Nepedia
Back to Discover
Fluent Reader
🔢

Three-dimensional space

math Maturity 7-9 Vital Level 3 Next article →

Imagine you are standing in a large room. To find a fly buzzing in the air, you need more than just a flat map. You need to know how far it is from one wall, how far from another, and how high it is from the floor. This is the idea of three-dimensional space, or 3D space.

Coord planes color
Coord planes color

In this space, we use three values called coordinates to find any single point. These values often represent length, width, and height. Most scientists use this math to model our physical universe. This is the world where all matter exists.

Sphere wireframe 10deg 6r
Sphere wireframe 10deg 6r

Math helps us describe how things move and sit in this space. We can use three axes that cross at a single starting point called the origin.

Coord planes color
Coord planes color

These axes are perpendicular, which means they meet at right angles. You can find a point by measuring its distance along each of these three lines. There are other ways to do this too, such as using cylindrical or spherical coordinates.

Sphere wireframe 10deg 6r
Sphere wireframe 10deg 6r

You can also think about lines and planes. Two points always make a straight line. Three points can create a flat plane.

Relations between planes
Relations between planes

If you have four points, they might define the whole 3D space.

People have studied these shapes for a very long time. The philosopher Aristotle recognized that there were three dimensions. Much later, the mathematician Euclid wrote about 3D geometry in his famous books.

Hexahedron
Hexahedron

He studied how lines and planes work together. He also looked at shapes like pyramids and spheres. In the 17th century, René Descartes helped create analytic geometry.

Hexahedron
Hexahedron

He used coordinates to describe space. Pierre Fermat also worked on similar ideas at the same time. These thinkers helped us turn shapes into math we can solve.

Many famous mathematicians added to our understanding in later years. Isaac Newton introduced a different way to use coordinates. In the 1800s, William Rowan Hamilton created a system called quaternions.

Cross product vector
Cross product vector

He used this to define terms like scalar and vector. Later, Josiah Willard Gibbs helped create the modern way we write about vectors.

Cross product vector
Cross product vector

He used his classroom notes to teach these ideas. Other mathematicians like Leonhard Euler studied how curves bend on surfaces.

Cross product vector
Cross product vector

Their work built the foundation for how we study space today.

We can see 3D math in many beautiful shapes. Some shapes are very regular, like the five Platonic solids.

Tetrahedron
Tetrahedron

These include the cube and the icosahedron.

Icosahedron
Icosahedron

There are also four other shapes called Kepler-Poinsot polyhedra.

SmallStellatedDodecahedron
SmallStellatedDodecahedron

You can also find round shapes like a sphere. A sphere is made of points that are all the same distance from a center.

Sphere wireframe 10deg 6r
Sphere wireframe 10deg 6r

The solid part inside that sphere is called a ball. These shapes help us understand everything from tiny atoms to huge planets.

453 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (15)
File:Coord planes color.svg
Coord planes color.svg
File:Relations between planes.png
Relations between planes.png
File:Sphere wireframe 10deg 6r.svg
Sphere wireframe 10deg 6r.svg
File:Tetrahedron.svg
Tetrahedron.svg
File:Hexahedron.svg
Hexahedron.svg
File:Octahedron.svg
Octahedron.svg
File:Dodecahedron.svg
Dodecahedron.svg
File:Icosahedron.svg
Icosahedron.svg
File:SmallStellatedDodecahedron.jpg
SmallStellatedDodecahedron.jpg
File:GreatDodecahedron.jpg
GreatDodecahedron.jpg
File:GreatStellatedDodecahedron.jpg
GreatStellatedDodecahedron.jpg
File:GreatIcosahedron.jpg
GreatIcosahedron.jpg

+ 3 more

More to explore

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.