Introduction: School context is very rich with different and intensive emotional experiences (Pekrun, 2016). Regardless, more systematic research of academic emotions had only begun in 1990s (Schutz & Lanehart, 2002). Academic emotions are emotions related to academic learning, classroom instructions and academic success (Pekrun et al., 2002). There are four different categories of those emotions: achievement, epistemic, social and thematic emotions that differ according to their object focus. In addition, those emotions can be differed upon their valence (positive or negative) and activation (activating or deactivating). In this thesis, we were focused mainly on epistemic emotions, which result from cognitive qualities of task information and the processing of that information (Pekrun & Stephens, 2012). Another definition is more specific and defines epistemic emotions as emotions that result from information-oriented appraisals about the alignment or misalignment between new information and prior knowledge structure, recently processed information or existing beliefs (Muis et al., 2018). The most common epistemic emotions are surprise, curiosity, confusion, anxiety, enjoyment, frustration, and boredom, which were also assessed in this thesis (Pekrun et al., 2016). Earlier research on academic emotions showed that they are subject-specific and should be examined in that way (e.g., Goetz et al., 2006). In this thesis, epistemic emotions were assessed in the context of physics. Also, all previous research examined epistemic emotions related to some specific task that participant had to work on (e.g., Trevors et al., 2017), while in this research we assessed them as a trait, i.e. as a typical emotional experience in the context of learning new content at physics class. Also, taking into account the dimensions of valence and activation, enjoyment and curiosity were defined as positive activating emotions, anxiety, frustration and confusion as negative activating emotions, boredom as a negative deactivating emotion, while surprise was defined as a neutral activating emotion (Muis, Pekrun et al., 2015; Muis, Sinatra et al., 2018). The control-value theory of achievement emotions was used as a theoretical framework for investigating the determinats and effects of epistemic emotions (Pekrun, 2006). The theory defines different contextual and individual antecedents of academic emotions and their effects on cognitive and motivational outcomes and academic achievement. Regarding control-value theory of achievement emotions, students’ cognitive control and value appraisals are proximal determinants of academic emotions (Pekrun & Perry, 2014). The perceived control is defined as appraisal of control over activities and outcomes, but also as the subjective likelihood to obtain those outcomes. The perceived value is also related to the activities and outcomes and it can be extrinsic or intrinsic. All other antecedents proposed by the control-value theory are distal and affect academic emotions only indirectly, via cognitive control and value appraisals. In this thesis, teaching quality was assessed as the contextual antecedent of epistemic emotions. Teaching quality is a degree in which teachers manage to create appropriate structures that allow students to begin and maintain insightful learning processes (Kunter & Voss, 2013). It has three dimensions: (1) classroom management, (2) cognitive activation and (3) student support (Klieme et al., 2009). Regarding outcomes of academic emotions, the theory assumes that emotions have indirect effect on students’ achievement via different motivational and cognitive aspects of learning. In this thesis, we examined indirect effect of epistemic emotions on achievement in physics via engagement in learning physics as motivational outcome. Engagement is a multidimensional construct, sometimes defined as a “meta” construct that consists of cognitive, behavioral and emotional engagement (Fredricks et al., 2004). Cognitive engagement implies students’ willingness to invest effort in understanding complex ideas and master difficult skills, behavioral engagement includes involvement in different academic activities, while emotional engagement includes positive and negative reactions to teacher, classmates, academics and school (Fredricks et al., 2004). There is scarce number of published research about the relationship of those antecedents and outcomes of epistemic emotions and huge gap in the literature. Because of that, the aim of this doctoral thesis was to test the assumptions of the control-value theory of achievement emotions in the explanation of the determinants and outcomes of epistemic emotions in the context of the subject of physics. Research questions and problems Research questions in qualitative research 1. In which situations students experience discrete epistemic emotions in the context of the subject of physics? 2. What are the frequencies of experiencing discrete epistemic emotions in the context of the subject of physics from the students’ perspective? 3. What is the relationship between discrete epistemic emotions and motivation for studying physics from the students’ perspective? Research problem in the pilot study 1. Examine the psychometric properties of the measure instruments that will be used in the main research. Research problems in the main research 1. Examine the mediation role of cognitive appraisals in the explanation of the relationship between teaching quality and epistemic emotions in the context of the subject of physics. 2. Examine the mediation role of engagement in the explanation of the relationship between epistemic emotions and achievement in the context of the subject of physics. Qualitative research: Methods: Participants: In this study participated convenience sample of the 8th grade students (N = 31, Mage = 13.68) from two elementary schools from Zagreb. Students had very good mean grade point average (GPA) from physics at the end of the 7th grade, while the mean overall GPA was excellent. Instruments: Students were asked questions about their general opinion regarding the subject of physics, different situations while learning at class or at home at which they experience emotions, situations in which they experience discrete epistemic emotions, their perception about the cause of each discrete epistemic emotion and the effects of those emotions on motivation for learning physics. Beside this, students had to fill out the questionnaire about their gender, age, GPA from physics and overall GPA at the end of the 7th grade. Procedure: In total, six focus groups were conducted with four to seven participants in each group. The focus groups were moderated by the author of this thesis and were all conducted in the schools from which students were. Students and their parents gave their written consent for the participation in the study. All focus groups were audio recorded and