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Earth & Space Science

Study Guide

Earth and space science makes up about 20% of the GED Science test. You need to understand weather, climate change, Earth's structure, plate tectonics, and basic astronomy.

1Weather vs. Climate

Weather is the short-term condition of the atmosphere (today's temperature, rain, wind). Climate is the average weather pattern in an area over a long period (30+ years).

Examples:

•Weather: 'It's raining today in Miami'
•Climate: 'Miami has a tropical climate with hot, humid summers'
•Climate change refers to long-term shifts in global temperatures and weather patterns
2Plate Tectonics

Earth's crust is broken into plates that float on the mantle. Plate movement causes earthquakes, volcanoes, and mountain formation. Plates can converge (push together), diverge (pull apart), or slide past each other.

Examples:

•Convergent boundary: plates push together → mountains or subduction zones
•Divergent boundary: plates pull apart → rift valleys, mid-ocean ridges
•Transform boundary: plates slide past each other → earthquakes (San Andreas Fault)
3The Solar System

Our solar system has 8 planets orbiting the Sun. Inner planets (Mercury, Venus, Earth, Mars) are rocky. Outer planets (Jupiter, Saturn, Uranus, Neptune) are gas/ice giants.

Examples:

•Earth's rotation (spinning) causes day and night (24 hours)
•Earth's revolution (orbiting the Sun) takes 365.25 days (one year)
•Seasons are caused by Earth's tilted axis, NOT distance from the Sun
•The Moon's gravity causes ocean tides on Earth
4Rock Cycle

Rocks are constantly changing between three types: igneous (cooled magma/lava), sedimentary (compressed layers of sediment), and metamorphic (changed by heat and pressure).

Examples:

•Igneous: formed when magma or lava cools (granite, basalt)
•Sedimentary: formed from compressed sediments (sandstone, limestone). Often contain fossils.
•Metamorphic: existing rock changed by heat/pressure (marble from limestone)
Test-Taking Tips
Don't confuse weather (short-term) with climate (long-term average).
Seasons are caused by Earth's 23.5° tilt, NOT by distance from the Sun.
GED questions about Earth science often include maps or diagrams — read them carefully.
Know the difference between rotation (spinning on axis = day/night) and revolution (orbiting Sun = year).