Lesson 2: Build, Monitor, Evaluate, and Redesign

Does our system function as designed?
Is it biologically ready to support fish?
How does ammonia respond after fish introduction?
What caused instability if it occurred?
How would we redesign this system for improved performance?

Implementation
Readiness criteria
Cycling
Ammonia spike
Stress indicator
Iteration
Root cause
Redesign
System stability
Feedback loop

HS-ETS1-3
Evaluate a solution to a complex real-world problem based on prioritized criteria and trade-offs.

HS-LS2-4
Use mathematical representations to support claims for cycling of matter.

Science and Engineering Practice – Planning and Carrying Out Investigations
Science and Engineering Practice – Analyzing and Interpreting Data
Science and Engineering Practice – Engaging in Argument from Evidence

Crosscutting Concept – Stability and Change
Crosscutting Concept – Cause and Effect

Students analyze cause-and-effect relationships.
Students evaluate system performance using evidence.
Students defend redesign decisions logically and clearly.

Day 7 – Construction

Students build according to blueprint and document deviations.

Documentation includes:

What changed
Why it changed
How it affects nitrogen cycle

Day 8 – Flow Testing and Plant Establishment

System runs without fish.

Students test:

Flow consistency
Water pooling
Initial parameter baseline

Day 9 – Biological Monitoring

Students test:

Ammonia
Nitrite
Nitrate

They evaluate readiness trajectory.

Day 10 – Fish Readiness Defense

Groups must justify fish introduction using:

Stable ammonia
Low nitrite
Functional flow
Established plants

Teacher approves or delays.

Day 11 – Post-Fish Monitoring

Students measure ammonia response and fish behavior.

They compare predicted versus actual parameter shifts.

Day 12 – Performance and Redesign Analysis

All groups complete structured evaluation.

If system was stable:
Explain why it worked.

If instability occurred:
Identify root cause.
Propose redesign.
Explain how redesign addresses failure.

Failure earns credit if reasoning is biologically sound.

DOK Level

DOK 2 – Monitor and interpret parameter data.
DOK 3 – Evaluate system effectiveness under biological load.
Approaches DOK 4 – Diagnose failure and propose justified redesign.

Primary Level: DOK 3 moving toward DOK 4 during redesign analysis.

Prototype testing is essential before scaling food systems.
Small urban food systems require careful monitoring.
Failure analysis drives improvement in engineering and agriculture.

Students experience authentic iterative design.

If fish survive one day, system is stable.
Failure equals bad design rather than learning opportunity.
Clear water equals balanced system.
Plants immediately correct ammonia spikes.

Assign structured build roles.
Provide readiness checklist.
Offer reflection graphic organizer.
Allow verbal explanation before written redesign.
Challenge advanced students to quantify percent parameter change after fish introduction.

Group Build Evaluation

Evaluated on:

Alignment between blueprint and implementation
Biological reasoning during readiness decision
Quality of documentation
Problem-solving during instability

Individual Reflection #2

Students must include:

Performance evaluation using evidence
One success and one limitation
Root cause analysis if failure occurred
Proposed redesign and biological justification
Connection to nitrogen cycle

Grading prioritizes reasoning depth, evidence use, and systems thinking over perfect biological outcome.