lasted around one hour. Data analysis: All audio records were transcribed and qualitatively analyzed according to the guidelines for thematic analysis from Braun and Clarke (2006). Results and discussion: In order to answer the first research question we analyzed the data to find out the situations in which students experience seven discrete epistemic emotions (surprise, curiosity, enjoyment, anxiety, confusion, frustration and boredom) in the context of physics. The results showed that the number of situations varied from two situations for anxiety to eight different situations for enjoyment and confusion. Students experienced different epistemic emotions in the same situations (e.g., surprise, curiosity and confusion when they gave wrong answer to the question), while in some situations they experienced only one specific epistemic emotion (e.g., enjoyment while working in a group). Regarding second research question, the results showed that students perceive that they most and least frequently experience curiosity, enjoyment, confusion and boredom. Anxiety was the emotion that they mentioned only in the category of the most frequently experienced emotions, while frustration was only mentioned in the category of the least frequently experienced emotions. Students did not mention surprise in any of these two categories. Furthermore, the results showed that curiosity, enjoyment and surprise were emotions that motivate them, while boredom and frustration were emotions that do not motivate them for learning physics. For confusion, some students perceive that it motivates them, while some students perceive that it doesn't motivate them for learning physics. Pilot study Methods Participants In total, 431 7th grade students (Mage = 12.75) from twelve schools from the city of Zagreb and Zagreb County participated in the study. Students had very good overall GPA. Instruments: In this study, we assessed epistemic emotions, cognitive control and value appraisals, engagement in learning physics, physics teachers' teaching quality, school achievement in physics, sociodemographic data and previous school achievement. Procedure: The research was conducted in one time point during November and December 2019. Students and their parents gave their written consent for the participation in the study. Students filled out the questionnaire during regular school classes and the whole procedure lasted for about 45 minutes. Data analysis In order to test psychometric properties of measure instruments, we analyzed descriptive statistics, manifest correlations, reliability and conducted confirmatory factor analysis (CFA) of those instruments. Results and discussion The results showed that majority of measure instruments had adequate psychometric characteristics, while those that did not, were revised for the main research. CFA of the Epistemically-Related Emotion Scales, which were used to assess epistemic emotions did not fit well to the data and students often asked for explanation for some of the terms used in this scale. Therefore, we changed the translation of those terms for the main research. The Monitoring Scale also did not have adequate psychometric properties and it was replaced with other, more often used scale. Five items from Engagement in Physics Scale were removed in order to achieve good fit to the data, but we decided to include the original version of the scale to test its structure once more. At the end, we decided to assess the achievement in physics by three separate categories of grades in physics in order to have the possibility to create a latent variable. All other measures were included in original version. Main research: Methods: Participants: In this study participated 545 8th grade students (Mage = 13.99) from twelve elementary schools from the city of Zagreb and Zagreb County. The students had very good GPA in physics and overall GPA at the end of the 7th grade. Instruments In this study, original and/or revised versions of measure instruments that were used in the pilot study were included. We assessed epistemic emotions, cognitive control and value appraisals, engagement in learning physics, physics teachers' teaching quality, school achievement in physics, sociodemographic data, previous school achievement and information regarding the physics teacher – whether the students had the same teacher in the 7th and 8th grade. Procedure: The research was conducted in one time point during February 2020. The procedure was the same as in the pilot study. Data analysis: We analyzed descriptive statistics, manifest correlations and conducted CFA and structural equation modelling. Results and discussion: The results showed that cognitive control and value appraisals were mediators in the relationship between teaching quality and epistemic emotions. The value appraisal was a significant mediator in the relationship between students’ perceptions of their physics teacher monitoring and support and all epistemic emotions. Higher students’ perception of monitoring and support from their teacher predicted higher value that students had for learning physics, which in turn predicted more intense surprise, curiosity and enjoyment and less intense boredom and negative activating emotions. Besides this, higher perception of monitoring was also direct predictor of higher curiosity and enjoyment and less intensive boredom, while higher perception of teacher support directly predicted less intensive negative activating emotions. The control appraisal was significant mediator only in the relationship between teacher support and curiosity and negative activating emotions. Specifically, higher perception of support predicted higher self-efficacy among students, which in turn predicted higher curiosity and lower intensity of negative activating emotions. Regarding the second research question, results showed that engagement in physics mediated relationship between epistemic emotions and achievement in physics. Specifically, the only significant mediator was cognitive engagement in the relationship between curiosity and achievement. Higher curiosity predicted directly and indirectly, via higher cognitive engagement, higher achievement in physics. Conclusion: Results of these three studies pointed out to the importance of the epistemic emotions for students learning and achievement in physics. Contextual determinants, namely teaching quality, directly and indirectly, via cognitive control and value appraisals, predicted epistemic emotions. On the other hand, only epistemic curiosity directly and indirectly, via cognitive engagement, predicted achievement in physics. These results were in line with some of the assumptions from the control-value theory of achievement emotions, but there are many other determinants and outcomes of these emotions that still need to be examined in order to gain more knowledge about this highly important topic in academic context.