Earth Science

Earth as a set of linked systems, and the maps that say where a place is and how high it stands.

1. Earth's Four Spheres
2. Latitude and Longitude
3. Reading Topographic Maps

How Earth's spin and orbit, and the Moon's orbit, make days, seasons, phases, eclipses and tides.

1. Earth's Spin: Day and Night
2. Why We Have Seasons
3. Phases of the Moon
4. Solar and Lunar Eclipses
5. Gravity and Orbits
6. Tides

What orbits the Sun, how big and far apart things are, and where the Sun sits among the stars and galaxies.

1. Planets, Moons and Small Bodies
2. The Scale of the Solar System
3. Light-Years, Stars and Galaxies

Density, Earth's layers, and the slow flow of hot rock that moves the surface.

1. Density
2. Earth's Layers
3. Lithosphere and Asthenosphere
4. Convection

What minerals are, how to tell them apart, and how the three rock families form and turn into one another.

1. What Makes a Mineral
2. Identifying Minerals
3. Igneous Rocks
4. Sedimentary Rocks
5. Metamorphic Rocks
6. The Rock Cycle

How rock breaks down, how soil forms, and how water, wind, ice and gravity carve and build landscapes over time.

1. Mechanical and Chemical Weathering
2. What Speeds Up Weathering
3. How Soil Forms
4. Erosion and Deposition
5. Landforms Made by Water, Wind and Ice
6. Slow and Fast Changes

Fossils, the rules for putting rock layers in order, radioactive clocks, and the geologic time scale.

1. Fossils
2. Superposition: Reading Layers in Order
3. Cross-Cutting Relationships
4. Half-Life and Absolute Age
5. The Geologic Time Scale

The evidence that continents move, the kinds of plate boundaries and what forms at each, and how fast plates go.

1. The Evidence for Moving Continents
2. Seafloor Spreading
3. Three Kinds of Plate Boundaries
4. What Forms at Each Boundary
5. How Fast Plates Move

Seismic waves and how earthquakes are measured, kinds of volcanoes, hot spots, and forecasting natural hazards.

1. Earthquakes and Seismic Waves
2. Earthquake Magnitude
3. Kinds of Volcanoes
4. Hot Spots and Island Chains
5. Forecasting Natural Hazards

Where Earth's water is, how sunlight and gravity move it around, and the water hidden underground.

1. Where Earth's Water Is
2. The Water Cycle
3. Groundwater and Aquifers

What the atmosphere is made of, how pressure and uneven heating make wind, global wind belts, and air masses and fronts.

1. What Air Is Made Of
2. Layers of the Atmosphere
3. Air Pressure
4. Wind and Local Breezes
5. Global Winds and the Coriolis Effect
6. Air Masses and Fronts

How winds and density move the ocean, what sets a place's climate, and the greenhouse effect and today's warming.

1. Surface Ocean Currents
2. Deep Ocean Currents
3. Weather and Climate
4. What Sets a Place's Climate
5. The Greenhouse Effect
6. Evidence of a Warming World

Where Earth's resources come from, and how the number of people and how much each uses add up to an impact.

1. Renewable and Nonrenewable Resources
2. People and Earth's Systems