Learn Balance flows over time and inspect the trade-offs hidden by totals.
Start with everyday situations, predict an outcome, and test your ideas. You need basic arithmetic, percentages and graph reading; explanations introduce additional ideas where needed. No coding or account is required. Every investigation has school, college and workplace extensions—you can choose any of them.
Account for timing, service delivered, accumulated stocks and competing resource objectives when evaluating an environmental intervention.
Open any topic directly. Review functions and graphs whenever useful.
The original two-investigation starter remains available. Choosing the full course adds its published lessons to your selected scope; your earlier work stays saved. Skipping does not count as completion or understanding.
Free exploration: no completion scope selected yet. Project reports and independent evidence are tracked separately.
Choose a unit, then open a lesson on its own page. This outline lists the sequence; it does not combine the full lessons into one page.
Explain storage limits, seasonal replenishment and the difference between emissions and accumulated burden.
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Why can equal daily generation and demand still require grid energy?
Original synthetic six-period energy schedule in kWh: generation [0, 2, 8, 4, 0, 0] and demand [2, 2, 2, 2, 4, 2]. Storage starts empty.
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How long can stored water conceal demand greater than replenishment?
Original synthetic reservoir: initial stock 60 units, capacity 100, twelve months; recharge is halved in months five through eight.
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How do accumulation and removal affect intervention outcomes?
Original synthetic scenario. A fictional pollutant starts at 20 units. Each period removes a fraction of the starting stock, then adds new emissions. A policy reduces emissions from a chosen period.
Account for occupancy, whole trips, upfront impact and changes in use before claiming an improvement.
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How do occupancy and whole-vehicle trips change an energy comparison?
Original synthetic scenario. A fictional car uses 2 energy units per distance unit; a bus uses 10. All travelers must be transported and each vehicle travels the full distance.
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When does lower operating impact offset manufacturing and increased use?
Original synthetic scenario. An existing device uses 40 impact units per period. A replacement has an upfront impact, lower impact per use, and a possible increase in use.
Compare land and water allocations with explicit objectives and drought stress tests.
○ Not marked complete · Included · Practice check available
Can a high-output land plan still work when water falls short?
Original synthetic scenario. Ten divisible plots can be habitat, dry farmland or irrigated farmland. Irrigation uses five water units per plot; food and a habitat index use explicit synthetic rules.
Choose an energy, water, transport or land-use decision. Compare alternatives on an explicit service and time basis, account for resources or impact, and test an adverse scenario. Use captures from at least two experiments. All supplied rates and indices are synthetic; a real recommendation needs appropriate local evidence.
Save a report, compare captured evidence, and attempt three new cases. A completed report records submitted work; the rubric supports a separate human review of its quality.
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