Traditional chemistry experiment teaching often follows a linear and programmed narrative approach, with students mechanically repeating the experimental process, which is extremely detrimental to the career and cognitive development of chemistry education students. This study explores measures to bridge the gap between theory and practice by reconstructing the classic preparation experiment of ferrous ammonium sulfate (Morel salt) through micro-engineering zoning. This teaching reform is aimed at the freshmen of the 2024 freshman chemistry teacher training program in the second semester, who are transitioning from passive exam-oriented learning to professional teaching thinking and have received another semester of basic experimental training. By implementing the micro engineering teaching reform of the “six zone cognitive scaffold matrix”, we have replaced the standard linear operation instruction with an interlocking reasoning framework. The reform involved 90 students majoring in chemistry education, and the results showed that the experimental group using cognitive scaffolds performed well in explaining complex chemical mechanisms, such as the thermodynamic stability of products and the kinetic mechanisms preventing oxidation, while maintaining basic experimental skills. The systematic training of students through this method not only enhances their proficiency in experimental operations, but also cultivates the necessary “subject teaching knowledge” (PCK) for future educators.