HS-ESS3-2: Weighing Costs and Benefits of Resource Use
Also called NGSS HS-ESS3-2 · Topic: Human Sustainability · Earth and Space Science
The Official Wording
Evaluate competing design solutions for developing, managing, and utilizing energy and mineral resources based on cost-benefit ratios.
Clarification statement: Emphasis is on the conservation, recycling, and reuse of resources (such as minerals and metals) where possible, and on minimizing impacts where it is not. Examples include developing best practices for agricultural soil use, mining (for coal, tar sands, and oil shales), and pumping (for petroleum and natural gas). Science knowledge indicates what can happen in natural systems—not what should happen.
NGSS Lead States, 2013 · Read it on nextgenscience.org · checked October 15, 2026
What HS-ESS3-2 Means in Plain English
Students compare rival ways to get and use energy or mineral resources, such as mining new ore versus recycling metal, or two methods of drilling for gas. For each option they list costs and benefits, put numbers on them where possible, and argue for the best balance.
The focus is on conserving, recycling and reusing materials, and on shrinking the damage when extraction cannot be avoided. Science shows what will likely happen, while people decide what should happen. It builds on HS-ESS3-1 and pairs with the engineering practice in HS-ETS1-3.
HS-ESS3-2 I Can Statements
- I can list the costs and benefits of a resource choice.
- I can compare two designs using a cost-benefit ratio.
- I can explain why recycling metal often beats mining new ore.
HS-ESS3-2 Worked Example
A design comparison a class can run on where a town's aluminum cans should come from.
Is it better to make new aluminum cans from mined bauxite or from recycled cans?
Set It Up: A decision matrix on chart paper, published energy figures for new and recycled aluminum, and a bag of crushed cans weighed on a kitchen scale.
- Define the problem and the criteria: energy, cost, land disturbed and waste.Four criteria, each scored 1 to 5
- Look up the energy each route needs.Recycling uses about 95% less energy
- Score mining and recycling on each criterion and compare benefits to costs.Recycling wins energy, land and waste
- Name the limit: recycled cans alone cannot cover rising demand.Some new metal still needed
- Improve the plan, then rescore it.Higher can return rate plus cleaner mining
Recycling gives far more benefit for its cost, but a mixed plan that raises recycling and reduces the harm of new mining scores best.
Why it works: Melting scrap skips the energy-hungry steps of refining ore and splitting aluminum from oxygen, so it needs only a small share of the energy.
Common Mistakes with HS-ESS3-2
Counting only money
“Mining is cheaper per ton, so mining wins.”
Try this: Count energy, land damage, water use and waste as costs too, and score them alongside the price before comparing options.
All or nothing
“Just recycle everything and stop all mining.”
Try this: Check whether one option can meet demand alone. Often the best plan mixes options and reduces the harm of each.
Science as the verdict
“The data proves we should ban new mines.”
Try this: Data shows what each option will likely do. Deciding what should happen also weighs values, jobs and fairness, which people must debate.
Where HS-ESS3-2 Fits
Practice HS-ESS3-2
Quick Check
- Why does recycled aluminum need so much less energy than new aluminum?
- A mine creates jobs but pollutes a river. How does a cost-benefit comparison handle that?
- Why might the best plan still include some new mining?