Modern physics has an important role in the high school physics curriculum in Croatia with many topics from quantum and nuclear physics, and special theory of relativity. This physics content is present at the high school level more than in most of European countries. The diploma thesis is focused on introduction to quantum physics. Physics education research has shown that both pupils and students have difficulties with the ideas in quantum physics. The research has shown that interactive teaching is very effective in developing a conceptual understanding of modern physics. Experiments can be very useful for involving students in the discussion and active learning. Unfortunately, modern physics is taught in traditional way in Croatian schools. The aim of this diploma thesis was to develop interactive teaching materials that could be directly used in the classroom. Due to the nature of quantum physics and poor equipment in schools, not many of modern physics experiments can be done in the classroom. However, some relatively simple and available experiments should be performed. In addition, interactive computer simulations can be used as some form of the experiment in enquiry-based teaching and learning. Simulations help in visual representations of abstract concepts and microscopic processes that cannot be directly observed. The thesis contains lesson plans with experiments and interactive simulations for introducing blackbody radiation, photoelectric effect, spectra and models of atoms. Some teaching materials have been tested in school, and this experience is described.