This research investigates the effect of classroom explicitation of initial conceptions (CEIC) on conceptual change in the context of learning electricity. Eight hundred and seventy five thirteen year-olds were tested in laboratory conditions to see if CEIC is or is not a productive step toward conceptual change. All students experienced a problem-based pedagogical treatment called "the electronic challenge." The randomly determined experimental group was also exposed to CEIC. Data shows a significant beneficial effect of CEIC and no unwanted "contamination effect," particularly for female subjects.