选择硝酸铅和铬酸钾作为相互扩散的反应物以形成铬酸铅在琼脂凝胶中的周期性沉淀．分别在光照和黑暗中对六种不同浓度的硝酸铅溶液进行了实验．根据实验现象对周期性沉淀的形成提出了可能的机理．认为光辐射可使铬酸铅部分电离，从而减慢了胶核成长速率，有利于汇聚成带． Lead nitrate and potassium chromate were selected as interdiffusion reactants to form a periodic precipitate of lead chromate in an agar gel. Six different concentrations of lead nitrate solution were tested in the light and the dark, respectively. Based on the experimental phenomena, a possible mechanism for the formation of periodic precipitation is proposed. It is considered that the light radiation can ionize part of lead chromate, thereby slowing the growth rate of the gel nuclei and facilitating the aggregation into a band.