Environmental Science

What this covers

• Biogeochemical cycles (carbon, nitrogen, phosphorus, hydrologic) — identifying reservoirs, fluxes, and exactly where human activity such as Haber-Bosch fertiliser or fossil fuel combustion alters a flow
• Population math: exponential and logistic growth, rule of 70 doubling time, calculating crude birth and death rates, and interpreting age-structure diagrams and total fertility rate against the demographic transition model
• Energy flow and the 10% rule — trophic pyramids, gross versus net primary productivity, and calculating energy available at each level
• Quantitative problem solving without a calculator: dimensional analysis, scientific notation, percent change, per-capita rates, and energy unit conversions typical of free-response question sets
• Pollution mechanisms — tropospheric ozone and photochemical smog, acid deposition, eutrophication and hypoxia, BOD, thermal pollution, and the difference between point and nonpoint sources
• Energy resources and climate: comparing coal, natural gas, nuclear, hydro, wind and solar on emissions, land use, capacity factor and cost; plus the greenhouse effect, feedback loops, and ocean acidification chemistry
• Environmental legislation and policy tools (Clean Air Act, Clean Water Act, CITES, Montreal and Kyoto/Paris) and how cap-and-trade or a carbon tax actually changes behaviour

Where learners get stuck

Merging stratospheric ozone depletion with the greenhouse effect into one 'hole causes warming' story

Both are global atmospheric problems taught close together and both involve gases released by industry, so students blend CFCs, UV radiation and infrared trapping. The mechanisms, altitudes and treaties are entirely separate, and exam questions routinely test whether a student can keep them apart.

Treating 'renewable' as a synonym for 'clean' or 'sustainable'

The vocabulary invites it. Students then cannot explain why biomass burning releases particulates, why hydroelectric dams flood habitat and release methane, or why a resource can be renewable and still be overharvested if the extraction rate exceeds the replenishment rate.

Reading an age-structure diagram as a picture of current population size rather than future momentum

The pyramid shape is visual and intuitive, so students say 'this country is crowded' instead of 'this country will keep growing for decades even if fertility drops to replacement level today.' Population momentum is abstract and requires thinking one generation ahead.

Reversing the energy flow rule and assuming top predators hold the most energy because they are largest

Biomass and body size are conflated with energy. Once students practise multiplying by 0.1 at each trophic step and stating where the other 90% went (respiration, heat, undigested matter), the pyramid logic holds.

What a session looks like

Sessions run as spoken back-and-forth with Evelyn. A typical hour might start with you explaining a cycle or a pollution mechanism out loud, then move into worked calculations — Evelyn reads out the data (a fertiliser application rate, a power plant's output in megawatts, a fish population census) and you set up the dimensional analysis verbally, stating units at each step, which is exactly what earns credit on free-response answers. Evelyn will push for the second half of an answer that students usually drop: not just naming a solution but justifying it, or not just giving a number but stating the units and what it means. Diagrams and graphs you are working from can be described aloud, and Evelyn will walk you through interpreting them.

Helpful to know first

• Algebra I: solving for a variable, working with percentages and ratios, and reading linear and exponential graphs
• Comfort with scientific notation and unit conversion, since much of the course's maths is multiplying and dividing large numbers by hand
• Introductory biology: photosynthesis and cellular respiration equations, food webs, and basic cell and organism vocabulary
• Introductory chemistry: atoms and molecules, the pH scale, combustion products, and what a chemical equation represents
• Basic geography — continents, major biomes, and where oceans and prevailing winds are

Questions

Is environmental science easier than chemistry or biology?

The reading is more accessible, but the course is broad rather than shallow — it draws on chemistry, biology, earth science, statistics and economics in the same unit. Students who struggle usually do so on the quantitative free-response questions and on writing precise cause-and-effect explanations, not on the content itself.

How much maths is in this course?

Enough that it decides grades. Expect percent change, doubling time, per-capita rates, half-lives, energy unit conversions and trophic energy calculations, typically done without a calculator, with units required at every step. Sessions spend substantial time on setting these up correctly.

My child took the course but the free-response answers keep losing marks. What is going wrong?

Usually the answers are too short or name a term without explaining the mechanism. Questions asking to 'describe' or 'justify' require a stated cause and effect, and 'propose a solution' requires the solution plus why it addresses that specific problem. Practising this out loud surfaces the gap quickly.

Can this help prepare for an end-of-year exam?

Sessions can work through past-style question sets, timed calculation practice and content review by unit. This is independent tutoring with no affiliation to any examining body, so we work from the published course topics and released practice materials.

How long does it take to review the whole course?

Covering all nine standard units at a reviewing pace typically takes ten to fifteen sessions. Students targeting specific weak areas — commonly population maths, energy calculations, or the nitrogen and phosphorus cycles — often need only three or four.