即时速度在高中物理课程里是在讲变速运动中引出的重要物理概念。但是在课堂上讲解这个概念时由于没有实验仪器,老师讲不好,学生不好理解,在教学过程中对于这内容的实验问题一直没有得到解决。我们则经过多次试验,成功地制作了一个实验仪器,叫做即时速度演示器(以下简称演示器)经过教学实践,效果良好,学生反应也较好。此文主要介绍一下它的基本原理。我们知道,为了更精确地描述变速运动,必须知道 Instantaneous speed is an important physical concept in high school physics courses that leads to variable speed movements. However, when the concept was explained in class, because there was no experimental apparatus, the teacher did not speak well, and the students did not understand well. In the course of teaching, the experimental problems of this content have not been resolved. After many experiments, we successfully produced an experimental apparatus called the Instant Speed ​​Demonstrator (hereafter referred to as the demonstrator). After the teaching practice, the results were good and the students responded well. This article mainly introduces its basic principles. We know that in order to describe the variable speed motion more accurately, we must know