Maths topic

3D objects

3D objects are solid objects. They take up space and can have flat faces, curved surfaces, edges and vertices.

Practise 3D objects Explore solids Back to topics

the big idea

A 3D object is solid. To name and describe it, look at its faces, edges, vertices and curved surfaces.

solid takes up space
parts faces, edges, vertices
name cube, sphere, cylinder

choose a 3D object

Pick a solid object and read its important properties.

cube

cube

faces6 square faces edges12 edges vertices8 vertices featureall faces are equal squares

all faces are equal squares

2D shapes and 3D objects

A 2D shape is flat. A 3D object is solid and takes up space.

  • 2D shapes have length and width.
  • 3D objects have length, width and depth.
  • A square is flat, but a cube is solid.
  • A circle is flat, but a sphere is solid.
2D: flat
square circle
length and width
3D: solid
cube sphere
length, width and depth

common 3D object names

Some 3D object names are learned by matching the object and its properties.

  • A cube has 6 equal square faces.
  • A rectangular prism is box-shaped.
  • A sphere is round all the way around.
  • A cylinder has two circular faces and a curved surface.
  • A cone has one circular face and a point.
  • A pyramid has triangular faces that meet at a point.
cube 6 square faces 8 vertices

all faces are equal squares

rectangular prism 6 rectangle faces 8 vertices

box-shaped prism

sphere 0 flat faces 0 vertices

1 curved surface

cylinder 2 circular faces 0 vertices

1 curved surface

cone 1 circular face 1 vertex

1 curved surface

square pyramid 5 faces 5 vertices

triangular faces meet at a point

parts of 3D objects

Faces, edges and vertices help us describe 3D objects.

  • A face is a flat surface.
  • An edge is where two faces meet.
  • A vertex is a corner point where edges meet.
  • Some 3D objects also have curved surfaces.
face edge vertex
face: flat surface edge: where faces meet vertex: corner point

counting properties

Counting faces, edges and vertices helps us name and compare 3D objects.

  • A cube has 6 faces, 12 edges and 8 vertices.
  • A rectangular prism has 6 faces, 12 edges and 8 vertices.
  • A sphere has one curved surface and no edges or vertices.
  • A cylinder has flat circular faces and a curved surface.
object faces edges vertices
cube 6 square faces 12 edges 8 vertices
rectangular prism 6 rectangle faces 12 edges 8 vertices
sphere 0 flat faces 0 edges 0 vertices
cylinder 2 circular faces 2 curved edges 0 vertices
cone 1 circular face 1 curved edge 1 vertex
square pyramid 5 faces 8 edges 5 vertices

prisms and pyramids

Prisms and pyramids are groups of 3D objects with special properties.

  • A prism has two matching end faces.
  • A rectangular prism has rectangle faces and is box-shaped.
  • A pyramid has a base and triangular faces that meet at one vertex.
  • The base is the face the object can sit on.
prism matching ends
pyramid faces meet at a point

nets

A net is a flat pattern that can fold to make a 3D object.

  • Nets are flat before they are folded.
  • The shapes in the net become the faces of the 3D object.
  • A cube net is made from 6 squares.
  • Different nets can fold into the same 3D object.
6 squares

property words

These words help us describe and sort 3D objects.

1 face flat surface

a flat surface on a 3D object

2 edge line

where two faces meet

3 vertex corner

where edges meet at a point

4 curved surface bent surface

a surface that is not flat

5 net flat pattern

a flat pattern that folds into a 3D object

6 volume space inside

how much space a 3D object takes up

3D object facts

cube 6 square faces
sphere 1 curved surface
cylinder 2 circular faces
cone circle and point
cube net 6 squares
prism matching ends

real world examples

dice dice are cubes
boxes many packages are rectangular prisms
balls balls are spheres
cans cans are cylinders
traffic cones cones have circular bases and points
packaging nets fold into boxes and cartons

quick 3D object quiz

Try a few 3D object ideas. This quiz only asks about ideas shown on this page.

Which 3D object is shaped like a ball?

What is a flat surface on a 3D object called?

What is an edge?

Which object has two circular faces?

What does a net do?