The present research investigates the contribution of an interactive educational virtual environment on milk pasteurization to the learning outcomes of 40 students in a technical secondary school using SOLO taxonomy. After the interaction with the virtual environment the majority of the students moved to higher hierarchical levels of understanding on the structure and operation of the pasteurization apparatus, the different paths and temperatures of fresh and pasteurized milk, hot and cold water, and the way heat is exchanged. The functional nature knowledge the students constructed, led them to develop physical nature knowledge, knowledge of the relationship between physical and functional nature, and finally process knowledge. The design of the three dimensional virtual environment, its content and the meaningful learning tasks are important for technology knowledge. (Contains 1 table and 7 figures.)