Abstract Aiming at the unbalanced teaching effectiveness in traditional basic synthetic experiments caused by individual differences among students,a teaching plan is designed based on constructivism and the Zone of Proximal Development theory to balance students' fundamental learning and individual needs.Taking the potassium alum preparation experiment as the foundation,it is expanded to include a popular science-oriented optional mordanting experiment using potassium alum as a mordant and natural purple cabbage dye on cotton fabric under different pH conditions,where the preparation part is compulsory and the mordanting part is optional.The experimental content integrates traditional preparation with natural dye mordanting applications,and the teaching mode“focusing on basics+emphasizing individuality”caters to the developmental needs of different students,especially fitting the cognitive characteristics of lower-grade learners.By providing autonomous exploration space and stimulating chemical learning interests and scientific exploration awareness through open-variable design,this study offers a new paradigm for basic experimental teaching.
