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Flat vs Solid Shapes

Distinguish two-dimensional (flat) shapes from three-dimensional (solid) shapes

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What a learner can do afterwards

  • Sort shapes into 'flat' and 'solid' groups
  • Explain that a circle is flat but a sphere is solid
  • Identify whether a given shape is 2-D or 3-D

The lesson

Some shapes are flat. Some shapes are solid. A flat shape has no inside space. A solid shape takes up space, like a block.

A circle is flat. It has no inside space.
Try it together

A ball is shaped like a sphere. It is solid, not flat. You can hold a ball and roll it.

Good to know

Ask yourself: can I draw it flat on paper? If yes, it is a flat shape. If it takes up space, it is solid.

Flat shapes have no space inside. Solid shapes take up room, like a block.

Watch it

Where it sits

Where this leads

Jobs that lean on this skill. Follow one to see everything it is built on.

Then practise

8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.

Flat vs Solid Shapes · Mathematics, ages 5 to 6 · LightMySky