Earth and Space Science - Geology, Weather, Astronomy, Earth's Interior and History
This domain tests Earth's layered interior, plate tectonics, rocks and fossils, weather systems, and astronomical cycles. Expect questions interpreting seismic data, rock sequences, weather maps, and diagrams of the Sun–Earth–Moon system.
Earth's interior and geology
Earth has a crust, mantle, liquid outer core, and solid inner core. P waves travel through solids and liquids; S waves cannot pass through liquids, revealing the liquid outer core. Earthquakes have a focus underground and an epicenter at the surface. Plate boundaries produce earthquakes, volcanoes, and mountain belts. The rock cycle links igneous, sedimentary, and metamorphic rocks. In undisturbed strata, lower layers are older; fossils can indicate relative age.
Weather
The atmosphere has pressure that decreases with altitude. Wind blows from high to low pressure. High pressure generally brings sinking air and fair weather; low pressure brings rising air, clouds, and rain. Fronts mark boundaries between air masses. The water cycle moves water through evaporation, condensation, precipitation, and runoff.
Astronomy
Earth's rotation causes day and night; revolution and axial tilt cause seasons. The Moon's phases depend on the Sun–Earth–Moon angle, not Earth's shadow. A solar eclipse occurs at new Moon; a lunar eclipse at full Moon. The solar system has eight planets; stars produce their own light.
Worked example
A seismic station is 36 km from an epicenter. P waves travel at 6 km/s and S waves at 3 km/s. P arrival time = 36 ÷ 6 = 6 s; S arrival time = 36 ÷ 3 = 12 s. The difference is 6 s. A more distant station has a larger difference, which helps locate the epicenter.
Traps
Seasons are caused by axial tilt, not distance from the Sun. Moon phases are not caused by Earth's shadow. P waves are faster than S waves. High pressure usually means fair weather. Epicenter is not the same as focus. Undisturbed strata are older at the bottom, but overturned strata can reverse this.