Flat vs Solid Shapes
Distinguish two-dimensional (flat) shapes from three-dimensional (solid) shapes
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
1 · Read
Some shapes are flat. Some shapes are solid. A flat shape has no inside space. A solid shape takes up space, like a block. Once you can tell them apart, you can sort the whole toy box into two piles.
A circle is flat. It has no inside space. You can draw it with one curved line.
A circle is flat. It has no inside space.
A ball is shaped like a sphere. It is solid, not flat. You can hold a ball and roll it.
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.
More to read
Polygons review
Flat shapes live on paper with no thickness. Circles, squares, and triangles are all flat. You can draw them but never hold them. Flat means two directions only.
9.5: Area and Volume of Geometric Figures and Objects
Solid shapes fill space and can be held. Cubes, spheres, cones, and cylinders are all solid. A ball is a solid sphere, a box is a solid box. Solids have faces you can touch all around.
At Home Learning Lesson Plan: Sort, Cleanup & Count!
Sorting splits shapes into flat and solid teams. Drop drawings in the flat tray and toys in the solid tray. A coin picture goes flat, a real ball goes solid. Every shape lands on exactly one team.
Right angles in shapes (informal definition)
Circles and spheres look alike but differ. A circle is flat like a pancake drawing, a sphere is round like a ball. Roll test them: spheres roll every way, circles cannot roll at all.
Explore more
2 · Watch
En anglaisTake it off screen
Where it sits
Learn first
This opens up
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
18 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.