Good practices

Nitrite Water Analysis: a practical approach to dye synthesis
Working Group:Science through digital learning, Low Achievers in ScienceCountry:GermanyLanguages:English, GermanAge of students (target group/s):15-18
The project described here is embedded in the frame of a regular school lesson conducted in senior classes in high school. To address issues of the chemical field of dye synthesis and especially the azo dye substances, this lessons setup starts with a problem definition. This is done by introducing the problem using a question posed in an internet forum expressing the problems of fish dying in a fish tank. By reading and discussing this question, a definition of the problem is formulated and thus, the first step of inquiry based learning is completed. The teacher then provides a chemical analysis of the water in the fish tank in which all fish have died. This focuses the students’ attention on the most important facts of the problem. Planning and introducing the issue with this method results in a problem oriented perspective of the class and leads the students in the right direction to address the problem with a suitable approach. After this introduction, the class is divided into three groups with each group dealing with a different aspect of the problem (Method: Group puzzle). To fully understand the problem and to underline the results, the students plan and conduct a water analysis focusing on nitrite. The results of each group are finally combined to generate a solution to the problem with respect to a) the chemical mechanisms (azo dye synthesis), b) the experiments conducted (evaluating the results and possible sources of errors) and c) the biological aspects (nitrogen cycle). The solution developed at the end of the lesson is given to the “owner of the fish tank” by replying in the internet forum. The reply provided in the internet forum not only gives a suitable and traceable solution to the problem, but additionally a specific focus is given on precisely formulating the problem statement, the approach for the solution of the problem and the results with special emphasis on the use of the correct terminology. Thus, by using a format (internet forum) and problem which is meaningful, intuitive and close to the students’ communication habits, the basics of scientific writing skills are developed.Strong points and opportunities:Dye synthesis is a very complex topic in senior classes. Almost every azo dye is toxic. Thus teachers can usually not use them in class. The nitrite water analysis is one of very few opportunities to experiment with an azo dye in schools, thus connecting theory to practical application and experiment.
The focus of the approach is on the students’ perspective in a) determining the problem, b) developing relevant questions and c) establishing a method and schedule to solve the problem. This approach is perceived by the students as being very satisfying. It gives them great confidence in what they have learned so far and how to use their knowledge. They learn how to approach a problem and how to work as a group to solve it. This student oriented method enables the students to understand the mechanisms of dye synthesis more easily than using a teacher oriented approach.
Another advantage of this approach is that all students get a result at the end of the lesson. This lesson is clearly structured with a motivational introduction posing a real world problem, the development of an approach to solve the problem and a clear conclusion with regards to the problem solution and documentation. Thus the format of this approach leads to a stronger engagement of the students, since they are more integrated into the topic of the lesson. They play a role in the development of the solution and in the documentation of the results.Limitations:There is a possibility of failure, since the topic of this lesson is complex and relates to more advanced levels in high school. Depending on the prior knowledge of the students the teacher may have to alter the schedule of this lesson with respect to the theory of the dye synthesis, possibly enhancing the practical parts.Added value with regards to the 3 topics of the MASS project:The nitrite water analysis lesson has a strong focus on inquiry based learning. The students develop a definition of a problem and then a plan how to solve it. By doing so, they combine chemical theory and concepts with practical aspects such as the water analysis. Despite the inherent complexity of the topic, the combination of theory and experiments is suitable for low achievers in the class, since every student can contribute to the success of the project and to the solution of the problem. With regards to the technical equipment used in this lesson, all students have to use the internet and a laptop to extract the main problem and to document the solution. This blended learning approach integrates inquiry based learning using experiments, group learning and the use of internet technology for motivation and documentation or the problem.