as a sphere with a radius between 100 and 120 picometres. At the other end of the scale, the Earth has a volume of around . The largest possible volume in the observable universe is the observable universe itself, at by a sphere of in radius. Capacity and volume Capacity is the maximum amount of material that a container can hold, measured in volume or weight. However, the contained volume does not need to fill towards the container's capacity, or vice versa. Containers can only hold a specific amount of physical volume, not weight (excluding practical concerns). For example, a tank that can just hold of fuel oil will not be able to contain the same of naphtha, due to naphtha's lower density and thus larger volume. Calculation Integral calculus The calculation of volume is a vital part of integral calculus. One of which is calculating the volume of solids of revolution, by rotating a plane curve around a line on the same plane. The washer or disc integration method is used when integrating by an axis parallel to the axis of rotation. The general equation can be written as:where and are the plane curve boundaries. The shell integration method is used when integrating by an axis perpendicular to the axis of rotation. The equation can be written as: The volume of a region D in three-dimensional space is given by the triple or volume integral of the constant function over the region. It is usually written as: In cylindrical coordinates, the volume integral is In spherical coordinates (using the convention for angles with as the azimuth and measured from the polar axis; see more on conventions), the volume integral is Geometric modeling A polygon mesh is a representation of the object's surface, using polygons. The volume mesh explicitly define its volume and surface properties. Differential geometry In differential geometry, a branch of mathematics, a volume form on a differentiable manifold is a differential form of top degree (i.e., whose degree is equal to the dimension of the manifold) that is nowhere equal to zero. A manifold has a volume form if and only if it is orientable. An orientable manifold has infinitely many volume forms, since multiplying a volume form by a non-vanishing function yields another volume form. On non-orientable manifolds, one may instead define the weaker notion of a density. Integrating the volume form gives the volume of