Authors: Gergely Levente Szabo, Andras S. Szabo, Margit Izsak, Janos Bozi, Eszter Imola Tisza-Kosa

Keywords: acidity, analysis, physical properties, measurement technique, viscosity

1. Summary 
Experiments have a dominant role in the education of natural science subjects. It has been our experience that students have been very satisfied, if the materials used in the experiments were well known substances to them, in this case foodstuffs. Again, 10 simple experiments of physical, chemical and biological type are described, concerning the following topics: measurement of the temperature of black coffee and milk exposed to natural light, study of capillarity in a sugar cube dipped into coffee or red wine, measuring honey viscosity, determination of the acid content of vinegar, the change of cooking oil viscosity as a function of temperature, measurement of concentration on the basis of the law of Archimedes, acidity measurement of fruits, measurement of the alcohol content of alcoholic beverages, microscopic examination of yeast, study alcoholic fermentation produced by yeast. Foodstuffs used during the investigations and measurements: apples, black coffee, brandy, fruit juice, honey, milk, oranges, red wine, rum, sucrose, sunflower oil, vinegar, wine, yeast.

2. Introduction 
As it was mentioned in our earlier papers [1], [2], [3], [4], the presentation of experiments has a dominant role in the education of natural sciences. If the experiments are part of the teaching materials, the education will be hopefully more successful and effective. In the previous articles, 10 experiments each were described, some of them belonging to the field of physics, the others were of the chemical or biological type. Of course there is no sharp boundary between these disciplines, and the presentation of the overlappings and relationships – chemistry is based on physics, and biology is based on chemistry – and the stressing of the interconnections play an important role in the modern education of natural sciences. In this final part of the series, again 10 simple experiments are described, related to food investigations. These measurements can be performed without difficulties in the average school laboratory equipped for physical, chemical and biological tests.