Whole Earth Curriculum WEC

Lesson 03 — Design Trade-offs: Cost, Safety, Access, Environment

Learners explain how **design decisions involve trade-offs among cost, safety, access, and the environment**, using the real example of lighting a home without grid electricity — a kerosene lamp versus a solar lamp. They see that no design is best at everything, and that a good design names what it is trading away.

D10 P4: Contextual & Ecological Awareness D10.S1 50 minutes Draft

Objectives

Essential question

How do design decisions involve trade-offs among cost, safety, access, and the environment?

trade-offcostsafetyaccessenvironmentdesign

Materials

Standard materials

Low-tech / no-cost

Enriched / lab & device

Works in different contexts

A diagram with a design choice at the center and four labeled corners — cost, safety, access, environment — with a kerosene lamp and a solar lamp on either side, showing how improving one corner often costs another
A diagram with a design choice at the center and four labeled corners — cost, safety, access, environment — with a kerosene lamp and a solar lamp on either side, showing how improving one corner often costs another

Lesson 3 — Design Trade-offs: Cost, Safety, Access, Environment

Summary

Learners explain how design decisions involve trade-offs among cost, safety, access, and the environment, using the real example of lighting a home without grid electricity — a kerosene lamp versus a solar lamp. They see that no design is best at everything, and that a good design names what it is trading away.

Objectives

  • Explain how design decisions involve trade-offs among cost, safety, access, and the environment, using a real example. (D10.S1.08.02)

Connection

When you choose between two ways to do one job — walk or ride, paper or screen — you are doing what every designer does: trading one thing for another. The walk is slower but cleaner and free; the ride is faster but costs money and fuel. Designers face the same four questions for every object: How much does it cost? Is it safe? Who can reach it? What does it do to the Earth? Today you learn to name the trade that lives inside every design.

Materials

  • Trade-off sheet
  • Case cards

Preparation

  • Copy the sheet and case cards.
  • Retrieval: from Lesson 2, recall the benefits-and-harms skill; today we look inside the design behind those benefits and harms.

Facilitator note

This lesson is written to the learner (“you”). The idea to land: every design trades one good for another; there is no perfect design, only designs that are honest about what they trade. The worked example: lighting a home without grid electricity. A kerosene lamp is cheap to buy — low upfront cost — but it is a fire hazard (unsafe), its smoke harms health (WHO household air pollution, S-219), and burning kerosene pollutes the environment and emits carbon. A solar lamp is clean and safe — better on safety and environment — but it costs more upfront, which limits access for people who cannot afford it, and it depends on sunlight and a battery that will one day be waste. So the trade-off is real: low cost now versus safety and a clean environment, with access caught in the middle. The egalitarian lens: “access” is the corner that asks who is left out — a lamp that costs too much stays out of the hands that need it most. The ethics lens: a designer who ignores safety or the environment to save cost is making a moral choice, not just a technical one. The global lens: this exact trade-off is being made right now in homes from Nairobi to the Himalayas, where off-grid solar is growing fast. The technology & environment lens: the “environment” corner is not optional decoration — it is one of the four things every real design must weigh (S-095, S-371). Keep the example factual; let learners argue which corner matters most and why, without forcing a single answer (philosophy §11).

Procedure

  1. Recall (5 min). From Lesson 2: the same technology helps some and harms others. Today we ask a deeper question: why does a technology land that way? Because of the design.
  2. Meet the four corners (10 min). A designer balances four things: cost (what it takes to make and buy), safety (does it hurt anyone?), access (who can actually reach and use it?), and the environment (what does it do to the living Earth?). Say each in your own words.
  3. Meet the case (10 min). Read the case cards: two ways to light a home without grid electricity — a kerosene lamp and a solar lamp. For each, sort the facts into the four corners.
  4. Find the trade (15 min). Worked example: the kerosene lamp — low cost, but unsafe (fire) and bad for health and environment (smoke, carbon). Now do the solar lamp: safe and clean, but higher cost and so less access. Write the trade in one sentence: “You can have ___ , but it costs ___ .”
  5. Weigh (7 min). If you had to choose for a family with little money and no grid, which lamp would you design toward, and which corner would you protect most? Why?
  6. Close (3 min). There is no perfect design — only designs that are honest about what they trade.

Differentiation

  • Support: Provide the trade-off sentence starter and ask the learner to fill in two corners only.
  • Extension: Choose a second design decision and map its four trade-offs, then defend which corner matters most in that case.

Assessment

  • Formative (observation): Can the learner name the four corners and state one real trade-off in one sentence?
  • Portfolio artifact: The completed trade-off sheet, kept in the portfolio.

Home connection

Look at one thing your household uses every day and ask: what trade-off did its designers make among cost, safety, access, and the environment? Discuss one.

Resources