Supported HL focus. First assessment 2026; current SL/HL brief acquired. Remaining guide, assessment and practical requirements retain their recorded holds.
Prerequisites: read the stated quantities and units, use arithmetic and the model conditions below. Each lesson develops its own method before independent transfer.
These are original or explicitly fictional teaching examples, not actual measurements or completed assessed learner investigations.
9.2
Environmental law: rules, evidence and enforcement 执法
What would explain this observation?
Two catchments have the same discharge limit but different water quality. A legal rule can influence behaviour only through its coverage, implementation and enforcement.
Start with a prediction. State the quantities or features you would compare, then decide what evidence could distinguish two explanations.
Build the model
Environmental law defines obligations and permissions within a jurisdiction 管辖范围. A discharge permit may specify a concentration, a total load, monitoring and consequences of non-compliance. International agreements require implementation through institutions; signing an agreement alone does not show that an environmental outcome has improved.
enforcement: Implementation of rules through monitoring and consequences; jurisdiction: The geographical or institutional scope of an authority.
Choose evidence that can test it
Distinguish the legal instrument from the evidence about its effect. A concentration limit can be satisfied while total pollutant load rises if flow increases. Evaluate monitoring coverage, detection probability, incentives, access to justice and effects on different groups. An observed change after a policy is compatible with an effect but also with rainfall, industrial changes or other interventions.
Use an attributed historical or clearly fictional permit and paired monitoring data. Identify the regulated activity, responsible authority, geographical boundary and date. Compare upstream/downstream and before/after observations where available, document sampling gaps, and discuss whose evidence or costs are excluded. Do not present this classroom model as advice about current local law.
Work from known quantities
State the known values and their units. Choose the relation because its assumptions fit this case, then rearrange before substitution.
Known: a fictional permit caps discharge at 2 mg/L. A monitored discharge is 1.5 mg/L at 400 L/min. Load = concentration × flow = 600 mg/min. At the same concentration and 800 L/min the load is 1,200 mg/min. Both concentration observations satisfy the fictional cap, while the second transports twice the mass.
Example:
A discharge contains 1.2 mg/L at 500 L/min. Calculate transported mass per minute. Use the same sequence: known quantities → model → relation → substitution → unit and interpretation.
Check the conclusion and its limits
Compliance with one indicator does not prove ecological safety or fair enforcement. Compare actual outcomes with the policy objective and consider both administrative feasibility and affected communities.
Return to the original observation. Explain what the result supports, which conditions it assumes, and one way to test a competing explanation.
Warn:
A concentration-compliant discharge necessarily has a small total pollutant load. This claim is false: Compliance with one indicator does not prove ecological safety or fair enforcement. Compare actual outcomes with the policy objective and consider both administrative feasibility and affected communities.
Key:
Environmental law: rules, evidence and enforcement: Distinguish the legal instrument from the evidence about its effect. A concentration limit can be satisfied while total pollutant load rises if flow increases. Evaluate monitoring coverage, detection probability, incentives, access to justice and effects on different groups. An observed change after a policy is compatible with an effect but also with rainfall, industrial changes or other interventions.
