Growth Point 2

Properties of Shape Growth Points activities

2. Classification of shapes, attending to visual features

Can sort and compare shapes, using some geometrical language to describe features.

Feely box

Materials: Cardboard box with a concealed opening on the side, pattern/attribute blocks.

Activity: The teacher places a shape into the box and asks a student to place their hands into the box and feel the shape. The student then uses geometric language to describe the shape they can feel. For example, ‘I can feel three corners’, ‘I can feel three sides’.

The teacher encourages the rest of the class to make a picture in their head while they are listening to the description. Students are invited to guess what shape is in the box before it is revealed.

Related key ideas: Properties, classification.

Variation: The students with their hands in the box can only answer Yes or No questions. Other students ask questions to try and guess which shape is in the box.

Inside triangles

Materials: Geoboards, rubber bands, geodot paper, pencils, scissors.

Activity: Invite students to make a triangle on their geoboard. Students gallery-walk to see how other students have created their triangle. Ask, how are all of the triangles the same/different? Can you list the things that make them all triangles? Draw out properties like three straight sides/corners. Look inside the triangle, how many pegs are there? How is this the same/different?

Ask students to make a triangle with only one peg in it then draw it on the geodot paper. Repeat the process with two pegs, three pegs and so on. After students have drawn all of the possible solutions, ask them to cut out their triangles.

As a class, compare all of the one-peg triangles. What do you notice about them? How can we check/prove that they are all the same? Which triangles are the same/different? Encourage students to rotate their shapes and overlap them. Repeat with all the other peg combinations.

Write a class summary of ‘what makes a triangle?’ and ‘what doesn’t make a triangle?’ Include aspects that have no impact such as size.

Related key ideas: Properties, classification, orientation.

Variation: Ask students to draw on the geopaper two triangles that meet at one point. How many different ways can you do this? Repeat the process but now join them at two points. Ask, what do you notice? What shapes can you create by joining triangles? (see example below).

Making shapes

Materials: Kinder squares.

Activity: Teacher asks students to fold their kinder square in half along the diagonal to create two triangles. Students then cut along the fold line to create two separate shapes. Students are then asked to join their two triangles to make a new shape. When joining their shapes, they must make sure that the sides they are joining are of equal lengths (see examples below).

Students are asked to name their shape and justify why it belongs to that group. They then compare their new shapes with others in the class and explain which are the same and which are different and why.

Related key ideas: Properties, classification.

Variation: Students pair with another student. They now have four triangles they need to join to make a new shape. Ask students to name all the new shapes they have made.

Exploring pattern blocks

This task has been adapted from PASMAP Book 1 (Mulligan & Mitchelmore, 2016a) with permission from the authors.

Materials: Pattern/attribute blocks.

Activity: Introduce the term ‘attribute’ to the students as being the feature of something, in this case a shape, that determines what group(s) it belongs to. Looking at the collection of objects, brainstorm what could be some of the attributes you might use to sort them. Some of these (e.g. colour, size) may not be geometric attributes but allow them to be included in the brainstorm. Using the class brainstorm, sort the attributes into two groups: ones that help you describe shape, and those that do not.

In pairs, ask students to select two objects from a collection which they think have the same attribute. They then need to describe what the attribute is and why they are the same.

For example, if a student says that an object is ‘round’, ask if anyone knows the name of a flat round shape (‘circle’).

You want to be encouraging students to look at the flat surfaces of objects when describing the attributes. As geometrical vocab arises, begin making a list of words that students can use to describe shape.

Related key ideas: Features, properties.

Variation: Name an attribute (e.g. ‘triangle face’) and ask students to find all the objects that match it either by shape or size.

Congruent shapes

This task has been adapted from PASMAP Book 1 (Mulligan & Mitchelmore 2016a) with permission from the authors.

Materials: Pattern/attribute blocks.

Activity: Present the students with a variety of pattern blocks. Ask the students to sort the blocks into groups of the same shape. What is the same/different in each group?

Ask students to stack the blocks within each group on top of each other. What do you notice? Why do they fit on top of each other? Can you name each group? Will all triangles (or other shapes) always fit on top of each other like this?

Related key ideas: Features, properties, classification, orientation.

Variation: Ask the students if they can think of any shapes that are not represented in these groups. What do you call them? What makes them different? Why can’t they be included in one of your groups?

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