Engineer for People and the Planet

50-60 minutes

• Set up as many of the three stations as you can: filter (cups, sand, gravel, cotton, cloudy water), flood barrier (tray, water, a small paper house), and product redesign (cardboard, tape, an everyday object).
• Make cloudy 'dirty' water ahead of time by stirring a little dirt or pepper into a jug - nothing unsafe.
• Keep a tray, bucket, or sink area nearby to catch water and spills.

• Pre-cut plastic bottles into filter housings if you are using bottles.
• Pour equal cups of cloudy water in advance so every team tests with the same starting water.

• Filtered water is for looking at only - students must NOT taste or drink any water in this lesson. Say it aloud and post it at the station.
• Wipe spills up right away to prevent slips, and keep all water away from devices.

• Explain that engineers design for a specific user and a real problem.
• Name a constraint and a tradeoff in their own design.
• Choose a material based on how it behaves - soaks up, blocks, or filters water.

• Jumping to building before naming the user and the problem.
• Filter layers packed too loosely, so cloudy water runs straight through.
• A flood barrier with gaps at the edges where water sneaks past.

• "Who is this for, and what problem are you solving for them?"
• "What tradeoff did you make - what got worse when something got better?"
• "Which material worked best, and why do you think that is?"
• "What would a real user still struggle with?"

Assign one path - usually the water filter - to the whole group, and give them the user and problem already named.

Add a second goal, like a filter that is also fast or a barrier that can be reused, which forces a clear tradeoff.

• Pour used water into a sink or bucket, not the trash; wring out and bin any soaked materials.
• Dry and save cups, trays, and cardboard that are still usable.