A HANDS-ON ACTIVITY TO PROMOTE CONCEPTUAL CHANGE ABOUT MIXTURES AND CHEMICAL COMPOUNDS

The study revealed students' conceptions about mixtures and chemical compounds and also investigated the effects of a hands-on activity designed to improve their understanding of differences between two concepts. The sample consists of 52 seventh grade students in a primary school. Students' ideas were elicited by a test consisting of six open-ended questions. An intervention designed based on students' preconceptions. The intervention, in which two different colored balls of clay were used, comprises a hands-on activity whose aim was to help students distinguish essential differences between mixtures and chemical compounds. After the intervention, the test was re-administered to the sample as a post-test. Both qualitative and quantitative assessment indicated positive effects of the intervention on students' understanding. The results suggest that teachers and curriculum developers should take into account this kind of activities in order to help students understand confusing concepts.