Curious Investigators: Exploring Our World · 3rd Class · Design and Engineering · Summer Term

Materials for Building

Students will explore how the properties of materials influence their suitability for construction.

• NCCA Curriculum Specifications
• NCCA: Primary - Materials
• NCCA: Primary - Energy and Forces

About This Topic

In this topic, students examine how properties such as strength, flexibility, hardness, and waterproofing determine a material's suitability for building structures like bridges, towers, and shelters. They select materials for specific parts of a design, test them under load or force, and evaluate outcomes for durability and safety. This aligns with NCCA Primary strands on Materials and Energy and Forces, where students justify choices based on observed properties.

Students connect material properties to real-world engineering by designing tests to compare items like wood, plastic, paper, and fabric. They learn that forces like pushing or pulling affect structures differently depending on the material, fostering skills in prediction, observation, and evaluation. Group discussions help them articulate why a flexible material suits a bridge joint but not a tower base.

Active learning shines here because students gain concrete understanding through direct testing and iteration. When they build prototypes, apply weights, and record failures, abstract properties become visible and memorable, building confidence in engineering design processes.

Key Questions

1. Justify the selection of specific materials for different parts of a structure.
2. Evaluate how material properties impact a structure's durability and safety.
3. Design a test to compare the strength of different building materials.

Learning Objectives

• Compare the strength of different building materials when subjected to a consistent load.
• Evaluate how material properties like flexibility and waterproofing affect a structure's performance in simulated environmental conditions.
• Design and conduct a controlled experiment to test the load-bearing capacity of a paper bridge.
• Justify material choices for specific components of a model shelter based on observed properties.

Before You Start

Properties of Materials

Why: Students need to be familiar with basic material properties like hardness, texture, and absorbency before exploring their use in construction.

Forces and Motion

Why: Understanding concepts like pushing, pulling, and gravity is essential for testing material strength and structural stability.

Key Vocabulary

Strength	The ability of a material to withstand a force without breaking or deforming permanently.
Flexibility	The ability of a material to bend or change shape without breaking, and return to its original form.
Waterproofing	The quality of a material that prevents water from passing through it.
Durability	The ability of a material or structure to last for a long time without significant damage or wear.

Watch Out for These Misconceptions

Common Misconception

The heaviest material is always the strongest.

What to Teach Instead

Weight does not determine strength; testing shows light materials like bamboo outperform heavy ones in bending. Hands-on stacking challenges let students compare directly and revise ideas through peer comparison.

Common Misconception

All plastics are equally waterproof.

What to Teach Instead

Different plastics vary in absorbency; experiments with water exposure reveal this. Active soaking tests followed by weighing help students observe and quantify differences, correcting assumptions via evidence.

Common Misconception

Shiny materials make the best buildings.

What to Teach Instead

Appearance misleads; dull cardboard may outlast foil under load. Building and stress-testing prototypes allows students to prioritize function over looks through iterative trials.

Active Learning Ideas

Testing Stations: Material Strength

Prepare stations with materials like straws, popsicle sticks, and cardboard. Students drop weights or stack books to test breaking points, record results on charts, and discuss which material holds most load. Rotate groups every 10 minutes.

45 min·Small Groups

Build Challenge: Bridge Design

Provide assorted materials and challenge pairs to build a bridge spanning 30 cm that holds a toy car. They justify material choices beforehand, test spans, and redesign based on failures. Share successes class-wide.

50 min·Pairs

Property Sort: Material Matching

Lay out material samples and structure cards like 'tower base' or 'roof'. Individuals sort and label with properties, then pairs justify choices and test one prediction by bending or wetting samples.

30 min·Pairs

Force Investigation: Push and Pull

Use string, rubber bands, and blocks for small groups to apply forces to structures. Predict deformation, measure changes with rulers, and vote on best materials for tension or compression.

40 min·Small Groups

Real-World Connections

• Civil engineers select specific materials, like steel for bridges and concrete for foundations, considering their strength and durability to ensure public safety.
• Architects choose materials for buildings based on properties such as insulation, waterproofing, and aesthetics, impacting how comfortable and long-lasting a home or office will be.
• Manufacturers of tents and outdoor gear use waterproof and flexible fabrics to create shelters that protect people from the elements.

Assessment Ideas

Quick Check

Present students with images of different structures (e.g., a bridge, a tent, a house foundation). Ask them to write down one material used for each and explain why that material is suitable for that specific part of the structure.

Discussion Prompt

Pose the question: 'If you were building a roof for a playhouse that gets a lot of rain, what material would you choose and why?' Facilitate a class discussion where students share their reasoning, focusing on waterproofing and durability.

Exit Ticket

Give students a small sample of two different materials (e.g., a piece of cardboard and a piece of fabric). Ask them to describe one test they could perform to compare their strength and one test to compare their flexibility.

Frequently Asked Questions

How do I teach material properties for building in 3rd class?

Start with familiar objects, demonstrate properties like flexibility by bending samples, then let students test predictions on simple structures. Use charts for recording to build data skills. Link to key questions by having them justify choices in designs, reinforcing NCCA standards on materials and forces.

What active learning strategies work best for materials for building?

Station rotations for testing strength, flexibility, and waterproofing engage all students kinesthetically. Collaborative bridge builds encourage material justification and redesign after failure. These approaches make properties tangible, promote talk for learning, and mirror engineering practices, deepening retention over lectures.

How can students evaluate structure safety?

Guide them to test prototypes with weights or shakes, noting cracks or wobbles. Criteria checklists for durability help structure observations. Discussions on real bridges connect tests to safety, aligning with evaluating material impact per curriculum.

What materials should I use for building tests?

Everyday items like straws, cardboard, wooden sticks, foil, fabric, and plastics work well; they are safe, cheap, and show varied properties. Pre-test for hazards. This selection supports fair comparisons and student-led inquiries into strength and suitability.