Earth, Space and Natural Cycles
Earth, Space and Natural Cycles tests Earth systems, rocks and tectonics, weathering and erosion, the water cycle, and explanations for seasons, moon phases, and eclipses. Questions often ask you to choose the correct cause for an everyday sky or landscape observation.
Core concepts
- Earth spheres are the geosphere, hydrosphere, atmosphere, and biosphere; they exchange matter and energy.
- The rock cycle transforms igneous, sedimentary, and metamorphic rocks through melting, cooling, weathering, deposition, compaction, heat, and pressure.
- Weathering breaks rock; erosion transports sediment; deposition lays it down.
- The water cycle includes evaporation, condensation, precipitation, runoff, and infiltration.
- Seasons result from Earth axial tilt, not distance from the Sun.
- Moon phases result from changing angles among Earth, Moon, and Sun; eclipses require precise alignment.
Worked example
Why is July warmer in the Northern Hemisphere? Earth axis tilts about 23.5 degrees. In July, the Northern Hemisphere leans toward the Sun, so sunlight strikes more directly and days are longer. That hemisphere receives more concentrated energy per area. Distance cannot explain seasons because both hemispheres would warm together, and Earth is actually farthest from the Sun in July.
Traps that cost marks
Saying seasons are caused by distance; confusing rotation and revolution; thinking phases are Earth shadow; confusing waxing and waning; saying erosion and weathering are the same; forgetting eclipses need alignment.