Earth and Environmental Science · 40 minutes
Suggested grades 9–12 · Unit 2: Carbon and Resource Decisions · Lesson 2 of 2
Compare Resource Strategies Transparently
Evaluate competing metal-use options using economic, environmental and social criteria.
Mr. S Teaches · Original starter lesson · HS-EARTH-04 · Grade range is planning guidance.Watch, notice, discuss
Video choices for this lesson
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How Japan saved its biggest city from collapse - Roman Krznaric
By TED-Ed
Use historical repair and reuse practices as a case study, then evaluate the lesson’s resource alternatives using stated criteria.
Open on YouTube: How Japan saved its biggest city from collapse - Roman Krznaric (opens a new tab) ↗5 Human Impacts on the Environment: Crash Course Ecology #10
By CrashCourse
Identify resource-use impacts and tradeoffs; this broad context complements rather than replaces the numerical comparison.
Open on YouTube: 5 Human Impacts on the Environment: Crash Course Ecology #10 (opens a new tab) ↗What idea from the video helps you recommend a feasible strategy with two numerical comparisons and an explicit tradeoff? Identify one useful example and one limit of the video's model or explanation.
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Learning objective
Recommend a feasible strategy with two numerical comparisons and an explicit tradeoff.
Before you begin
- Compare costs, percentages and constraints.
Gather your materials
- Paper or notebook
- Pencil; calculator optional for numerical work; all task data supplied below
Language to know
- life-cycle boundary
- The stages included in an assessment of a product or process.
- reuse
- Using an item again without completely remaking its material.
- external effect
- A cost or benefit affecting people beyond an immediate transaction.
Understand the concept
Original fictional procurement brief: A school needs 100 durable desk frames. New-metal frames cost 10 tokens each and use 5 material units each; refurbished frames cost 7 and use 1 new unit each but need inspection capacity of 4 hours per 20 frames. Available inspection time is 16 hours. A mixed strategy is permitted. These figures cover purchase and new-material input only; they omit transport, service life, wages and other effects. Resource decisions require a transparent choice of boundaries and priorities.
Teach it step by step
- Read the brief and separate desired quantity, costs, material inputs and inspection constraint.
- Calculate the maximum refurbished count allowed by inspection time.
- Compare all-new and a feasible mixed strategy using the same boundary.
- Write a recommendation addressing an opposing concern, such as uncertain service life, without treating the lowest counted cost as the only value.
Make the thinking visible
Worked example or model response
16 hours permits 80 refurbished frames. A mix of 80 refurbished and 20 new costs 80(7)+20(10)=760 tokens and uses 80(1)+20(5)=180 new-material units. All-new costs 1,000 and uses 500 units. The comparison alone cannot establish lifetime environmental impact.
Guided practice
Together explain why 100 refurbished frames would exceed the supplied inspection capacity even though the purchase price is lower.
Independent practice
Write a proposal with the feasible quantities, cost and material comparison. Name two omitted life-cycle measures and explain a condition that could change the recommendation.
Quick assessment
Does reducing new-material input automatically prove every environmental outcome improves?
Answer key & assessment criteria
Answers and teaching guidance
- Guided: 100/20×4=20 hours, exceeding the available 16.
- Independent: Require a feasible strategy, accurate arithmetic and tradeoffs such as service life, transport or repair. Accept alternatives with explicit justified priorities.
- Quick check: No. Energy, transport, durability, pollution and other effects need their own evidence and stated boundaries.
Look for: Assess the stated objective using the concrete criteria and explanations in the answer key. Invite an alternative supported solution; distinguish a model’s prediction from an established observation.
Make it work for your learner
More support
Provide a 20-frame bundle table and compare one measure at a time.
Extension challenge
Assign plausible service-life scenarios and compare cost per frame-year, explaining the uncertainty of those assumptions.
Verified references · Selected contributions
Standards connections
Selected NGSS high school-band contribution; full performance requires additional evidence and instruction.
Subject-content standards
These records identify the part of a subject standard practiced here. Course placement is instructional guidance; the source’s category or band remains authoritative.
Contributes to NGSS performance expectation
HS-ESS3-2
NGSS · High school band
Evaluate resource-management solutions using costs, benefits and evidence.
Read the official performance expectation ↗This selected classroom resource comparison uses limited invented data. It does not establish full life-cycle impacts, actual procurement suitability or a universally preferred resource policy.
Verified 2026-11-04. Selected contribution, not full attainment.
Supporting literacy connections
These records apply to the specified reading, writing or communication task. They do not establish subject-content alignment.
Supporting Common Core literacy connection
RST.9-10.1
Common Core · Grades 9–10
Use precise textual details in scientific analysis.
Read the official standard ↗The activity explicitly analyzes the provided technical text, table or model. It contributes selected literacy practice rather than complete grade-band reading coverage or independent subject-content alignment.
Verified 2026-11-04. Selected contribution, not full attainment.