6 (capsicum). For a nice smell, coconut oil or any other essential oil can be added (Chevallier, 2011: 55). We brought some ingredients along from Germany, but all ingredients can also be found in a western supermarket in Vientiane.

  • distilled water
  • baking soda
  • candle (containing stearin)
  • additional spices: turmeric or paprika powder
  • additional smell: essential oils (e.g. coconut oil)


From the teachers’ kitchen at the school, Rebekka and Vanessa organised a cooking pot, spoons, and glasses. We also used measuring cylinders and scales from the Science Lab inventory. Vanessa brought some pH indicator paper with her from Germany.

We started setting up the experiment, and as soon as everyone had put on their laboratory coats, we were ready for making our own soap! After the production, we handed out a worksheet to the pupils which contained step-by-step instructions with pictures. The first part of the worksheet shows a picture of the material needed, which the pupils have to match with the right English word. With the legendary help of our tireless partner Ms Saysamone Singhalath, it was possible for us to add the Lao translations to our worksheet.

For the first step of our experiment, the pupils had to pour a measured amount of distilled water into the cooking pot. Then, the natron needed to be weighed and added to the cooking pot with the distilled water. One can also use baking soda instead of Kaiser Natron7 and then the soap might turn out slightly different, concerning its chemical composition. Kaiser Natron is NaHCO3, whilst baking soda contains acidifiers in addition to the NaHCO3. The pupils were made aware of that fact as well. For this experiment, we used Kaiser Natron.

Since there is only one Bunsen burner8 in the Science Lab, the next step was done by Vanessa. For safety reasons, she melted the candle, which contained stearin, at the desk up front. After, the mixture of distilled water and natron was heated up by the pupils. As soon as the bubbling decreased, melted wax was added to the cooking pot. We all were able to see a lot of foam. At last, the soap needed to be scooped out of the foam by the pupils and put into small containers, which they received beforehand.

In order to demonstrate to the pupils that this soap was usable and not hazardous, we gave each student a small piece of pH indicator paper.

The pH indicator paper is a useful tool to measure the hydrogen ion concentration in a water solution. A low pH indicates solutions with a high concentration of hydrogen ions, whereas a high pH  indicates solutions with low concentrations of hydrogen ions. Self-made soaps are usually between a pH of 8 and 10, but can go up near a pH of 11.

Each one of them put their little slip of paper in their soap containers. After confirming that their soap was eudermic within the pH range of 9 and 10, it was used for washing their hands.

We arranged some optional ingredients for smell and color at the teacher’s desk. Now it was up to the pupils to upgrade their soap to their own liking by adding different spices or scents.

The process of modifying their individual soaps appeared to be so interesting that the pupils got really curious about the possible combinations of color and scent. They even used the other pupils’ soaps to compare which soap was the more colorful and odorous!

After cleaning up the Science Lab, the pupils went home with their little soap containers and some pH indicator paper.

The experiment appeared to be an exciting experience for the pupils, as it gave them the opportunity to gain a better understanding of the ingredients and processes involved in saponification. They were amazed to see how easy it is to make their own soap.

It was important to us that the pupils would be able to deepen their understanding of making their own soap by doing it themselves. Due to the fact that there are a lot of chemicals used for soap in general, we wanted to show how to make their own soap without the use of a lot of chemicals,9 which is why this experiment can also easily be done at home. The process of making soap is quite simple, and to make things yourself allows children to truly appreciate their own work.

Conducting the experiment was a very interesting experience for us, too. Not only did we learn how to make soap ourselves, but we also learned about the importance of adapting teaching material in the classroom accordingly. For future teachers of English, it is important to act on the fact that not every pupil has the same, “general” (cultural) background.10 Therefore, it is paramount  to provide several ways of adapted learning in a classroom, which we call “differentiation“.
An experiment needs to be adapted in the same way. Thereby, pupils with different levels of knowledge will all be able to follow the process. This is why we chose an experiment that did not need weeks of preparation in order to understand the chemical process.

We hope that some of the pupils will use their new knowledge and make their own soap again!


Text & photos by R. Vogt & V. Wecker



1 Other articles related to science and educational science on this blog: “Our Cooperation with the Research Institute of Educational Sciences (RIES) by I. Martin, D. Schrep, and A. Broghammer” (23 February 2017);
Science lab activity time at Ban Phang Heng Secondary School by R. Dengler” (18 March 2017);
A workshop for the science teachers at Ban Phang Heng Secondary School by R. Dengler and V. Golla” (1 April 2017); “Busy hands, busy brains – Hands-on science lessons at Ban Phang Heng Secondary School by V. Golla” (14 November 2017);
Workshop on 5 December 2017 – How to embed experiments in science lessons by R. Dengler and V. Golla” (26 December 2017).

2 Bilingual education is defined as teaching content in two languages. In this case, the amount of each language used (the native and secondary language) can be varied in accordance with the program model.  (Wikipedia (2019). “Bilingual education“. (last accessed 18 November 2019))

3 “Alfresco” is the name of our “CMS” (Content Management System), i.e. a working platform for volunteers participating in “The Laos Experience”. It is used as an internal repository of all the project documents ever produced, so each team member can access and profit from the work of those that came before.

By heating up the NaHCO3 (Kaiser Natron), NaHCO3 disintegrates into Na2CO3. Stearic acid is a component of candle wax and combines with Na2CO3. Therefore, stearic acid is an essential ingredient to this experiment.

5 Turmeric powder comes from the roots of the plant “Curcuma longa”. Due to its yellow color it is used in many Asian dishes. (Wikipedia (2019). “Turmeric“. (last accessed 14 September 2019))

6 Paprika powder “is a ground spice made from dried red fruits of the larger and sweeter varieties of the plant Capsicum annuum, called bell pepper or sweet pepper. Sweet paprika is mostly composed of the pericarp, with more than half of the seeds removed, whereas hot paprika contains some seeds, stalks, placentas, and calyces. The red, orange or yellow color of paprika is due to its content of carotenoids.” (Wikipedia (2019). “Paprika“. (last accessed 14 September 2019))

Both Kaiser Natron and baking soda are grounded on sodium and carbonates. The chemical formula for sodium is NaHCO3, whereas the chemical formula for soda is Na2CO3. With soda, the carbonate combines with a sodium atom and a hydrogen atom. The soda replaces the hydrogen atom with another sodium atom.

8 “A Bunsen burner, named after Robert Bunsen, is a common piece of laboratory equipment that produces a single open gas flame, which is used for heating, sterilization, and combustion.” (Wikipedia (2019). “Bunsen burner“. (last accessed 14 September 2019))

Most soap recipes require either caustic soda (NaOH) or caustic potash (KOH). These ingredients can vitriolise skin and eyes, which is why we wanted to avoid them in our experiment. In addition to that, a lot of Lao cosmetics advertise skin-whitening, which we noticed during our visits to markets or stores. However, a few of these ingredients might cause long-term damage to one’s skin.

10 Multicultural classrooms embrace diversity, support cultural differences and different family backgrounds. This can encourage effective learning for pupils of diverse backgrounds.



Chevallier, L. & S. (32014 [2011]). Seifen selbst gemacht – Einfach & natürlich. Graz: Leopold Stocker Verlag.

Clugston, M. & Flemming, R. (2000). Advanced Chemistry. Oxford/New York.

Rittersbacher, C. (2016). Modulprüfung Eula PO2015 – M1 Bachelor. Karlsruhe: University of Education Karlsruhe.

NEA (2019). “Why Cultural Competence?”. (last accessed 24 November 2019).

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