Lesson 4: Controlled Intervention and System Monitoring

Did the intervention reduce the limiting factor?
Are ammonia and nitrite stable over time?
Did nitrate accumulation change?
Did algae decrease or plateau?
Is stability temporary or sustained?

Trend analysis
Stability
Plateau
Intervention effect
Sustained balance
Short term correction
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, Constructing Explanations

Crosscutting Concept, Stability and Change
Crosscutting Concept, Cause and Effect

Students implement the selected intervention.

They monitor:

Ammonia
Nitrite
Nitrate
Water clarity
Algae presence

Students graph parameter trends before and after intervention.

They evaluate:

Did ammonia remain low?
Did nitrate stabilize?
Did algae visibly decline?
Was the improvement consistent across multiple days?

Students refine their system model to include:

Input versus capacity
Biological load
Sustained stability versus temporary correction

The purpose is to reinforce that stability is dynamic and must be maintained.

DOK 2
Record and interpret parameter data.

DOK 3
Evaluate effectiveness of intervention using evidence and trend analysis.

Approaches DOK 4 when students justify long term sustainability and propose further adjustments.

Engineers test solutions over time before scaling them.
Environmental remediation projects require monitoring before declaring success.
Aquaculture systems require continuous data analysis to maintain livestock health.

If the system looks clear, it is fully stable.
If ammonia drops once, the problem is solved permanently.
Interventions have immediate and complete effects.
Short term improvement guarantees long term stability.

https://docs.google.com/document/d/1siFIsOAs45CxuUlyJt9dNRdT70eTva14fJMeE1qXHPk/edit?usp=sharing%20

Intervention Evaluation Reflection

Students submit a written evaluation explaining:

Whether the intervention improved stability.
What evidence supports their claim.
Whether stability appears sustainable.
What adjustment might be necessary next.