The purpose of this study is to provide reliable evidence of the observable correlates of the Aha! moment and what this means for moving from surface to deep thinking. The study analyses facial expressions and body language from video recordings of students solving problems, followed by interviews, focus groups, and surveys. The problem-solving involved asking students to solve word problems to generate an Aha! moment and seeing how their expressions changed (or not) when they ascertained the correct answer. Findings showed clear facial, emotional, and body language changes when the problems were solved. Implications for teaching are discussed.