Abstrakt
Chemical reactions belong to the most important thematic units in chemistry at primary school. In the chemistry curriculum, it is also a key point and critical point. Our aim was this subject matters to approach to pupils. In order to, we have proposed to include the experimental calcium cycle, which can show to pupils in the teaching the different types of reactions through the mediation of the monothematic set of experiments. This consists from the following reactions:
1) thermal decomposition of calcium carbonate,
2) reaction of calcium oxide with water,
3) reaction of calcium hydroxide with hydrochloric acid,
4) reaction of calcium chloride with sodium carbonate. The starting material of the cycle is calcium carbonate, which is also the final product of the cycle. The individual steps of the cycle were completed by a series of simple tests (pH changes, cation and anion evidence, etc.). In this case, an action research was realised by collaborating teachers in four classes at three primary schools. The results of the action research showed that the experimental cycle of calcium was accepted favourable by the pupils. However, some phases of the cycle were difficult to implement in school conditions. This is the first step of the cycle - thermal decomposition of calcium carbonate, which requires the use of the efficient burners. Experience with the experimental calcium cycle are favourable. The modification of the first step of the cycle is ready, will be verified in teaching of chemistry at primary school.