The rate of success in the first trial with the real circuit was low in all groups (less than 15%). From this point on, the difference between the groups became very evident; in the control group the real trial was the first source of feedback. Some of the teams changed their design (on the worksheets) while others, tried changing the real circuit. During this process (that took up to six trials) 5 more teams (17%) managed to correct their design so that by the end of the session 15 teams (52%) arrived at a correct theoretical design, but only 11 of them (38%) managed to implement the solution in a real circuit. The main problem encountered by the control group teams was to work out what was wrong: the design or the way they have connected the real circuit. Since there was no other source of feedback, some of the teams changed a correct design, ‘falling back’ into a misconception they seemed to have resolved in an earlier stage. A typical example is presented in Fig. 5 in which the initial design reflects a common misconception: students did not realise that there is no difference between A and B. The real circuit was built as designed and the bulbs lit accordingly. The team identified the problem, corrected the design and was ‘completely sure’ that it will work. Then, in the course of changing the real circuit, a short was connected across three of the bulbs and as a result only bulb A lit. The team was confused, apparently not completely sure of the design and changed it again ‘falling back’ into the original misconception.