We realize importance of summative assessment of science process skills. There has been ongoing national
project of external online testing for all educational areas, including science education in Slovakia. In this study
students fail the tasks related to design experiment. Also Harlen (2006) consider the skill to design experiment
(including state hypothesizes) as one of the most important but also as one of the most challenging.
Demkanin (2012) points to necessity to discuss with teachers the benefits of students design experiments,
because they consider this time not effectively spent. We described the activity which consists of taking few test
tasks and related experiment to verify answers. We consider it very useful for development of science process skills,
especially hypothesizing, controlling variables, planning experiment. We observe these benefits of taking test tasks
first. For student – it helps him to determine what is important, suggest him some scheme, he can follow on his own
experiment (analogy) and it is way how he realise what he does not know, what he needs to improve. For teacher is
first evidence of level of student´s performance –for what to aim to and discuss with them. Related experiment
eliminates deficiencies of test tasks – if fail only for other cognitive skills (writing skills).We observed that this
activity engaged students to design their own experiment to investigate something. Indeed we can mark it as
formative assessment and we realise that there is a lot to research.