Science and Environmental Awareness
The Science and Environmental Awareness section covers basic biology, matter and energy, earth and space, and - heavily - the atoll environment: how atolls form, where fresh water comes from, what reefs and lagoons are like, and how climate change, waste and fishing affect them.
Core ideas
- Atolls are rings of coral reef around a lagoon, formed as a volcanic island subsides while the reef grows upward.
- Fresh water on an atoll is a thin lens of rain water floating on denser seawater inside porous coral rock. It is recharged only by rain, is a few metres thick, and is easily polluted or over-pumped.
- Coral is an animal living with microscopic algae; when water stays too warm it loses the algae and turns white (bleaching).
- Weather is today's condition; climate is the long-term pattern. King tides, storm surges and La Niña droughts are separate events that can make sea-level rise worse.
- Energy: most electricity comes from imported diesel, so solar systems and efficient appliances cut both cost and emissions.
- Fair tests change one variable at a time and keep everything else the same.
Worked example
A village installs a large new pump on one well, and within months the water tastes salty. Reasoning: The lens is thin and floats on seawater, so heavy pumping at one point lowers the fresh water and draws seawater upward. The salty taste is not evidence that the rain stopped: it points to over-abstraction at a single well. To be sure, you would check rainfall records to rule out drought and compare salinity tests taken before and after the pump. The remedy is to spread abstraction across wells, protect the wellhead from animals, and harvest rain.
Traps that cost marks
Blaming sea-level rise for a single king tide; thinking boiling removes salt from water; calling coral a rock or a plant; confusing the lagoon side with the ocean side when locating a well.