Earth and Space Science
This domain tests Earth materials and processes, plate tectonics, weather and climate, and Earth-Moon-Sun relationships. Expect questions that require interpreting sequences, distinguishing similar processes, and correcting common misconceptions about seasons and moon phases.
Earth materials and processes
- Earth's layers are crust, mantle, liquid outer core, and solid inner core.
- Divergent boundaries move plates apart; convergent boundaries move them together and can produce subduction; transform boundaries slide past one another.
- The rock cycle includes igneous rock (cooling magma or lava), sedimentary rock (compaction and cementation of sediments), and metamorphic rock (heat and pressure).
- Weathering breaks rock in place; erosion transports sediment.
Earth, Moon, and Sun
- Seasons result from axial tilt changing sunlight angle and day length, not from distance to the Sun.
- Moon phases result from the Moon's orbit changing the sunlit portion visible from Earth; Earth's shadow causes eclipses, not ordinary phases.
- The water cycle includes evaporation, condensation, precipitation, runoff, and infiltration.
Worked example
A cliff shows horizontal sedimentary layers: sandstone on the bottom, shale above it, and limestone at the top, with a trilobite fossil in the shale. Which layer is oldest? Using superposition, the bottom sandstone is oldest and the limestone is youngest, assuming the layers have not been overturned. The trilobite is useful for relative dating as an index fossil, but it does not by itself give an absolute age. Reasoning: in undisturbed sedimentary sequences, older layers lie below younger ones.
Traps that cost marks
- Explaining summer as Earth being closer to the Sun.
- Confusing rotation (day) with revolution (year).
- Calling weather climate; climate is long-term atmospheric pattern.
- Confusing weathering with erosion.
- Claiming moon phases are caused by Earth's shadow.