自然界是千姿百态、千变万化的。人类从不同的角度研究大自然,就形成了数学、物理、化学、生物等各门自然学科。例如,为了帮助排球运动员提高成绩,物理学可以研究一下,运动员怎样弹跳和扣球,球才能打得又准又猛;生物学可以研究一下,运动员怎样安排饮食起居和锻炼强度,才能使身体适应比赛要求;心理学则可以研究一下运动员的意志、情绪等精神因素,以便增强胜利信心。分门别类地研究大自然,目的在于化繁为简。在各门学科里,也遵循同样的原则,把错综复杂的事物归结为一些简单的问题进行研究。物理学的一个重要方法就是建立理想模型。所谓理想模型,就是为了便于抓住本质、解决问题,而对事物取其枝干、去其蔓叶后建立的抽象模型。在物理学中,质点、刚体、理想气体、 Nature is varied and ever-changing. Human beings study nature from different angles, forming mathematics, physics, chemistry, biology and other natural disciplines. For example, to help volleyball athletes improve their performance, physics can study how athletes bounce and smash the ball before the ball can be played quasily and fiercely. Biology can study how athletes arrange daily diet and exercise intensity before they can adapt. Competition requirements; psychology can study the athlete’s will, emotions and other spiritual factors in order to enhance victory in confidence. Studying nature in different ways aims at simplifying and simplifying. In all disciplines, the same principles are followed, and the intricate things are summed up as simple questions to study. One important method of physics is to establish an ideal model. The so-called ideal model is an abstract model that is created for the purpose of grasping the nature and solving problems, and taking the branches and leaves of things. In physics, particles, rigid bodies, ideal gases,