# K.G.A.3

Identify shapes as two-dimensional (lying in a plane, “flat”) or three-dimensional (“solid”).

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## Summary:

Two-dimensional shapes are flat, like a drawing or tile, while three-dimensional shapes can be used as containers or building blocks. Students do not initially see any difference between flat and solid shapes, and that is the crux of this standard. Students need experience thinking about whether shapes are solid or flat while they interact with them.

## Understanding the Standard:

• Constructing two-dimensional shapes using computer graphics programs is one way to explore the attributes of these shapes.
• Students will benefit from opportunities to explore the classroom for objects that have two-dimensional or three-dimensional shapes.
• Teachers need to model the correct names of three-dimensional shapes versus two-dimensional figures (for example, “sphere” vs. “circle”).
• Drawing with flat shapes and building with solid shapes should make a prominent appearance in the classroom.
• Focus on language use. Since kindergarteners cannot write, student talk should also pervade the classroom interactions.

## Specific Questions to Focus Instruction:

• Are students able to describe the shape of a physical object?
• Can students describe the position of an object relative to another object?
• Are students able to distinguish between a two-dimensional and a three-dimensional shape?
• Can students explain that a two-dimensional shape is flat, while a three-dimensional shape is not flat (a kindergarteners's way of saying that it has length, breadth, and width)?
• Can students identify the two-dimensional shapes that are found on the faces of three-dimensional shapes?
• Can students find examples of three-dimensional shapes in their environment?

## Skills

Prior to: Students can identify a shape by its appearance, but may not have grasped the concept of two-dimensional (flat) and three dimensional (solid) shapes.