做观察酒精和水混合时体积变小的实验通常是用量筒量取酒精和水混合后进行观察 .这样操作不仅要几次观察记忆量筒中的液面刻度 ,而且耗费酒精的量较大 .下面所设计的观察酒精和水混合时体积变小的实验 ,不仅操作简便 ,耗费酒精量少 ,而且教学视觉效果好 .演示管的制作截取一根 The observation that the volume of the alcohol and water is mixed when observing the mixture of alcohol and water is usually observed after the cylinder is mixed with alcohol and water. This operation requires not only several observations of the liquid surface mark in the memory cylinder, but also a large amount of alcohol consumption. The experiment designed to observe the small volume of alcohol and water mixed is not only easy to operate, consumes less alcohol, but also has good visual effects for teaching. The production of a demonstration tube intercepts a