现行高中化学课本所演示的有关胶体性质的实验,除了“丁达尔现象”外,按课本操作电泳和渗析都不明显,且需要时间较长,学生看不清楚,现我们把电泳和渗析改为投影法演示,这样便以可在较短时间内演示完毕,系统性强,现象明显,符合演示实验的特点,学生都能看得清楚。一、电泳实验目的: 使学生认识胶体微粒是带电荷的,在外电场的作用下向电极移动。实器仪器: 1、电源,用“J1205”型直流高压电 The experiments on colloidal properties demonstrated in current high school chemistry textbooks, except for the “Tyndar phenomenon”, the electrophoresis and dialysis performed by textbooks are not obvious, and take a long time, students cannot see clearly, and now we have electrophoresis and dialysis. Instead of the projection method demonstration, the demonstration can be completed in a relatively short period of time. The system is strong, the phenomenon is obvious, and the characteristics of the demonstration experiment are met. Students can see clearly. First, the purpose of electrophoresis experiments: To make students realize that colloidal particles are charged, and move to the electrodes under the action of an external electric field. Actuator instrument: 1, power supply, using “J1205” type DC high voltage