Cube

A cube is a three-dimensional solid in geometry. It has eight points where edges meet and twelve straight edges that are all the same length. The cube has six square faces, and all the faces are the same size. Because of its simple shape, the cube is a key example of a polyhedron.

Cubes are found in many parts of daily life and culture. They are used in toys, games, art, and buildings. In science, the shapes of crystals often look like cubes. Ancient thinkers like Plato wrote about cubes in his work Timaeus, linking the shape to the classical element of earth. A cube that measures one unit on each side is the standard way to measure volume in space.

Cubes are also important in mathematics. They can be combined with other shapes to make more complex solids. A cube can fill space completely without leaving gaps, forming a pattern called a honeycomb. The cube can also be shown as a graph — a set of points called vertices connected by lines called edges. This idea can be extended to higher dimensions, where the cube becomes part of a hypercube, such as the four-dimensional tesseract.

Properties

A cube is a solid shape with eight corners and twelve edges that are all the same length. These edges make six square faces, and all the faces are the same size. A cube is a special type of shape called a rectangular cuboid, which has six rectangular faces.

We can measure different parts of a cube. The diagonal across a face is found using the Pythagorean theorem. The space diagonal, which goes from one corner to the opposite corner through the inside of the cube, is also found using this theorem. The surface area of a cube is six times the area of one square face. The volume is found by multiplying the length of one edge by itself three times.

Appearances

Cubes appear in many interesting places! They are most commonly used as dice in games. Fun puzzle toys like the Rubik's Cube and Skewb are also shaped like cubes. In video games, Minecraft uses cubic blocks to build its world.

In nature and science, cubes show up too. For example, table salt often forms cubic crystals. Some molecules, like cubane, have atoms arranged in a cube shape. In space, small satellites called CubeSat are shaped like cubes.

Constructions

A cube has eleven different nets. These are flat shapes made of squares joined along their edges. When you fold these squares along the edges, they form the six faces of a cube.

In analytic geometry, a cube can be placed in a coordinate system. For a cube in the middle with edges straight up and down, the positions of its corners are given by coordinates like (±1, ±1, ±1). This means each coordinate can be either 1 or -1. The cube’s inside includes all points between -1 and 1 on each axis.

The cube can also be shown as a graph. A graph is a set of points (vertices) connected by lines (edges). This graph, called the cubical graph, has the same number of vertices and edges as the cube itself. It follows rules that show the shape of a cube.

Related topics

Construction of polyhedra

Many interesting shapes can be made from a cube. For example, by removing parts of the cube's faces, we can create a shape called the stellated octahedron. We can also attach other shapes to the cube's faces to make new solids, such as the elongated square pyramid and the elongated square bipyramid.

Polycubes

Main articles: Polycube and Dali cross

Polycubes are shapes made by joining one or more cubes together face-to-face. An example is the Dalí cross, named after the artist Salvador Dalí, which can be folded in four dimensions to form a tesseract.

Space-filling

A cube can fill space without any gaps, which means it can tessellate in three-dimensional space. This creates a pattern called a honeycomb. There are special types of these patterns, such as the cubic honeycomb, which uses only cubes.

Miscellanea

There are many interesting ways to arrange cubes. For example, cubes can be arranged to share the same center, creating uniform polyhedron compounds. Additionally, a cube can be represented on a sphere as a spherical cube, which has six spherical squares.