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纸张是学生最为常见的学习用品之一,这里的纸上实验并非是在纸上做化学实验题,而是要借用纸张,利用其成分进行一些化学趣味实验,在进一步了解纸张成分及其化学性质的同时培养学生的创新思维,让学生感受化学知识的无穷魅力。现介绍4组实验与同行切磋交流。一、反复变色,乐此不疲1.实验原理纸张的主要成分是纤维素,纤维素浸水后遇到碘是不会变色的,但普通打印纸或用于书写的纸张通常会涂上一层淀粉浆,淀粉浆遇碘颜色会发生变化,即淀粉液遇到碘水或碘酒
Paper is one of the most common school supplies for students. The paper experiment here is not a chemical experiment on paper. Instead, it borrows from paper and uses its ingredients to perform some chemical taste experiments. With further understanding of paper composition and its chemical properties While cultivating students’ innovative thinking, let students feel the infinite charm of chemical knowledge. Now introduce 4 groups of experiments and peer exchange of ideas. First, the repeated discoloration, bored 1. Experimental principle The main component of paper is cellulose, cellulose immersion encounter iodine is not discolored, but ordinary paper or paper for writing is usually coated with a layer of starch slurry, Starch slurry will change the color of iodine, that is, starch solution encountered iodine or iodine