投影器是幻灯的一种类型,一般用于会场或课堂上进行书写投影,故通常称为书写投影器。投影器也可用来放映幻灯片,放映画面比普通幻灯机大。若将投影器用来放映化学实验实际现象(以后简称为“投影实验”),常可收到生动、直观、鲜明的效果,因此很适于进行化学课堂演示实验。投影实验操作简单,药品消耗量小,不需特殊的投影专用器皿,一般实验可在培养皿、表面皿、小烧杯或玻璃片上进行,都能收到满意的投影效果,因为投影具有 Projector is a type of slide, usually used for writing projection in the venue or classroom, it is often called a projector. Projector can also be used to show slide shows screen larger than normal slide projector. If the projector is used to display the actual phenomenon of chemical experiment (hereinafter referred to as “projection experiment”), it can often receive vivid, visual and vivid effects, so it is suitable for conducting chemical classroom demonstration experiments. Projection experiment simple operation, drug consumption is small, without special projection special vessels, general experiments in Petri dishes, watch glass, small beakers or glass, can receive satisfactory projection results, because the projection has