Students understand that shapes are not defined by orientation (triangles cannot be "upside down" because orientation is not a defining characteristic of a triangle) or size, and can identify them by defining attributes such as number of sides.
Understanding the Standard:
- Students sometime have difficulty distinguishing shapes. Tracing shapes is one way to help students overcome this difficulty.
- Students need practice looking at and manipulating the same shape in different orientations and different sizes.
- Students can sometimes be fooled by long, pointy triangles, obtuse triangles, and four-sided figures that look like a triangle with a "dent" in one side. It is important to make this clear to students and include activities that focus their attention on the number of sides a shape has.
- Have students pick up a book, turn it over, and ask if is is still a book. Then do the same thing with a triangle. Finally, turn over a large cut out of the letter b. Point out that altough a letter can become a different letter when you turn it or flip it, other things remain the same. Ask a student (say, Alex) to stand up and turn around. Is it still Alex? Reinforce this idea with shapes.
Specific Questions to Focus Instruction:
- Can students identify a number of variants of a shape, such as obtuse triangles or very long, skinny rectangles?
- Can students identify a non-regular polygon with the appropriate shape name? For instance, if a triangle is not equilateral, will the student still identify it as a triangle?
- Can students identify a square without its being placed with its side parallel to the edge of the page? For instance, would they call it a diamond instead of a square if it were placed on its tip (i.e., with the diagonal perpendicular to the edge of the page)?
- Can students describe shapes using phrases like "straight edges", "sharp corners", "round", "pointy", "large, "small", etc.?
: Students recognize shapes by their appearance (rather than their attributes).
At Grade Level:
Students understand that shapes have defining attributes and can correctly identify shapes regardless of size or orientation.
Students will distinguish between defining attributes (e.g., triangles are closed and three-sided) versus non-defining attributes (e.g., color, orientation, overall size); build and draw shapes to possess defining attributes.