Nowadays, the use of information technology (ICT) in education is nothing new. But the question is where the limit is when the use of ICT does not have the desired effect. In the paper we discuss the use of simulations in the teaching process that can positively influence students' achievements. At the beginning of the paper we present the results of a research aimed at exploring the impact of the use of computer simulations on secondary school students' understanding of oscillatory motion. The aim of the research was to explore the effect of the use of simulations on students' abilities to work with graphs and to find out relevant information. In the conclusion, the possibilities of integration of simulations into the teaching process are discussed.