Grade 12 · Science
Track a simplified environmental stock practice
Use a stated stock-and-flow model to calculate change while distinguishing model assumptions from real-world forecasts.
Opening your practice adventure…
Try a sample
A model predicts constant outflow, but observations show outflow rises as the stock grows. What should be reconsidered?
- Whether observations can ever inform a model.
- Whether changing evidence must be ignored.
- Only the model diagram's color.
- The constant-outflow assumption.
See the answer & why
The constant-outflow assumption.
The observations challenge a specific assumption used in the projection.
A little hint: Ending stock = starting stock + inputs − outputs; keep all quantities in the same units and time interval.
A teaching tip
Ending stock = starting stock + inputs − outputs; keep all quantities in the same units and time interval.