Unit 01 · The Ocean Environment
This unit builds the stage every other unit stands on: the physical ocean. You map its zones — the sunlit, twilight, and midnight layers, and the intertidal-to-abyssal floor beneath them — then learn why seawater behaves as it does: what salinity is and how it sets density, how temperature, pressure, and light change as you descend, and how wind and density drive the currents that move heat and nutrients around the planet. Mastery means you can read the ocean as a system of measurable properties, not a flat blue map.
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| Ocean zones & structure | Pictures the ocean as one uniform body of water. | Names the sunlit, twilight, and midnight zones but confuses pelagic and benthic, or open water with the floor. | Maps the vertical zones by light and depth, distinguishes pelagic from benthic and intertidal from abyssal, and explains what lives where and why. |
| Salinity & seawater properties | Thinks seawater is just “water with salt.” | Defines salinity but cannot connect it to density or measurement. | Explains salinity in practical terms, relates it to density and stratification, and reads a hydrometer or refractometer to measure it. |
| Depth: temperature, pressure & light | Assumes the ocean is the same top to bottom. | Knows conditions change with depth but not the pattern. | Describes the thermocline, the roughly one-atmosphere-per-ten-metres pressure rise, and how light attenuates — and predicts conditions at a given depth. |
| Currents & circulation | Believes ocean water sits still. | Names surface currents but not what drives them. | Distinguishes wind-driven surface currents from density-driven thermohaline circulation, explains upwelling, and links currents to heat and nutrient transport. |
| Lab technique (water-property investigation) | Skips readings or records them without units. | Takes measurements but is careless with the salinity or temperature tools. | Runs a clean ocean-zone & water-property investigation — salinity, temperature, and density measured, recorded with units, and interpreted. |
| Integration (cross-domain) | Treats the science as isolated facts; makes no cross-domain connection. | Names a link to history, reading, or writing but cannot defend why it matters. | Connects the unit to its anchor across History · Reading · Writing (plus chosen electives) and defends why the connection matters. |
“Below about 200 metres the light runs out, so there’s no photosynthesis — that’s why the twilight zone lives on what sinks from above. Pressure climbs roughly one atmosphere every ten metres, and the cold, salty deep water is denser, so it sinks and drives the thermohaline circulation. I measured the surface salinity at 34 with the refractometer.”
“It’s deeper so it’s… colder? And the ocean moves because of… waves, I think. Salt is just salt.”
You demonstrate this unit through the ocean-zone & water-property investigation plus short oral checks where you reason from measurements aloud — not a multiple-choice test. A criterion counts as mastered only when you can both take the readings and explain the ocean physics behind them. Mastery is demonstrated, not awarded.
A 5-page clipboard packet — unit overview, key terms, the mastery rubric, anchor examples, and a score sheet you can print and grade against.