Solutions That Reduce Impact
Aligned to HS-ESS3-4 — Next Generation Science Standards.
What this lesson teaches
Engineers design and refine technologies to lessen human impact on natural systems. A good solution is tested against criteria like effectiveness, cost, and unintended side effects, then improved based on real-world data.
Worked examples
Example 1
To cut water pollution, a city builds a wetland to filter farm runoff before it reaches a river. Monitoring shows nitrogen levels drop, but the wetland floods nearby fields, so engineers refine the design by adding a controlled overflow channel.
Example 2
Monitoring has to begin before the change. Without a baseline you cannot tell whether the wetland worked or the rain simply eased.
Example 3
A solution that creates a new problem has not failed — it has moved. The overflow channel is the second iteration, not an admission of error.
Practice questions
- Observe: A solution that fixes one problem sometimes creates another. Why does testing a design against multiple criteria matter?
- Model: Propose a technology to reduce one human impact, such as plastic waste, and list the criteria you would use to judge it.
- Explain: A solar farm reduces emissions but disrupts desert habitat. Refine the design to lower its ecological impact and justify your changes.
Watch the lesson
Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.
▶ Watch this lessonEn español
Soluciones que reducen el impacto
Los ingenieros diseñan y mejoran tecnologías para reducir el impacto humano en los sistemas naturales. Una buena solución se evalúa con criterios como eficacia, costo y efectos secundarios no deseados, y luego se mejora con datos del mundo real.
Ejemplo 1: Para reducir la contaminación del agua, una ciudad construye un humedal que filtra los escurrimientos agrícolas antes de que lleguen a un río. El monitoreo muestra que los niveles de nitrógeno bajan, pero el humedal inunda campos cercanos, así que los ingenieros mejoran el diseño agregando un canal de desbordamiento controlado.
Ejemplo 2: El monitoreo tiene que empezar antes del cambio. Sin una línea base no puedes saber si el humedal funcionó o simplemente bajó la lluvia.
Ejemplo 3: Una solución que crea un problema nuevo no fracasó — se movió. El canal de desfogue es la segunda iteración, no una admisión de error.
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