What is a hemisphere?
A hemisphere is half of a sphere: a round dome with one flat circle face.
The answer
A hemisphere has 2 faces, 1 edge and 0 vertices.
Hemisphere diagram and properties
| Property | Count |
|---|---|
| Faces1 flat circle and 1 curved face | 2 |
| Flat faces | 1 |
| Curved faces | 1 |
| Edges | 1 |
| Vertices (corners) | 0 |
Primary schools count the curved dome as a face, and the circle where it meets the flat face as a curved edge.
Key facts about the hemisphere
- "Hemi" means half, so a hemisphere is half a sphere.
- Its one edge is the circle where the flat face meets the curved face.
- It can rock on its curved face and stand still on its flat face.
Where you see it
A bowl, half an orange cut across the middle and a dome on top of a building.
The common mistake
Saying a hemisphere has no flat face because a sphere has none. Cutting the sphere in half makes a new flat circle face.
An 11+ style question
A hemisphere has a flat face. What 2D shape is it, and how many edges does the hemisphere have?
Answer: A circle, and 1 edge
- Cutting a sphere in half through its centre leaves a flat face shaped like a circle.
- The flat face meets the curved face along one circle, so there is 1 edge.
Related shapes and skills
More shapes
Questions parents ask
How many faces, edges and vertices does a hemisphere have?
A hemisphere has 2 faces, 1 edge and 0 vertices. A hemisphere has no paper net: its curved face cannot lie flat without stretching or tearing. Try flattening half an orange peel and it splits.
How many hemispheres make a sphere?
Two. Cut a sphere through its centre and you get two identical hemispheres. That is why the Earth is split into the northern and southern hemispheres, above and below the equator.
Shape questions are quick marks in the 11+
Angles, symmetry, nets and 3D shapes come up in 11+ maths and non-verbal reasoning. The free diagnostic checks maths, English and both kinds of reasoning, and shows what to practise next. No card is required.