Kevin Williams is the Program Consultant for K-8 Numeracy with the Dufferin Peel Catholic District School Board, and a senior tutor with Homework Help, the free online math resource for kids in grades 7 to 10.
Geometry and spatial sense is one of the five content strands in the Ontario Math Curriculum that is gaining increased focus lately. Geometry explores and investigates the properties and characteristics of shapes, transformations, and location. In addition to focusing on developing this specific knowledge, this strand also looks at the idea of geometric relationships between shapes
Children entering school already have some geometric knowledge and so as they move through the grades we want to provide them with plenty of experiences to investigate and explore shapes (both two-dimensional and three-dimensional) in order to deepen their knowledge.
Initially children begin to identify, sort and classify shapes by their attributes. This could be by size, shape, colour, number of sides, number of corners (vertices) etc…
As they move into grade 2 the focus of their exploration then moves more to looking specifically at sorting and classifying based on geometric properties. In the primary and junior grades children focus on different types of polygons and cylinders and prisms with specific types being identified in particular grades. Ask your child what shapes they’ve been exploring and talking about. Here is a quick geometry glossary:
Attribute: a characteristic that is not specific to the shape and it may be arbitrary like size.
Geometric property: a characteristic that is specific to a particular shape or family of shapes (e.g. squares have four sides that are all the same length).
Polygons: a closed shape created by three or more line segments.
Prisms: a 3-D figure with two parallel congruent faces joined together by rectangular faces.
Pyramids: a 3-D figure with a polygon base and the other faces are all triangles that meet at a common vertex.
Helping Your Child with Geometry:
There are plenty of fun and easy ways to help your child with geometry.
- Go on a shape scavenger hunt or play “I SPY” using 2-D shapes and 3-D figures as what you are looking for. Don’t just use “regular” shapes. For example if you are looking at triangles, look at all different kinds of triangles and talk about what they all have in common, and how they are different.
- Build 3-D figures with play dough or with toothpicks and marshmallows! Ask your child to name the figures and explore them. You can ask questions like what shapes do you see in the 3-D figure? How many faces are there? How many corners (vertices)? Compare different 3-D figures. What is the same? What is different?
- WHAT SHAPE AM I? Draw a shape. Without showing it to your child have your child try to draw it by asking you questions about it. You can respond with only YES / NO answers. This can help focus observations about shape properties.
- Build and deconstruct shapes. Build different shapes by combining shapes your child knows and decompose shapes by cutting them apart. (e.g. Take a rectangle and have your child decompose it to see what shapes make up a rectangle. Two triangles for example).
Squares, rectangles and parallelograms can be decomposed into two congruent triangles.
Many objects and pictures consist of multiple shapes/figures. It’s important for children to see shapes and figures in the world around them.