这里介绍一个便于学生理解液体流速与压强的关系，激发学生应用物理知识，力图解决实际问题为动机的小实验．在自来水龙头下接入一个具有三通口的金属棒（铁的、铜的都行，俗称“小热水器”），其总体示意图如图1所示，“小热水器”具体尺寸见图2．当打开水龙头，冷水经“热水 Here is a small experiment that allows students to understand the relationship between liquid flow rate and pressure, to stimulate students to apply physical knowledge, trying to solve practical problems as motivation. Access to a tap with a three-way mouth of the metal bar (iron, copper all, commonly known as “small water heater”), the overall schematic diagram shown in Figure 1, “small water heater” specific dimensions shown in Figure 2. When the tap is turned on, the cold water is “hot water”