The aim of the present research was to compare two methodological tools with two groups of pre-university secondary education students (17-18 years old). The experimental group worked constructing concept maps using the jigsaw technique (experimental teaching approach, ETA) on the topic of radioactivity in five sessions of their physics course. The control group worked on the same subject in a traditional teaching method (lecture-based teaching approach, LTA). The research design was quasi-experimental, with 28 students of a school in Extremadura (Spain). The results of a pre-test and a post-test were compared for the two groups. The working hypotheses were: (a) students who work collaboratively in constructing concept maps using the jigsaw technique perform better in learning the topic of radioactivity; and (b) this method fosters a positive attitude of the students towards how the topic is taught. With respect to Hypothesis (a), the results appeared to show an improvement in learning in the experimental group, although without reaching statistical significance. Neither were there any statistically significant differences between the post-test results of the two groups. With respect to Hypothesis (b), most of the experimental group students found the method to be very encouraging; despite the insecurity they felt with something new that they were not used to. The experimental group's pre-test and post-test results were strongly correlated (r=0.707), so that the ETA can be regarded as fairly effective since the students learnt more meaningfully and with less effort.