《自然》教材第五册的“力和运动”单元(包括第十至十七课和第十九至二十一课),谈到了许多力的作用。我们常说某物体受到了浮力,某物体受到了压力,运动的物体受到了摩擦力,静止的物体受到了地球引力(重力),此外,还有拉力、推力、阻力、风力、水力……看来力是无所不在的。这些都是力的存在的方式。那么我们是基于什么事实来认识力的存 The “Force and Movement” unit of Volume 5 of the Nature textbook, covering Lessons 10 through 17 and Lessons 19 through 21, speaks of many forces. We often say that an object is subjected to buoyancy, an object is under pressure, a moving object is subjected to friction, and a stationary object is gravitational to the Earth (gravity). In addition, there are tension, thrust, resistance, wind, water ... To force is ubiquitous. These are ways of existence of force. Then we are based on what facts to save knowledge