初三物理“焦耳定律”的演示实验方法,是利用煤油的受热膨胀来反映电流产生热的多少,我对实验方法和装置作了改进,利用空气取代煤油。改进后,不仅可见度大直观性强,而且使实验时间从原来的约20分钟减少到5分钟左右。一、实验装置二、实验方法 1.先将四根金属电阻丝(2欧一根和5欧三根)如图1所示分别装入四个烧瓶中,用滴管往弯曲的玻璃管中滴入约1厘米长的红色水珠,烧瓶塞上开有一通气孔,孔内临时插一根约5厘米长的铁丝塞,将该通气孔堵塞,若将铁丝拔去,则可以方便地调节水珠 The demonstration experiment method of the third-generation physics “Joule’s Law” uses the thermal expansion of kerosene to reflect the amount of heat generated by the current. I have improved the experimental methods and devices and used air to replace kerosene. After the improvement, not only the visibility is strong and intuitive, but also the experimental time is reduced from about 20 minutes to about 5 minutes. First, the experimental device Second, the experimental method 1. First four metal resistance wire (2 euro and 5 euro three) as shown in Figure 1 were loaded into four flasks, with a dropper to the glass tube in the drop Into the red ball of about 1 cm long, the flask is plugged with a vent hole, and a wire plug of about 5 cm length is temporarily inserted into the hole to block the vent hole. If the wire is pulled out, it can be easily adjusted. Waterdrop