The principle of sustainability and the concept of sustainable development have been the guiding principles of international environmental and development policy since the Earth Summit of Rio de Janeiro in 1992. The concept of sustainable development is defined as “development that meets the needs of the present without compromising the ability of future generations to meet their own needs” (World Commission on Environment and Development, 1987, p. 54). This concept has two principles as “intergenerational equity” and “intragenerational equity”. For the intergenerational equity, each generation has the same chance for development. For the intragenerational equity, generation lives in different regions and at different levels of development in terms of health, prosperity and security. These two principles form the basis for achieving sustainable development. Additionally, sustainable development has three dimensions as environmental integrity means that not more natural resources are utilized than can be regenerated, economic viability refers to the production and consumption of prosperity, and just society has the intent of improving the standard of living and refers to the situation within the particular society (Benninghaus, Kremer, & Sprenger 2018).

Global water scarcity is the center of sustainable development. 6^th goal of the 17 Sustainable Development Goals of the UN (United Nations, 2016) planned to be reached in 2030 is stated as follows: “Ensure availability and sustainable management of water and sanitation for all”. Today, millions of people are deprived of adequate water and water services: 2.6 billion people are deprived of hygiene facilities; 884 million people do not have access to clean water. In addition to direct use of water in this way, water is also indirectly used and this indirect use of water is often ignored by consumers. Every product we use or consume in our daily life contains different proportions of water. The proportion of water used in the production process is defined as virtual water contained in the product. (Hoekstra, 2003). According to the estimates, more than 3 billion people will be confronted with water shortage in 2025. All these problems have revealed the necessity of taking political, economic and ecological measures and sustainable practices. To reach sustainable development goals, education plays a major role (UNESCO, 2002). There is a need for education regarding sustainable water consumption. Regarding Education for Sustainable Development, the ongoing water use needs to be discussed in the classrooms.

Due to the model of educational reconstruction (Duit, Gropengießer, Kattmann, Komorek, & Parchmann, 2012) the investigation of student pre-conceptions is crucial to address when designing education for achieving conceptual understanding. Complex socio-scientific concepts are not easy to address in education in way, enabling students to apply the concepts in their everyday life for making decisions about a sustainable life-style. So far, little is known in the research literature on student´s conceptions about complex socio-scientific concepts, like the water scarcity and virtual water flow topic.

Therefore, the aim of this study is to analyse high-school students’ conceptions of sustainable water use and water scarcity issues. In order to enable educational reconstruction, conceptions about sustainable development and virtual water have been surveyed.

The study was conducted in 2018 with 159 high school students from Turkey. This sample was chosen in analogy to study in Germany with 102 students. The German study is already published (Benninghaus et al., 2018) and was conducted two years earlier. The questionnaire was identical with the German language instrument. It was translated by the bilingual co-researcher of this study from German into Turkish. The instrument contains five items with various task formats. Open task formats were used in three items (concepts of sustainability, virtual water and water-intensive products). Responses were evaluated using the qualitative content analysis technique presented by Mayring (2014). The coding guideline was adapted from the study of Benninghaus et al. (2018). There generalized statements based on sample quotations are already elaborated; the guideline was then used to categorize student responses. The other items have a semi-open task format and were quantified by tallying. The detailed questionnaire is published in Benninghaus et al. 2018. In the following we give some item examples. Conceptions associated with sustainable development: This Item asked using an open question: “What does ‘sustainable development’ mean to you? Give a brief answer.” For the evaluation, statements were transcribed from written to digital and inductive category formation was performed using the method described by Mayring (2014). Conceptions associated with virtual water: This Item asked using the question: “What does the term ‘virtual water’ mean to you? Give a brief answer.” According to Fremerey, Liefländer, & Bogner 2014 one cannot expect far-reaching concepts, if any at all. The establishment of categories was therefore performed inductively as well so any statement could be categorized. Conceptions associated with spatial aspects: Items based on blank maps were implemented for spatially-oriented research questions. These depicted only national boundaries. One of this items (Countries with Water Scarcity) contained a brief introductory text followed by task instructions. Students were to circle those countries on a map they thought currently suffered from water scarcity. Other item (Countries with Water intensive Production) was structured analogously. Evaluation involved tallying the countries that were clearly marked. Conceptions associated with water-intensive products: This item was intended to assess students’ knowledge of water-intensive products. Students were asked to list up to ten products they considered to be water-intensive. Evaluation was performed inductively to facilitate assignment of the products stated to defined product categories on the basis of frequency.

According to survey results, most participants both from Germany and Turkey associated the concept of sustainability with the principle of “intergenerational equity”. Intragenerational equity was referred to less frequently, however a regional context was established in such cases by German students. None of the Turkish students emphasized the principle of “intergenerational equity”. When students’ concepts were examined in terms of three dimensions of the concept of sustainability, it was observed that ecological dimension was prevalent for both student groups. Survey questions on the conceptions of sustainable development generally reveal that both German and Turkish students have a strong focus on ecological and intergenerational equity aspects. These results are also parallel to some other researches that conducted with different study groups. (Birdsall, 2014; Summers & Childs, 2007; Summers, Childs, & Corney, 2005). In the context of the conceptions relating to virtual water it is evident that a large majority of survey participants from Germany did not answer the question. On the other hand, the ones who answered the question regarded production as the step of the production chain which is most relevant to the consumption of virtual water. Almost all Turkish participants indicated that they had never heard the concept of virtual water before. Among answers given to the question of which parts of the world there is water scarcity, African continent dominates these answers from both groups. According to student opinions, other regions are not often associated with water shortages. It was observed that students had a narrow perspective that did not overlap with the facts in this item. Other results obtained from the research and the contribution of these results to the education process and the recommendations for classroom instruction will be presented and discussed during the presentation.

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