TY - JOUR T1 - Primárne energetické zdroje a efektívnosť varenia A1 - Velmovská, Klára JA - Obzory matematiky, fyziky a informatiky Y1 - 2009 VL - 38 IS - 2 SP - 47 EP - 59 SN - 1335-4981 N2 - The on-going reform of education requires students and teachers to develop the key competencies. This article shows one of the possible activities aimed at developing competencies in solving problems related to energy. Energy prices are increasing what stresses the question, how to maximize savings. The statement, that the cheapest energy is the one saved, is still true, because it needn't be produced, transported, transformed, mined, imported and processed. In this paper, the closer look at the primary energy resources and energy saving options for cooking in the household is taken. We deal with the efficiency of cooking. Efficiency of heat transferred to the water in a pot is found out experimentally, depending on the material from which the pot was made, on the area of pot's bottom. The result of experiment depends also on the fact whether the cooker has been covered. We compare the efficiency of three appliances: gas cooker, electric cooker and electric kettle. ER -