Earth and Space Science: Earth Systems, Rocks, and Sky Patterns
What to know
Earth has a layered structure - crust, mantle, outer core, inner core - and its crust is broken into plates that move slowly over the mantle. Plate boundaries produce earthquakes, volcanoes, and mountain ranges, and the fossil and rock record supports continental drift. Rocks fall into three families: igneous (cooled magma or lava), sedimentary (compacted layers, often containing fossils), and metamorphic (changed by heat and pressure). The rock cycle links all three.
Weathering breaks rock down in place, erosion carries the pieces away, and deposition drops them. The water cycle moves water through evaporation, condensation, precipitation, and runoff, and the Sun drives it. Weather is the short-term state of the atmosphere; climate is the long-term pattern.
In space, Earth rotates on its axis once a day, causing day and night, and revolves around the Sun once a year. Seasons come from the tilt of Earth's axis, not from distance from the Sun. Moon phases result from the changing angle between Earth, the Moon, and the Sun as the Moon orbits; the Moon does not glow on its own. Eclipses occur only when the three bodies line up.
Traps to watch
The most common error is explaining summer by closeness to the Sun. Another is confusing rotation with revolution, or claiming the Moon's phases are caused by Earth's shadow. Remember that the Sun is a star and that planets do not produce their own light.
Worked example
When the Northern Hemisphere tilts toward the Sun, it receives more direct sunlight and longer days, so it is summer there while the Southern Hemisphere has winter. Rule of thumb: tilt explains seasons; alignment and shadow explain eclipses, not phases.