This paper presents changes in how two teachers described their intentions, and then enacted, a science lesson, one lesson about acids and bases and one about connecting a diode into a complex circuit before and after their participation in learning studies. Before the learning studies , the intended object of learning (described in the interview before the lesson) did not correspond clearly to the object of learning that then was manifested in the lesson. Even if the expected learning difficulties of the students were well known to the teachers (the molecular level and the relationship between H+ , OH- and H2O) and how to connect the diode the right way)these difficulties were not focused in the lesson before LS. The lessons after the learning studies focused hat was seen as difficult for the students and the critical aspects was pointed out by conscious usage of variation theory. By simultaneous treatment of concepts and examples contrasts were created. For example, in the lesson about acids and bases the three concepts acidic, basic and neutral were dealt with at the same time, both on a macroscopic level (with experiments) as well as on a molecular level (by explaining the relationship between the ions and the water molecule.). The lessons before LS had focused the experiments with acids and their colors with different indicators while bases and the ions involved were hardly touched upon. In the lesson about the diode, both right and wrong ways of connecting the diode into complex circuits were demonstrated in the lesson after LS, something that was not the case in the lesson before LS. In this way the object of learning was more defined and focused, the critical aspects made possible to discern and the enacted object of learning more in line with what was intended.