Educational webcasts are nowadays widely used by many organizations and institutions all over the world. However, the educational effectiveness of webcasts when used as an autonomous method is yet to be explored. In this paper, the clarification of certain issues concerning their educational effectiveness is attempted. Following specific instructions, an educational webcast was developed, and then a between group evaluation experiment was conducted. The experiment compared traditional learning and an educational webcast. A total of 66 gymnasium (middle school) students were placed in two groups based on a pretest method. The results of the evaluation showed that educational webcasts can be very effective on certain conditions. On the one hand, the educational effectiveness of the webcast was particularly high when applied to tasks that required simple comprehension. On the other hand, the webcast had poor performance in the consolidation of complex tasks. (Contains 1 figure.)