Foundations of Mathematical Thinking · Senior Infants

Active learning ideas

Exploring Triangles

Young learners grasp geometric concepts best through active engagement. For exploring triangles, hands-on activities allow children to physically manipulate shapes, build them, and find them in their environment, solidifying abstract ideas through concrete experiences.

• NCCA Curriculum Specifications
• NCCA: Junior Cycle - Geometry and Trigonometry - GT.3

• 20–30 min
• Pairs → Whole Class
• 3 activities

Activity 01

• Stations Rotation
• 30 min · Small Groups

Shape Sorting: Triangle Detectives

Provide a collection of various shapes, including different types of triangles. Students work in small groups to sort the shapes, placing all triangles into one category and then further sorting the triangles by side length (equal vs. unequal) or angle appearance (sharp vs. wide).

Can you point to all the triangles on this page?

Facilitation Tip

During Stations Rotation, ensure each station provides a clear, manageable task related to triangle properties to keep student focus high.

• Remember
• Understand
• Apply
• Analyze
• Self-Management
• Relationship Skills

Activity 02

• Stations Rotation
• 25 min · Pairs

Building Triangles: Straw and Playdough

Students use playdough to create vertices and straws to form the sides. They can experiment with making different types of triangles by adjusting the lengths of the straws, discussing the resulting shapes and properties.

How many sides does a triangle have , let us count.

Facilitation Tip

For Experiential Learning with the straw and playdough activity, encourage students to verbalize their construction process, reinforcing the connection between the materials and the geometric concept.

• Remember
• Understand
• Apply
• Analyze
• Self-Management
• Relationship Skills

Activity 03

• Stations Rotation
• 20 min · Individual

Triangle Hunt: Classroom Safari

Challenge students to find and draw examples of triangles they see in the classroom environment. They can then share their drawings and discuss where they found the triangles and what makes them triangles.

Can you draw a triangle for me?

Facilitation Tip

During the Triangle Hunt, prompt students to explain *why* they identified an object as a triangle, connecting their observations to the defining characteristics.

• Remember
• Understand
• Apply
• Analyze
• Self-Management
• Relationship Skills

A few notes on teaching this unit

Focus on tactile and visual experiences to introduce triangles. Use simple language to describe key features like 'three sides' and 'three corners.' Encourage exploration and discovery rather than rote memorization, allowing children to build their own understanding through play and observation.

Students will confidently identify triangles by their three sides and vertices. They will be able to sort triangles based on observable differences in side lengths and angles, and locate triangles in familiar surroundings, demonstrating a foundational understanding of shape properties.

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Watch Out for These Misconceptions

• During the Triangle Hunt, watch for students who only identify triangles that are oriented with a flat base at the bottom.

  Redirect by showing them a triangle they drew or found and rotating it, asking if it is still a triangle and why. Then encourage them to look for triangles in different orientations around the room.

• During Shape Sorting, watch for students who group all triangles together without noticing differences in side lengths or corner appearances.

  Ask students to compare two triangles side-by-side, prompting them to describe what is the same and what is different about their sides and corners to guide them toward distinctions like 'long side' or 'pointy corner'.

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Methods used in this brief

• Stations Rotation