Lesson 3: Structural Materials – Wood and Engineered Wood
Duration of Days: 5
Lesson Objective
Students will be able to compare the properties of softwoods, hardwoods, and engineered wood products, evaluating their strength-to-weight ratios and analyzing industrial processes (like CLT and Glulam) that enhance wood's structural performance.
Why is wood considered a renewable and carbon-sequestering material?
How do we make wood stronger and more stable than nature intended?
What types of buildings or structures are ideal for using wood?
Softwood: Cellular organic material from needle-bearing trees like Pine, Fir, or Cedar.
Hardwood: Dense wood from broad-leaved trees like Oak, Maple, or Walnut.
Engineered Wood: Composite materials made by gluing wood pieces together, such as Plywood, Glulam, or Cross-Laminated Timber (CLT).
Carbon Sequestration: The process by which growing trees absorb and store carbon dioxide.
Strength-to-Weight Ratio: A material’s ability to bear heavy loads relative to its own mass.
HS-LS2-7: Design, evaluate, and refine a solution for reducing the impacts of human activities on the environment and biodiversity (applied to sustainable forestry).
HS-PS2-6: Communicate scientific and technical information about why the molecular-level structure is important in the functioning of designed materials.
Technical reading and data comparison; students must analyze cause-effect relationships in industrial wood processing and interpret strength testing data.
Description:
Day 1: History and Sustainability. Explore the evolution of wood from prehistoric shelters to mass timber construction. Discuss wood as a renewable resource that requires less energy to produce than steel or concrete.
Day 2: Softwoods vs. Hardwoods. Differentiate between wood types. Students learn that softwoods like Douglas Fir are common for framing, while hardwoods are often reserved for finishing or high-durability needs.
Day 3: The Engineering Revolution. Focus on engineered wood products. Analyze how Glulam allows for large curved members and how CLT enables multi-story wooden buildings.
Day 4: Hands-on Properties & Identification. Students participate in a Wood Identification Challenge using physical samples and conduct a Strength Testing Experiment to see how different species handle weight.
Day 5: Design Challenge. Groups design and build a small bridge using toothpicks and glue, followed by a Sustainable Forestry Debate on the environmental pros and cons of wood use.
Purpose: To explore the scientific properties and environmental benefits of wood, preparing students to evaluate it as a viable alternative to traditional high-load materials like steel.
DOK Level: 3 (Strategic Thinking) and 4 (Extended Thinking).
Real-World: Identifying the use of dimensional lumber (e.g., 2”x4” studs) in residential walls and floors and the growing use of mass timber in sustainable urban architecture.
Culturally Relevant Connections: Studying historical wooden architecture, such as Chinese pagodas or European half-timbered houses, to understand regional building traditions.
Students often believe all hardwoods are "harder" than softwoods; the lesson clarifies that Balsa is a hardwood despite being soft and fragile, while some softwoods are quite stiff.
Tactile Learners: Provide hands-on wood samples for physical comparison of grain and density.
Advanced Students: Provide additional research materials on cutting-edge carbon-capturing mass timber.
Struggling Learners: Use simplified diagrams of wood's cellular structure to explain its insulating properties.
Interactive Activity: Performance in the "Design Challenge: Wooden Bridge" strength test.
Summative Quiz: Structural Materials MCQ covering species identification and engineered wood advantages.
Slides: "1.4-Construction Material: Wood" and "1.2-Structural Materials-Wood".
Video List: 15 recommended educational videos on CLT, Glulam, and wood preservation.
Physical wood samples (Oak, Pine, Balsa, Cedar), toothpicks, and glue.