Traditional teaching does not often allow very active involvement of pupils in class. In chemistry and natural sciences in general experimental and laboratory work is one of the most effective methods for acquiring knowledge. Experimental work can also be exercised using virtual world. Virtual laboratory offers some important advantages. Understanding chemistry involves the ability of cognitive comprehension on three levels: the macroscopic level, the symbolic level and the level of particles where the virtual laboratory can be an effective tool. On this basis a didactic experiment was performed in order to verify the effectiveness of virtual laboratory from pupils' knowledge point of view. The experiment involved seventh grade pupils (N = 38). Furthermore, we tried to answer the question whether the learning results of pupils, according to the experimental design of classes using a virtual laboratory, are better than results gained through teaching classical science classes without visualization tools. The research of the didactic experiment carried out on a relatively small, pilot sample of pupils has shown that acquiring knowledge is more effective when using the virtual laboratory instead of classical teaching (in the case when classical approach does not include visualization elements crucial for learning and understanding chemistry).Nataša Rizman Herga is a teacher of chemistry and biology in Primary school Ormož. As a postgraduate student of Educational Sciences she conducts researches and publishes in the area of teaching science and e-learning.Dejan Dinevski is an associate professor at the Faculty of Education and Faculty of Medicine, University of Maribor. He coordinated several international and national projects in the the wider area of e-learning. He is an author of several publications on e-learning, including scientific articles and books.

Understanding chemistry includes the ability to think on three levels: the macroscopic level, the symbolic level, and the level of particles -sub-microscopic level. Pupils have the most difficulty when trying to understand the sub-microscopic level because it is outside their range of experience. A virtual laboratory enables a simultaneous demonstration of all three levels of a chemical concept along with dynamic visualisation at the submicroscopic level. This study presents the effective usage of a virtual laboratory that can overcome the gap between the previously-mentioned conceptual levels. We carried out a didactic experiment to test the effectiveness of a virtual laboratory that enables dynamic visualisation. The experiment involved seventh-grade pupils (N = 109) from five different primary schools in Slovenia. We asked ourselves the question as to whether the learning outcomes of pupils are better when they use a virtual laboratory rather than in science classes without a virtual laboratory where dynamic visualisation at the submicroscopic and sub-micro levels are only explained by means of static demonstrations. A virtual laboratory has many significant advantages. The results of the didactic experiment showed that, in terms of knowledge acquisition, using a virtual laboratory is better than science classes without visualisation elements.representations are essential for understanding several chemistry concepts and phenomena. Studies indicate that students experience difficulty in understanding the sub-microscopic system of representations because these representations are abstract and cannot be experienced. These problems can be overcome with the use of a virtual laboratory that integrates all three levels of representations. This article deals with a study about a didactic experiment from the pupils' points of view after using a virtual laboratory.

Učenje in poučevanje kemije je zahteven proces, saj vključuje abstraktne pojme in koncepte, ki se jih pogosto ne da videti ne dotakniti. Uporaba sodobnih informacijskih tehnologij ponuja pomoč pri premagovanju tovrstnih težav, saj nam omogoča vizualizacijo naravoslovnih pojavov, ki so premajhni, prehitri, abstraktni ali ogromni, da bi jih neposredno opazovali. Številne raziskave kažejo, da uporaba vizualizacijskih gradiv (od fizičnih modelov, analogij, animacij, simulacij, submikropredstavitev, virtualnih okolij) izboljša razumevanje kemijskih pojmov. Vizualizacija abstraktnih pojmov in varno okolje za eksperimentiranje sta le dva razloga, ki kažeta v prid uporabe informacijsko-komunikacijske tehnologije (IKT) pri pouku kemije. Želeli smo raziskati, ali jo slovenski učitelji vključujejo pri učenju in poučevanju kemije in kako pogosto so posamezna gradiva za vizualizacijo vključena. Cilj tega prispevka je analiza uporabe vizualizacijskih elementov, ki jih omogoča IKT, pri pouku kemije med slovenskimi osnovnošolskimi učitelji.

In natural science education it is important that the macroscopic, submicroscopic and symbolic levels are interconnected in a student’s mind. Primary school children have the greatest difficulty in understanding the sub-microscopic, which is outside their experiential framework. This research examines the classroom application of the virtual laboratory in integrating macroscopic, submicroscopic and symbolic aspects of chemistry. Pupils of the seventh grade, aged between 12 and 13 years (N = 225), participated in the didactic experiment that was conducted in ten primary schools in Slovenia. The fundamental research question was whether pupils studying the same natural science content using the virtual laboratory performed better than those who did not. The results of the experiment revealed that in terms of knowledge acquisition the use of a virtual laboratory improved pupil performance in relation to those who did not use elements of dynamic visualisation in the classroom. In accordance with Bloom’s cognitive scale, it was demonstrated that in relation to basic, higher and advanced levels of knowledge and comprehension, the use of the virtual laboratory positively influences pupils’ understanding of selected concepts in chemistry. Key words: virtual laboratory, dynamic visualization, chemical concepts, submicroscopic level.