Sphere has many applications in mathematics. For example, sphere is one of the basic objects in three-dimensional geometry, and it is the basis of many other geometric shapes. In addition, the sphere also appears in many branches of mathematics, such as topology, algebra, calculus, probability theory and so on. Sphere is a common research object in topology because it has many unique properties, such as connectivity, compactness and homeomorphism. In calculus, spherical surface also has many applications, for example, the volume formula of rotating body is related to spherical surface.